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Your daily forecasts from Boards.ie weather forum (NO CHAT)

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  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Wednesday, 13 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 13 to 19 Jan will all be fairly close to normal values.


    FORECASTS

    TODAY will see the last of the heavy rainfall in parts of north-central Ireland moving further east and into the Irish Sea. Some outbreaks of lighter rain may continue but there will be longer dry intervals, partly cloudy to overcast skies, some mist and fog especially on northern hills, and it will be quite mild, with highs 11 to 13 C.

    TONIGHT an area of light rain will move in from the Atlantic and winds will gradually turn more westerly and then northwesterly, with slowly falling temperatures. About 5-10 mm rainfalls are expected with this, heaviest across central counties and later into the inland southeast. Lows about 6 C by morning.

    THURSDAY the last of this secondary rainfall area will move off the southeast coast and the rest of the day should be essentially dry and a little cooler with highs 6 to 8 C in moderate northwest winds 30-50 km/hr.

    FRIDAY morning will be clear and frosty especially in the eastern half of the country, lows -2 to +3 C, then clouds will slowly increase ahead of an area of rain expected to hit the west coast around late afternoon. Highs will reach about 5-7 C in most areas, 7-10 C on the west coast. The evening and overnight hours will become blustery with heavy rain at times, and winds southwest 50 to 80 km/hr. Temperatures will tend to rise in most areas rather than the usual fall expected at night, and may reach 10 C at around 0300h Saturday.

    SATURDAY the cold front of this system will race through in the morning, clearing skies and turning winds westerly at about 50 to 80 km/hr, with possibly higher gusts especially near west-facing coasts. Isolated showers may develop in this windy regime and temperatures will be slowly falling through the day from morning values near 8 C to late afternoon readings closer to 4 C.

    SUNDAY will be partly cloudy and breezy, rather cold, with passing wintry showers on higher ground. Lows near 2 C and highs near 7 C.

    MONDAY one last mild sector in this series will race through probably during the first half of the day, with outbreaks of heavy showery rain and winds southwest to west 80 to 110 km/hr, then it will turn considerably colder and there may be some outbreaks of sleet or snow in strong northwest winds. Temperatures near 7 C at first, later close to freezing.

    The OUTLOOK has become quite uncertain but most guidance does agree on a cold, rather dry pattern setting in for a few days. Almost anything could happen later next week as guidance splits into many different camps, some show wintry storms developing with this cold hanging on or trying to deepen slightly, others show a fast return to mild weather and rain. We'll have to wait a few days to get any real clarity on which scenario is going to win out, but expect mid-week temperatures to be on the cold side around 5 C daytime and -2 C at night.

    My local weather saw the snowfall continue to mid-day, then change over to light sleety rain at times, and it has become quite foggy as temperatures are trying to push up above 2 C. The total snowfall over two days amounted to around 20 cms. When we have nicer weather later this week I'll try to get some photos of the rather impressive snow banks all around the town, haven't been up into the higher elevations yet this winter but I'm guessing from the talk I hear that there's over a metre of snow in the bush a few hundred metres higher up than the town which has about 60 cms level snow now (where not plowed, they tend to plow the streets, sidewalks and spaces in between all in one operation and so you tend to lose track of how much snow there is until you find some undisturbed ground, but there's a good two feet in the old system).


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Thursday, 14 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 14 to 20 Jan 2021

    -- Temperatures will average 1 to 2 deg below normal values.
    -- Rainfall will average 50% to 75% of normal values.
    -- Sunshine will average near or slightly above normal.


    FORECASTS

    TODAY will be rather cloudy with some brighter intervals developing. Most if not all areas will have dry conditions or at worst, brief intervals of drizzle or light rain in parts of the southeast. Winds will gradually become northwesterly at about 40-60 km/hr. It will be cooler than yesterday but not particularly cold at 7 to 9 C.

    TONIGHT will be chilly as skies clear to allow for frost and some dense fog patches, especially in the inland lowland areas of the southeast and central regions. Lows -3 to +2 C.

    FRIDAY will start out with some sunshine through increasing high cloud. You may spot a solar halo around mid-day as clouds thicken, then by evening it will be raining on the west coast but remaining dry to about midnight further east. Rather cold most of the day and getting milder in the evening to midnight/0300h period, temperatures rising slowly to around 7 C in the afternoon and 10-12 C overnight. Not very windy but somewhat stronger winds developing in the evening and overnight (southwest 50-70 km/hr).

    SATURDAY the cold front of this system will sweep through around 0300-0600h and partial clearing will follow as the rain ends quickly (10-15 mm expected by Saturday morning). The partly cloudy, breezy and cooler conditions will continue in the afternoon with temperatures slowly falling from morning highs of 10-12 C to afternoon readings near 7 C.

    SUNDAY will be partly cloudy with some good sunny spells in places, and moderate temperatures, a slight frost to start in some inland areas, lows -2 to +3 C then afternoon highs near 7 C.

    MONDAY will be overcast with rain becoming heavy at times by end of the day, strong south to southwest winds developing, lows near 4 C and highs near 10 C.

    TUESDAY ... the outlook has changed somewhat as this Monday low is now moving east somewhat slower than earlier expected, and won't be past the Irish Sea until about mid-day Tuesday. Therefore Tuesday will start out still rather mild and wet, with cooler air arriving in two waves, one around mid-day dropping temperatures to about 6 C then a second cold front in the evening pushing readings down to freezing or -1 C. Showers and strong westerly winds of 70-100 km/hr will evolve into wintry showers and snow on hills with northwest winds 80-110 km/hr with strong wind chill values by Tuesday night.

    The OUTLOOK remains a bit uncertain although various models seem to be converging on a shared solution -- cold air will build in for several days, it may not be quite the coldest possible air mass but it will feel very cold in brisk winds, daytime temperatures 2-4 C and overnight lows -4 to -2 C, passing wintry showers in northwest winds sometimes backing to southwest as troughs rotate around the now-stalled low (from Mon-Tues) parked near the coast of Denmark with a trough to another weaker low near the Orkneys north of Scotland. The big question is, how long will this cold air remain in place before the Atlantic, showing signs of re-energizing around Friday 22nd, pushes back with mild air and rain? Some models say the cold air will hold it back for several more days and yield around the 27th for a time, but with the cold air not pushed very far north and looking like it could make another surge to the south by early February. Other guidance suggests the milder flow will win out around the weekend of the 23rd-24th but it could come in with bands of snow, sleet and rain in succession as the cold air will be reluctant to leave such wonderful surroundings.

    My local weather involved a damaging windstorm at dawn; a large tree crashed down across the neighbour's front porch (luckily that house is unoccupied and for sale), the tree being totally uprooted by strong gusts. A deep low pressure area moved past us to the north and raced through Alberta later on (Wed afternoon local time) and is now in North Dakota. This is the low that will show up on Atlantic weather charts over eastern Canada by Sunday, a low heading into the Atlantic by Saturday is already moving through the southeast U.S. bringing them some sleet and light rain. This second low will probably stay west of Greenland when it recurves to the north on Sunday but new lows will form from its extensive warm sector by then. It's those new lows which are complicating the outlook (at this point the genesis for them would be very subtle waves along a cold front in the central U.S.). I can understand why computer models struggle with all these developments when they have to start with two systems that are so far apart now (this low and the Scandinavian high pressure promoting cold air) but will interact somewhere in between a week from now. Anyway, getting back to my local weather, the rest of the day stayed rather windy and the early morning mild temperatures near 5 C quickly fell back below freezing, resulting in all the slush created freezing up, and it was dangerously icy around our town by evening, and around -7 C. The low created a blizzard across some parts of the prairies (well to the north of the international border) and strong but mild westerly winds closer to the border -- it wasn't a true chinook as the air mass was only downsloping briefly and the stronger winds were well out into the flat country rather than near the mountain passes. I'm estimating gusts to 120 km/hr at my location based on how trees were swaying and howling noises -- we tend to get very strong winds here when a westerly wind hits as there's a gap in the local mountain range that funnels them, a strong northwest wind regionally doesn't do the same thing here.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Thursday, 14 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 14 to 20 Jan 2021

    -- Temperatures will average 1 to 2 deg below normal values.
    -- Rainfall will average 50% to 75% of normal values.
    -- Sunshine will average near or slightly above normal.


    FORECASTS

    TODAY will be rather cloudy with some brighter intervals developing. Most if not all areas will have dry conditions or at worst, brief intervals of drizzle or light rain in parts of the southeast. Winds will gradually become northwesterly at about 40-60 km/hr. It will be cooler than yesterday but not particularly cold at 7 to 9 C.

    TONIGHT will be chilly as skies clear to allow for frost and some dense fog patches, especially in the inland lowland areas of the southeast and central regions. Lows -3 to +2 C.

    FRIDAY will start out with some sunshine through increasing high cloud. You may spot a solar halo around mid-day as clouds thicken, then by evening it will be raining on the west coast but remaining dry to about midnight further east. Rather cold most of the day and getting milder in the evening to midnight/0300h period, temperatures rising slowly to around 7 C in the afternoon and 10-12 C overnight. Not very windy but somewhat stronger winds developing in the evening and overnight (southwest 50-70 km/hr).

    SATURDAY the cold front of this system will sweep through around 0300-0600h and partial clearing will follow as the rain ends quickly (10-15 mm expected by Saturday morning). The partly cloudy, breezy and cooler conditions will continue in the afternoon with temperatures slowly falling from morning highs of 10-12 C to afternoon readings near 7 C.

    SUNDAY will be partly cloudy with some good sunny spells in places, and moderate temperatures, a slight frost to start in some inland areas, lows -2 to +3 C then afternoon highs near 7 C.

    MONDAY will be overcast with rain becoming heavy at times by end of the day, strong south to southwest winds developing, lows near 4 C and highs near 10 C.

    TUESDAY ... the outlook has changed somewhat as this Monday low is now moving east somewhat slower than earlier expected, and won't be past the Irish Sea until about mid-day Tuesday. Therefore Tuesday will start out still rather mild and wet, with cooler air arriving in two waves, one around mid-day dropping temperatures to about 6 C then a second cold front in the evening pushing readings down to freezing or -1 C. Showers and strong westerly winds of 70-100 km/hr will evolve into wintry showers and snow on hills with northwest winds 80-110 km/hr with strong wind chill values by Tuesday night.

    The OUTLOOK remains a bit uncertain although various models seem to be converging on a shared solution -- cold air will build in for several days, it may not be quite the coldest possible air mass but it will feel very cold in brisk winds, daytime temperatures 2-4 C and overnight lows -4 to -2 C, passing wintry showers in northwest winds sometimes backing to southwest as troughs rotate around the now-stalled low (from Mon-Tues) parked near the coast of Denmark with a trough to another weaker low near the Orkneys north of Scotland. The big question is, how long will this cold air remain in place before the Atlantic, showing signs of re-energizing around Friday 22nd, pushes back with mild air and rain? Some models say the cold air will hold it back for several more days and yield around the 27th for a time, but with the cold air not pushed very far north and looking like it could make another surge to the south by early February. Other guidance suggests the milder flow will win out around the weekend of the 23rd-24th but it could come in with bands of snow, sleet and rain in succession as the cold air will be reluctant to leave such wonderful surroundings.

    My local weather involved a damaging windstorm at dawn; a large tree crashed down across the neighbour's front porch (luckily that house is unoccupied and for sale), the tree being totally uprooted by strong gusts. A deep low pressure area moved past us to the north and raced through Alberta later on (Wed afternoon local time) and is now in North Dakota. This is the low that will show up on Atlantic weather charts over eastern Canada by Sunday, a low heading into the Atlantic by Saturday is already moving through the southeast U.S. bringing them some sleet and light rain. This second low will probably stay west of Greenland when it recurves to the north on Sunday but new lows will form from its extensive warm sector by then. It's those new lows which are complicating the outlook (at this point the genesis for them would be very subtle waves along a cold front in the central U.S.). I can understand why computer models struggle with all these developments when they have to start with two systems that are so far apart now (this low and the Scandinavian high pressure promoting cold air) but will interact somewhere in between a week from now. Anyway, getting back to my local weather, the rest of the day stayed rather windy and the early morning mild temperatures near 5 C quickly fell back below freezing, resulting in all the slush created freezing up, and it was dangerously icy around our town by evening, and around -7 C. The low created a blizzard across some parts of the prairies (well to the north of the international border) and strong but mild westerly winds closer to the border -- it wasn't a true chinook as the air mass was only downsloping briefly and the stronger winds were well out into the flat country rather than near the mountain passes. I'm estimating gusts to 120 km/hr at my location based on how trees were swaying and howling noises -- we tend to get very strong winds here when a westerly wind hits as there's a gap in the local mountain range that funnels them, a strong northwest wind regionally doesn't do the same thing here.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Friday, 15 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 15 to 21 Jan 2021

    -- Temperatures will average 1 to 2 deg below normal, a blend of near normal to mid-day Tuesday 19th, and very cold readings expected towards the middle of next week.
    -- Rainfall will average 75 to 100 per cent of normal values, most of it coming in two periods, Friday night, and Monday afternoon to Tuesday morning. Some wintry showers will follow.
    -- Sunshine will average 25 to 50 per cent above normal, as several days will have good amounts of sunshine and the average at this time of year is only 2 hours of sunshine a day.

    FORECASTS

    TODAY will see increasing cloud dimming any early sunshine, once any fog lifts. Some patchy freezing fog and frost in eastern counties will dissipate fairly quickly but the temperature increase will be slow after reaching 3-5 C and it may still be only around 6 C by evening in some areas, 9-10 C in the west where rain will arrive as winds freshen from the south to 40-60 km/hr.

    TONIGHT will be windy and wet, with a distinct frontal passage after midnight that might produce a squall line feature, with strong wind gusts and a rumble of thunder possibly. About 15-25 mm rain could fall overnight, winds will veer from south to west-southwest with the frontal passage, peaking at 50-80 km/hr but with potential for higher gusts to develop especially through central counties. This front will be moving into the west coast around midnight and through Dublin around 0300h. Temperatures will be steady near 10 C until the front passes then will fall a few degrees to near 6 C by morning.

    SATURDAY will continue rather windy but skies will become partly cloudy with bands of showers feeding in from the Atlantic, 3-5 mm rainfalls are likely from these in western regions, trace to 2 mm further east (after the main band of rain exits). Winds westerly 40 to 70 km/hr, highs near 8 C.

    SUNDAY will have some morning frosts, and sunny intervals with cloudy skies at times in the west and north, only isolated showers likely, and a temperature range from lows near -2 C to highs near 8 C.

    MONDAY will start out dry and cold in the north and east, while turning quickly milder and overcast in the south and west with light to moderate rain. This may start as sleet on hills in the north around early afternoon. Winds will pick up from the east to southeast, slowly turning more southerly. Lows near -2 C and highs near 8 C.

    MONDAY NIGHT and the first part of TUESDAY will be influenced by the warm sector of an Atlantic low pressure system, temperatures will peak at around 11 C and there will be 15-25 mm rainfalls with winds south to southwest about 50-80 km/hr.

    TUESDAY mid-day to evening will be a period of strong west to northwest winds 70-110 km/hr and rapidly falling temperatures, with bands of wintry showers developing especially for Connacht and Ulster. Temperatures will be around 2 C by evening and wind chills near -5 C.

    WEDNESDAY will be windy and cold with snow showers, some wintry mixtures from these near sea level, but accumulations of 1-3 cm on some northern hills. There will be more frequent sunny intervals in the east and south coast counties where wintry showers may be more isolated. Winds northwest 70-110 km/hr will add considerable chill to already low temperatures, with morning lows near -3 C and afternoon highs near +1 C, possibly a bit higher near some coasts.

    THURSDAY will continue windy and cold, although winds will slowly abate to the 40-70 km/hr range. There will be more areas of wintry showers and snow on hills, with morning lows near -5 C and afternoon highs zero to +2 C.

    FRIDAY could bring some outbreaks of snow, the guidance is beginning to come together recently in terms of an enhanced risk of at least light snowfalls developing in the cold air, which may be at its most chilly state by then, with lows near -5 C and highs -1 to +1 C, in variable winds depending on how weak features evolve and move around the region.

    The OUTLOOK beyond that into the weekend of 23rd-24th and the following week remains more uncertain, with guidance still split on how many more days of cold weather might follow, some suggestions would place the transition to milder, rainy conditions over that weekend (with snow at first a possibility), other guidance says the cold will dig in and not get pushed out until mid-week (a trend which could keep falling further on into the future since the reliability factor is getting low by then anyway).

    My local weather was sunny with increasing high cloud, and the maximum temperatures ranged from -1 C up at my elevation to +3 C in the nearby Columbia valley, so we went there to bask in those milder conditions and do the monthly shopping. The difference in snow depth between our hilly location (40 cm) and the valley (3-5 cm with some grassy areas partly thawed out) was quite noticeable, and I assume if I went up instead of down I might find snow depths up to 80 cm in the alpine areas around here (the tree line in this region is 1600m and some peaks get up to about 2300m, we're closer to 1050m at my location). That strong storm that blew through a couple of nights back now is currently spinning around in Iowa and heading for the Ohio valley. It is pumping up some slightly milder air into eastern states but not very much above their normal January readings of about 7-10 C. Light snow covers the regions to the east and northeast of the storm, which has lost quite a bit of its energy in the past day or two.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Saturday, 16 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 16 to 22 Jan 2021

    -- Temperatures will average 1 to 3 deg below normal. It will be near or slightly above normal to mid-day Tuesday, then considerably colder for most of the second half of this interval, reaching 4-5 deg below normal at times then.
    -- Rainfall will average near normal values, however, almost all of it (now that last night's event is done) will occur on Monday night and Tuesday morning. Wintry showers will follow but these will not give much moisture.
    -- Sunshine will average 25 to 50 per cent above normal as all days except Tuesday are likely to bring some sunny intervals. January so far has averaged about 50 per cent above normal over a grid of reporting locations.


    FORECASTS

    TODAY will be cloudy with sunny breaks, these more frequent in the east and south. Occasional showers will be fairly frequent in the northwest and less frequent elsewhere, amounts generally around 1 mm but locally 3-5 mm in the northwest. Moderate westerly winds 40-60 km/hr (higher gusts near Atlantic coasts) and highs 6 to 9 C.

    TONIGHT will be partly cloudy to clear and some frost will develop, lows -3 to +2 C.

    SUNDAY will be sunny with increasing cloudiness, highs near 7 C.

    MONDAY will see some brighter intervals at first in the east and southeast, rather cloudy in other regions. One weak front will be edging into Ulster from the Atlantic during the day, while a stronger warm front moves into the southwest by late in the day, bringing rain and moderate southeast winds there. Morning lows -2 to +3 C and afternoon to evening highs 9 to 11 C.

    TUESDAY will see intervals of moderate to heavy rainfall, moderate south to southwest winds, and temperatures steady near 10 C. Much colder air will arrive in the northwest by late afternoon and will push into all other regions between then and midnight. Winds rather moderate with this system, as it has a lot of small trough features and the strongest winds will blast around the western periphery offshore, Belmullet may catch those at times on Tuesday night. Temperatures will fall to around 2 C in many areas by late evening and to -3 C by Wednesday morning, as sleety showers turn to snow especially over hills.

    WEDNESDAY will be windy and cold; the offshore strong west to northwest winds will move onto land in the morning and spread through all regions by mid-day, reaching 70 to 110 km/hr. Bands of wintry showers will form over the Atlantic and move inland, turning increasingly to snow as they get further inland and especially so when crossing higher ground. Some hail showers may also be in the mix, but the east and south will have some sunny intervals. Morning lows near -2 C and afternoon highs 2 to 4 C but feeling more like -5 to -8 C in strong winds.

    THURSDAY will be similar except that the wind speeds will be down into a more moderate range of 50 to 80 km/hr, temperatures in a similar range (-2 to 3 C) and scattered bands of wintry showers with some snow accumulations possible on hills.

    FRIDAY will be less windy but will remain cold, with sunny intervals and isolated wintry showers. Lows near -5 C and highs 1 to 4 C.

    SATURDAY remains a day of some mystery as model guidance ranges from a brief return to milder conditions with rain, to mixed bands of rain, sleet and snow from south to north, and also some scenarios of a wider snowfall event with strong east winds. Stay tuned on this one, it could go either way (I can predict who already said it will rain).
    Temperatures will be determined by which outcome prevails, the all-rain scenario would see a quick rebound to the 8 to 10 C range, the mixed bands would run from that value in the south, to 1-2 C north, and the mostly snow and south coast sleet scenario would probably involve temperatures near or slightly above zero.

    By SUNDAY that disturbance, on whatever track it chooses to take, should be over Britain or northern France and colder weather would set in again briefly, with temperatures near 2 C and north to northeast winds. There could be some localized wintry showers with that.

    The OUTLOOK for the following week is somewhat uncertain but would most likely see a succession of lows crossing Ireland with mixed bands of precipitation ranging from rain in the south to snow in Ulster and north Leinster. This could shift a bit in either direction, but a lot of the guidance ends mid-week so there is only one model to consult for the second half of the week; that one was trending milder at that point. But the others looked like they might not necessarily follow that lead.

    My local weather on Friday was very pleasant for this time of year, sunny with light winds, and a bit of warmth at mid-day (highs 4 to 7 C across the region), but quite cold as soon as the sun set, with clear skies. This allowed me to check for any signs of fading Jupiter, I knew that Saturn must be lost in the solar glow by now as it will be behind the Sun by the first of February, Jupiter is heading there too by mid-February. The local hills blocked out my view of Jupiter even as early as sunset, but there was a pretty crescent new moon with the earthshine on the dark portion quite prominent (meaning I could see the entire globe of the moon despite only the bottom 10% being in sunlight). I noticed also that Mars is considerably dimmer than at its close opposition in the autumn, it now looks no brighter than Aldebaran, the red star in Taurus (which you can see to the upper right of Orion on these winter nights). Have a look this evening and see how the Moon is looking with a bit more illumination by then.


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  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Sunday, 17 January, 2021

    Forecasts for Ireland



    TRENDS continue similar, temperatures expected to be mild to late Tuesday then turning a lot colder; near average amounts of precipitation overall but most of that on Tuesday and Wednesday; sunshine making enough appearances to keep up the pace of this quite sunny January (will report on whether we see any record values of sunshine by end of month).

    FORECASTS

    TODAY will be partly cloudy this morning with the sun gradually disappearing behind high and then medium level clouds streaming in ahead of a complex Atlantic low, but any showery outbreaks of rain later today likely to be confined to Atlantic coastal counties and rather light there. Winds light and variable at first, becoming southeast to south 30 to 50 km/hr at least near west coast by afternoon. Highs 6 to 9 C.

    TONIGHT will bring partly cloudy skies, isolated showers, lows 2 to 5 C but some local frost possible in northeast.

    MONDAY will be mainly cloudy with a slowly increasing southeast to south wind of 40 to 60 km/hr to 50-80 km/hr later, rain spreading into parts of the southwest and northwest as two frontal boundaries form and begin to work their way east across Ireland by the overnight hours. Highs will reach about 9 C in the south and 6 C in the north.

    MONDAY NIGHT will be overcast with outbreaks of rain becoming a bit heavier by morning, 5 to 10 mm in this stage, winds moderate southeast to south 40 to 60 km/hr, lows 3 to 5 C north, 5 to 8 C south.

    TUESDAY will bring intervals of rain, gradually adding up to 15-30 mm falls, with some showery bursts and some foggy intervals also, as temperatures slowly creep up to about 11 C in the south and east, staying closer to 6 C in the north where winds will back around to the northeast, while staying south to southwest 30 to 50 km/hr across the south. By Tuesday night, intervals of heavier rain in the southeast, rain turning to sleet and snow over Ulster and this mixture slowly pushing south into the north midlands, as temperatures there fall to near 1 C.

    WEDNESDAY the south may remain mild for part of the day but the colder air with the sleety mix turning to wet snow will push gradually south into all of the midlands and even parts of west Munster. Some clearing may follow in Ulster where it will be cold all day. Temperatures will range from 8-10 C in Wexford, Wicklow and the inland southeast, east Cork, to near 5 C in a narrow frontal zone from about Limerick to Dublin, then 1 to 3 C further north. Winds are expected to be rather moderate from the north to northeast in the colder air mass.

    A deep low pressure system will form rapidly Wednesday night over the northern parts of Britain and this will end the mild spell for southeastern counties of Ireland, allowing the colder air to start moving faster around the developing storm. Over in Britain, some very heavy snowfalls may develop over higher parts of northern England and southern Scotland. Over eastern Ireland, some bands of mixed wintry showers or sleet with snow on hills appears likely as north to northwest winds increase to about 50-80 km/hr (they will be much stronger over the Irish Sea and north-central Britain).

    THURSDAY then will see bands of wintry mixed showers, snow on hills and rain/hail likely at sea level, sleet in transitional zones. These bands may be quite strong in places giving thundery showers of mixed varieties. It will be quite cold, around 3 or 4 C, but morning frosts will not be severe as lows will be -1 to +1 C. Winds northwest 50 to 80 km/hr and possibly higher in gusts in exposed locations. Wind chills of about -5 C will be perceived.

    FRIDAY will continue rather breezy and cold with scattered wintry showers and a bit of snow at times on hills, some bright sunny spells too, lows near -3 C and highs near +3 C.

    The weekend of 23rd-24th looks rather unsettled and the storm track could be right across central or southern counties of Ireland, dividing a rather mild south coast from colder central and northern counties, and producing bands of rain, sleet, and snow from south to north. Temperatures are likely to be in the 7 to 10 C range in the south, 3 to 6 C central and 1 to 3 C north. This split scenario may continue with more lows racing along in a rather active jet stream and crossing Ireland at various latitudes, so the frontal boundaries may oscillate north and south from day to day; the net result will be a rather unsettled week and there is probably some potential for another strong low to form around mid-week, details on that are out of realistic modelling range at this point.

    My local weather on Saturday was overcast with a rather thin layer of stratus cloud just above us and obscuring the tops of hills just 2-3 km away and 200-400 metres higher than our location. It was almost dead calm with that and temperatures were around -2 C.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Monday, 18 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 18 to 24 Jan 2021

    -- Temperatures will average 1.5 deg below normal, a blend of 3-4 deg above normal to early Wednesday and 4-5 deg below normal thereafter.
    -- Rainfalls will average near normal to 25% above normal, and most of that will fall on Tuesday and Wednesday (some will be sleet or snow).
    -- Sunshine will be near normal by end of the interval, despite mostly cloudy skies for the first three days.


    FORECASTS


    TODAY will be overcast with outbreaks of light rain starting in the southwest by afternoon, spreading somewhat further north and east. Another area of light rain may brush parts of the northwest coastal areas. Highs 7 to 9 C.

    TONIGHT will be mild with fog and occasional rain, 5 to 15 mm by morning. Lows 7 to 9 C except 3 to 5 C in parts of Ulster. Winds in most areas will become southeast to south 40 to 60 km/hr, backing to northeast in parts of Ulster.

    TUESDAY will see rainfalls of 10-20 mm additional, with winds remaining moderate southeast to south 50 to 70 km/hr for most, easterly 40 to 60 km/hr in Ulster. Foggy at times especially over higher terrain, highs 10 to 12 C. Bands of heavier rain likely in central counties towards south Ulster, totals may reach 50 mm there by Tuesday night with flood risks in poorly drained areas.


    WEDNESDAY the rain will continue but will begin to turn to sleet and wet snow, from early morning in parts of the north, mid-day in Leinster, with snow starting to accumulate just before ending late in the day. Winds becoming northerly 40 to 60 km/hr, temperatures near 8 C in the morning in the southeast, otherwise 2 to 4 C most other areas, and those readings will reach the southeast by afternoon. Around +1C by evening with slushy accumulations on lower ground in Leinster, 5-15 cm snowfalls on hills.

    THURSDAY will become windy and colder, with bands of wintry showers, snow the main component inland on hills, sleet at somewhat lower elevations and rain/hail/sleet mixtures near sea level. Some sunny intervals between the bands of showers, winds northwest 80 to 110 km/hr. Morning lows near -1 C and highs 1 to 3 C except 4 to 6 C near Atlantic coasts.

    At this time parts of northern England and eastern Scotland will have near-blizzard conditions as the low intensifies off the coast of eastern Scotland.

    FRIDAY will be sunny and cold with isolated wintry showers, not as windy, lows near -3 C and highs near 4 C.

    The outlook for next weekend is uncertain, cold air will try to hang on but could be quickly replaced in the south by milder air near 8 C and rain, leading to snow or sleet in parts of central and northern counties. There is also a slight risk of snow in the south on Saturday morning from a weak low expected to track south of Ireland into France.

    That sort of pattern may repeat from time to time in the following week, with quick temperature changes as waves of low pressure move through Ireland from west to east in a rather active jet stream.

    My local weather on Sunday was rather cold with a light snowfall in the early morning, followed by misty skies with glimpses of sun and temperatures steady around -4 C.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Tuesday, 19 January, 2021

    Forecasts for Ireland



    TRENDS for week of 19 to 25 Jan 2021

    -- temperatures will average 2 deg below normal despite today being about 4 deg above, so otherwise rest of the interval closer to 3 below normal.
    -- rainfalls will be near average considering that almost half of this event's rainfall may have already fallen especially by the time many read this.
    -- sunshine will be near or slightly above normal despite a cloudy first two days.


    FORECASTS

    TODAY will continue mild and foggy in some areas with light rain at times in southern counties, trending to moderate or even heavy rain in the central and northern counties, where a further 20-30 mm may fall, giving totals by late tonight of 50 mm locally (south Ulster and north midlands most likely to see spot flooding problems, just a slow rise of the water table in general leading to saturation of poorly drained areas). Highs around 10 to 12 C for most, with southerly breezes 40 to 60 km/hr, but closer to 5 C in Ulster where winds east to northeast.

    TONIGHT will continue foggy and mild in the south with a bit more rain at times, lows 8 to 10 C, while precipitation turns sleety over the north in slowly falling temperatures and a gradually increasing northerly breeze, temperatures there close to 2 C.

    WEDNESDAY the cold air will continue a slow southward push, replacing the milder air rather quickly when it arrives, despite a lack of strong winds; rain will turn to sleet and then wet snow especially in parts of coastal and nearby portions of inland Leinster, with potential for a slushy accumulation of 3 to 6 cms on lower terrain by evening, and 10 to 20 cms "proper snow" on hills. Temperatures will be steady 2 to 5 C in the colder air mass, and will fall from near 8 C in the morning to that range in the southeast. Winds northerly 30 to 50 km/hr except somewhat stronger near west coast at times.

    THURSDAY as the storm system (Cristoph) develops a much stronger circulation over Britain, Ireland will also feel the stronger winds, northwesterly 50 to 80 km/hr, with bands of sleety mixed wintry showers likely, and some snow accumulations on hills in all regions. Very cold especially due to the wind chill, morning lows near -1 C and afternoon highs 3 to 5 C, temperatures sometimes dropping during or after snow showers.

    FRIDAY will start out with some icy roads and frosts with morning lows of -3 C or lower in some places, and the winds will have eased to 40-60 km/hr, still west to northwest mainly, before becoming more variable later in the day as a weak disturbance may cross the south-central counties, with sleet or snow possible (likely not very much). Highs about 1 to 4 C.

    Both days of the weekend are looking fairly dry but cold with little change in temperatures, possibly dipping a bit lower in some areas at night. (so lows -5 to -2 C, highs 3 to 6 C). Scattered but isolated wintry showers possible both days.

    By MONDAY a milder air mass will be pushing into the country from the west, arriving about mid-afternoon on the west coast and by evening in the east. There could be sleet changing to rain in some parts of the north however. Highs will eventually reach about 10 C probably near midnight, then TUESDAY will see colder air returning although not as cold as this coming spell, with the rain perhaps ending as sleet or wet snow before clearing, afternoon temperatures 3 to 7 C.

    The rest of next week also looks unsettled and variable in temperatures as a parade of rather weak disturbances sets up near the central latitudes of the country, dividing the country at times into a mild south and cold north, with some mixed wintry falls possible along the track of any disturbances.

    February may see an interval of colder weather developing after this variable period ends.

    My local weather on Monday was sunny and quite cold, with highs only reaching about -7 C. That is not abnormally cold around here in the heart of winter, locals would consider -15 to -20 unusually cold.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Wednesday, 20 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 20-26 Jan 2021

    -- Temperatures will average 2 to 3 deg below normal, falling into that range later today, then staying 3 to 4 below normal until about Monday night or Tuesday, with the rest of Tuesday milder. The week following looks quite variable and close to 1 or 2 deg above normal (that is 27 Jan to 2 Feb) but may end with colder weather.
    -- Rainfalls or melted wintry precip will average about 50 to 75 per cent of normal, a little more today then rather dry to the weekend, some more mixed falls late Monday and rain on Tuesday. The week following that should be rather active for rain and possibly snow later into it.
    -- Sunshine will eventually reach normal or slightly higher totals once today's cloud is gone.


    FORECASTS

    TODAY ... Colder air continues to press slowly southward and any parts of the southeast still above 8 C (when you read this) will soon turn colder also. Temperatures in most other regions are already in the 2 to 5 C range and will not gain much if any later today as the depth of cold air slowly increases. Any light rain falling in the colder air will eventually turn sleety and then to wet snow before ending this evening. Some parts of central and south Leinster could see slushy accumulations at lower elevations, of 1 to 3 cm by late afternoon; 5 to 15 cms of snow is quite likely on higher terrain in the southeast. Other parts of the country will have either mostly dry weather with a slow clearing trend, or isolated outbreaks of sleet perhaps only in drizzle form. Winds will continue rather light northerly (briefly moderate southwest in Wexford this morning) as storm "Cristoph" begins to assemble its various moving parts in the Irish Sea by later afternoon or evening. This low will develop much more rapidly between Manchester and Newcastle on its way to the North Sea off Scotland.

    TONIGHT ... Partly cloudy west, overcast east, some further outbreaks of wet snow or sleet, quite cold, with moderate northerly winds picking up slowly but surely to reach 40 to 60 km/hr northwesterly by morning. Lows around -1 C except somewhat higher near north coast and some parts of the Atlantic coast.

    THURSDAY will be breezy to windy at times with bands of mixed wintry showers developing especially around Donegal Bay and west of Galway and Clare ... these will push well inland moving a little south of due east, and dropping a wide variety of sleet, hail, wet snow and cold rain, partly separated out by elevation (snow will be most likely above 200m elevation, rain most likely near sea level). Highs 2 to 5 C inland, east and south coasts, but near 7 C on the west coast. Winds west-northwest 50 to 80 km/hr. Much stronger winds and heavy high terrain snowfalls are expected from storm Cristoph over in southern and central Scotland and parts of northern England, northwest Wales. There could be as much as 30-40 cms snow in places. The Dublin and Wicklow hills could see 5-15 cm additional, mountains in Ulster and Connacht could also see significant falls. Mountains further south will be more dependent on whether or not the sea effect bands happen to hit their vicinity or not. They could also get 5-10 cm falls if so.

    FRIDAY will be a more sunny than cloudy day, still quite cold, but not as windy. There will be a few weaker bands of sea effect mixed wintry showers, turning readily to snow inland Ulster and Connacht, but making little further progress breaking up around the midlands. West Munster could also still see a few isolated wintry showers. Morning lows near -4 C and afternoon highs 2 to 5 C.

    SATURDAY will be partly cloudy and there could be an interval of light snow in some areas, with coastal sleet, but this will come and go within a few hours, and other parts of the day will be brighter. Lows near -4 C and highs 2 to 5 C.

    SUNDAY will also be partly cloudy and cold with more chances for light outbreaks of snow or sleet, lows near -5 C and highs 2 to 5 C.

    MONDAY will be clear in the northeast with a sharp frost then eventually overcast like all other regions starting out, and a cold sleety rain or wet snow may develop by late in the day, lows -5 to -2 C and highs 3 to 7 C.

    TUESDAY a frontal system may divide the country around Mayo to Meath, with areas north of that prone to mixed wintry sleet and wet snow, areas to the south a little milder with rain, highs 2 to 4 C north, 7 to 10 C south.

    By mid-week more active disturbances are likely, and there could be further battleground scenarios with fronts dividing Ireland into colder north and milder south, but the boundaries may fluctuate further south at times, bringing sleety or snowy intervals as far south as inland Munster and south Leinster. One final push north around Thursday 28th may lead to a significant storm that I feel may not be entirely "visible" to the forecast models at this range.

    The outlook beyond that is for a somewhat colder interval with some influence from high pressure in Scandinavia, southeast winds and mixed bands of precip likely. A very strong arctic high has pushed west to the north of Siberia for several days now and the models say it will drop southwest towards northern Russia but most of it will return to Siberia; however, a bubble of high pressure breaks away from it and tries to work closer to Sweden and Norway. This holds the key to any possible colder spells in February, and may interact with the stronger stages of the stratospheric events that are already underway. So we can't rule out a more severe wintry interval than any of the three relatively tame ones we will have seen by then.

    My local weather on Tuesday was mostly cloudy but from higher layers well above the local peaks, so it was fairly bright despite all the cloud, and cold with highs around -5 C. Given the recent menu of weather, this means a lot of ice rather than slush on our streets and sidewalks, and tons of grit spread out to make them passable. I'm going to add a recent picture showing how much snow has accumulated here (about 60 cms) but at the same time, this is fairly normal and we lose track of it in town because wide areas are totally cleared of this snow (had to crouch down to take this picture and leave out the view of the cleared street).


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Thursday, 21 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 21 to 27 Jan 2021 --

    -- Temperatures will average 2 to 3 deg below normal.
    -- Rainfall will be near normal with some precipitation wintry at times.
    -- Sunshine will also be near normal values.


    FORECASTS

    TODAY will be breezy to windy at times with passing showers of sleet, cold rain, or snow, the snow more likely on hills above 250 m elevations. Some sunny breaks will develop especially in eastern counties. Winds west to northwest 40 to 70 km/hr, may ease for a time this afternoon. Highs 3 to 7 C.

    TONIGHT will be partly cloudy with further bands of mixed wintry showers, snow line coming down to around 200m asl where these showers encounter hills. Quite cold with northwest winds 30 to 60 km/hr. Lows -2 to +2 C.

    FRIDAY will be partly cloudy and windy with passing wintry showers, more frequently now of snow or hail. Winds northwest 40 to 70 km/hr with some higher gusts in exposed Atlantic counties. Highs 2 to 6 C.

    SATURDAY will be partly cloudy with more generous sunny intervals, isolated wintry showers, some small accumulations of snow at times, continued very cold with lows -3 to +1 C and highs 1 to 5 C.

    SUNDAY will continue breezy and cold with passing snow showers, lows -4 to 0 C and highs 1 to 5 C.

    MONDAY will start out clear with sharp frosts in many areas away from somewhat milder west coast counties, lows around -6 to 0 C. Increasing cloud leading to sleet by evening, highs 0 to 5 C.

    TUESDAY will become somewhat milder especially south of a Galway to Dublin line, where highs of 7 to 10 C are likely with occasional rain. Further north, sleet or wet snow may continue before turning to rain with highs 4 to 7 C.

    WEDNESDAY will be breezy and milder with rain in all areas, strong southwest winds developing, lows 4 to 7 C and highs 8 to 11 C.

    The OUTLOOK is unsettled with further battleground scenarios possible (rain south, sleet/snow north), and it may turn colder in general around the weekend of 30-31 January. There are some indications of more significant cold spells for February than these several January episodes.

    My local weather was partly cloudy and mild (near 4 C) by afternoon after an overcast and cold start.


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  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Friday, 22 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 22 to 28 Jan 2021

    -- Temperatures will average 1 to 2 deg below normal, a blend of cold to around Monday (3-4 below average) and milder after Tuesday (2-3 above normal then).

    -- Rainfalls will average near normal values and there may be significant amounts of snow in the precipitation.

    -- Sunshine will average near normal values.


    FORECASTS

    TODAY will be partly cloudy with longer sunny intervals in the east than elsewhere, rather frequent mixed wintry showers feeding in from the west and northwest, changing readily to snow over higher parts of the north and west, but the snow line will also be falling to lower elevations by afternoon and evening. Winds west to northwest 40 to 70 km/hr, adding some chill to daytime highs near 4 C in most areas, 7 C near west coast.

    TONIGHT will see some clear intervals developing, as wintry showers become confined to Atlantic coastal counties. Lows -4 to -1 C.

    SATURDAY will start out clear and cold in many areas, then will become overcast with intervals of sleet or snow developing. These may become rather heavy across the midlands and parts of Munster and Leinster by evening and into the overnight hours, 5 to 15 cm snowfalls are possible although some lower elevations could see mixing and lose some of that total accumulation. Highs 2 to 5 C.

    SUNDAY there may be a second wave of mixed wintry precipitation after some breaks in the overcast around mid-day and it will remain quite cold, lows near -2 C and highs near 4 C.

    MONDAY will have some morning frosts and a slow increase in temperatures later in the day but as rain hits the west coast during the night it may turn to sleet or snow inland for a time until Tuesday morning, temperatures starting out below freezing (lows near -3 C) and rising to the 3-6 C range.

    TUESDAY will turn slightly milder as rain pushes in slowly, turning sleet or wet snow over to rain eventually in parts of the inland north. Lows near 2 C and highs near 7 C.

    The OUTLOOK for the rest of the week is milder with occasional rain and strong southwest winds; timing is a bit uncertain with a number of separate systems expected at roughly 24-36 hour intervals; the strongest of these now appears likely to be the "hidden low" I mentioned as models pick up the energy peak timed for about Thursday night into Friday.

    Mild conditions may turn back to cold and snowy before the end of the weekend of 30-31 Jan, and the first week of February is looking rather cold in general with high pressure developing to the northeast, and winds turning easterly as a result. None of this is entirely "carved in stone" this far ahead, so stay tuned. This winter is probably far from done.

    My local weather on Thursday was sunny and cold with highs (up at our elevation) near -4 C. Despite clear skies overhead we also had cap clouds over local hills, some of which were over low hills to our southeast that don't reach any higher elevations than right around here (a creek valley is in between), so that was an odd sight that I hadn't seen here in my brief residence.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Saturday, 23 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 23 to 29 Jan 2021

    -- Temperatures will average near normal, but starting with two quite cold days around 4-5 deg below normal and transitioning to several days 2-4 deg above normal after mid-week.
    -- Rainfalls will average near normal, precip to include some wintry mixtures and snow at first, then mostly rain after mid-week.
    -- Sunshine will average 75 per cent of normal values as the second half of this interval will become rather cloudy.


    FORECASTS

    TODAY will start out frosty with wintry sunshine for many areas, some isolated freezing fog and locally icy roads, caution advised especially on secondary routes, rather slow to warm even to freezing in some areas, eventually highs will reach 1 to 3 C. Some mixed wintry showers mostly staying close to north and later west coasts.

    TONIGHT expect intervals of snow, as rain or sleet will move inland from west coast around 9 p.m. and spread into midlands by midnight, Leinster and east Munster by 0300h. Potential exists for 3-6 cm accumulations and possibly a bit more than that on some higher terrain. Mixed falls are most likely within a few kms of the Atlantic coast and in some lower portions of west Munster. Overnight lows around -3 C in some areas ahead of the snow, where skies clear, temperatures during the snowfall likely to be close to -1 C.

    SUNDAY will see this first round of snowfall ending with partial clearing to follow, quite cold with the snow only partly melted away before another round of perhaps more mixed wintry precipitation arrives from the northwest by late afternoon. This may also give 2-4 cm snowfalls in some parts of central, eastern and inland southern counties, but the rain-snow line may make it further inland this time before sleet begins turning to snow. Highs only 0 to 4 C.

    MONDAY will provide a third opportunity for some mixed wintry falls as a warm front approaches to end the cold spell eventually, but it will take some time to work its way through Ireland, arriving late Monday and spreading into central counties by Tuesday morning. Monday will start out clear in some areas with lows -4 to -1 C, then with increasing cloud, sleet may begin in some western counties towards evening. Highs 2 to 5 C.

    TUESDAY the warming will slowly continue with bands of snow, sleet and rain developing and pushing further east and northeast, reaching Ulster by afternoon or evening, as temperatures gradually rise to the 7-10 C range in the south and 4-7 C in the north.

    WEDNESDAY to SATURDAY will bring a parade of lows at almost a daily pace, each one of them could bring intervals of strong southwest winds and moderate to heavy rain showers, the winds likely strongest near the south coast at times (south to southwest 70 to 110 km/hr), but sometimes veering westerly producing stronger gusts near the west coast. Temperatures will be generally well above freezing with lows 2-5 C and highs 8-12 C.

    By about SUNDAY 31st colder air will be returning, another low will try to follow the same track as the earlier ones but may run into this cold air leading to snow in some parts, sleet or a cold rain further south. This will be followed by quite cold northerly winds around the 1st of Feb (MONDAY) and after that, a battleground scenario may develop as colder air will try to remain in control despite the Atlantic not being entirely shut down. Later into February there are signs of a deeper cold developing with intervals of sub-freezing temperatures and locally heavy snow potential as the very cold air crosses the Irish Sea (for east Ulster, Leinster) or nearby portions of the North Atlantic into Connacht. The ultimate source region for cold air, central Siberia, has become extremely cold in the past week with readings near -60 C, -45 C spreading past the Urals into northeastern European Russia. It should be noted the -60 readings are not only at the traditional frost hollow cold spots in eastern Siberia but at other locations further west where -50 C is often the winter minimum.

    My local weather has been sunny and cold during Friday's daylight hours and is now clear and very cold at midnight local time -- high of -5 C followed by readings now around -15 C. A nearly full moon is passing over top of Orion and is just about overhead here now. We're approaching lunar declination maximum when the moon is sometimes as much as 5 deg higher in the sky than the mid-summer sun appears in late June. This is a cycle of 18.6 years due to peak in 2024. Get used to seeing winter full moons very high in the sky as a result. Summer full moons will likewise appear unusually low to the southern horizon.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Sunday, 24 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 24 to 30 Jan 2021

    -- Temperatures will average about 1-2 deg above normal, despite today and Monday being rather cold.
    -- Rainfall will gradually accumulate to near normal values.
    -- Sunshine will average 75% of normal.


    FORECASTS

    TODAY will continue cold with more outbreaks of snow, sleet and mixed wintry showers. Caution advised this morning for icy road conditions scattered throughout the country after overnight snow or mixed sleety precipitation. The most significant chance for further snow will come in Leinster this morning to around early afternoon, as an interval of north-northeast winds allows snow showers to develop near the coast and perhaps as far inland as the midlands at times. Some further accumulations of 2-4 cm are possible. This is not going to be a particularly well-organized event and results are likely to be "hit or miss" in nature. Elsewhere, more isolated snowfalls are likely but the trend in west Munster due to somewhat milder temperatures there will be more towards mixtures of rain, sleet and snow on hills. Highs today will range from about 1-3 C in the north and east, to 5-7 C in the southwest.

    TONIGHT will become partly cloudy to clear at times especially over the inland southern counties where lows could fall to about -5 C. Further north, more cloud is likely with mixed wintry showers, some snow accumulations on hills in Ulster. Lows here will be closer to -1 C.

    MONDAY will bring mostly cloudy skies and outbreaks of sleet or light rain, with slightly milder temperatures developing in most areas, highs 4 to 7 C.

    TUESDAY will produce bands of wet snow, sleet and rain, all moving slowly north as warm fronts gradually overspread all regions. Highs 4-7 C in the north and 7-10 C south.

    WEDNESDAY will be breezy to windy with intervals of rain and milder temperatures, highs near 11 C. Rain may become quite heavy at times by Wednesday night into early Thursday (20-40 mm rainfalls expected).

    THURSDAY and FRIDAY appear likely to continue unsettled with strong winds at times and further rainfalls, possibly mixing with sleet in the north as colder air pushes some distance south. Highs will range from near 5 C in the north to 10 C in the south.

    The OUTLOOK calls for the unsettled weather to continue with frontal boundaries quite likely to stall out in some northern or north-central counties, with much colder air not far away over eastern Britain during the last weekend of the month and into early February. Not too clear at this point whether the more likely outcome eventually is colder or continued "battleground" scenarios as the Atlantic does not show strong signals of yielding to the slow push of colder air from Scandinavia (which is dependent on a source region further east in Russia and ultimately Siberia).

    My local weather on Saturday was overcast with a few patches of clear sky at times despite a lot of raggedy low cloud drifting around, and it continued rather cold with highs about -5 C.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Monday, 25 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 25 to 31 Jan 2021 --

    -- Temperatures will average 1-2 deg above normal, but the first and possibly also the last two days of the interval will be quite cold, mildest around Wednesday.

    -- Rainfalls will average near normal, most of the rain will occur around mid-week.

    -- Sunshine will average 50 to 75 per cent of normal.


    FORECASTS

    TODAY will start out bitterly cold with local freezing fog, widespread ice and partly refrozen snow making for some very slippery conditions, caution advised. Some hazy or misty sunshine at times later, with a very slow warming trend but eventually most places will see temperatures in the 3 to 7 C range. A few sleety showers will move slowly into parts of west Ulster and Connacht.

    TONIGHT will be overcast with light rain at times, spreading in from the west, not making it to the east coast until after daybreak. Lows 2 to 6 C.

    TUESDAY will see intervals of rain, 10-15 mm likely, with widespread fog developing. Although milder for most, it may remain quite chilly in parts of Ulster. Highs generally 8-10 C but only 3-5 C in Ulster.

    WEDNESDAY will bring further intervals of rain, with temperatures steady near 10 C. About 10-20 mm rain can be expected. There is a slight chance of this mixing with sleet in parts of Ulster and north Leinster.

    THURSDAY will become windy especially near the south coast, with outbreaks of rain turning to sleet over some parts of the north. Lows near 4 C and highs 7-9 C.

    FRIDAY will begin to turn somewhat colder with occasional light rain or drizzle, winds becoming northerly and temperatures slowly falling towards 4 C by late in the day.

    SATURDAY is expected to be rather cold and there is some risk of sleet or wet snow developing, with low pressure passing to the south. Temperatures only around 2 to 5 C.

    SUNDAY may turn somewhat milder again with rain, highs near 8 C.

    The pattern signalled by most guidance after the end of January into early February is rather cold with the risk of mixed wintry precipitation, although very mild air may not be far away from the south and could push in at times, but the same could be said for cold air near the northern counties. Whether or not any active "battleground" lows or frontal systems develop is not clearly indicated at this time range, but it would not be too surprising given the close proximity of these different air masses.

    My local weather on Sunday was overcast and quite cold with a few snowflakes from time to time, no accumulation however, and temperatures near -12 C.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Tuesday, 26 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 26 Jan to 1 Feb 2021

    -- Temperatures will average 1 to 2 deg above normal, although closer to average in the north.
    -- Rainfalls will amount to 25% above normal values in some parts of the western and central counties, otherwise close to normal or a little below in some places.
    -- Sunshine will average only 50% of normal and even that may be optimistic.


    FORECASTS

    TODAY will slowly turn milder, but rather cool air near the surface will persist for part of the day in the east and north, so that readings may stall at about 4-6 C there, further south, more easily reaching 8-11 C. Occasional rain will be heavy in a few parts of east Munster and later into the midlands. Further north it could mix with wet snow or turn to sleet at times, especially this morning.

    TONIGHT will be foggy with light rain. The milder air will stop pushing north and so it will remain close to 4 C in parts of Ulster and north Leinster, while staying in the 6-8 C range further south.

    WEDNESDAY will see outbreaks of heavier rain across central counties, and moderate to strong winds at times near the south coast (southwest 50-80 km/hr). Less windy further north, and still some tendency for cooler air to hang on near the surface in Ulster, keeping temperatures around 5 to 7 C there; otherwise highs will reach 10-12 C.

    THURSDAY will turn slightly cooler with further outbreaks of rain, or sleet in the north, temperatures will settle back to around 7 C in the south and 3 C in Ulster.

    FRIDAY will become colder with mixtures of cloud and sunshine, in northeast winds of 40 to 60 km/hr. Any precipitation is likely to be mixed and wintry but only small amounts are currently indicated despite that wind direction, the air mass seems a bit too stable to produce much shower activity. Highs will be 3 to 7 C.

    SATURDAY could stay fairly cold and there's a slight risk of sleet or wet snow in a few spots, although once again, guidance is leaning towards a dry and stable air mass that will eventually begin to yield to milder air by the overnight hours. Highs once again 3 to 7 C.

    SUNDAY and MONDAY another mild spell looms with rain or drizzle, potential for about 10-20 mm rainfalls each day. Highs 8 to 11 C.

    By TUESDAY (2nd Feb) it may begin to turn colder in stages and some guidance is more aggressive with this colder trend, if that guidance is correct there may be some localized snowfalls as early as mid-week. However we are into one of those slow motion advances of colder Russian air masses into northern Europe that can confuse the models for days on end, so the basic theme is going to be waiting for clearer indications of a colder spell that seems quite likely to come some time in early to mid February.

    My local weather on Monday was overcast and rather mild compared to the previous few days, with highs just under the freezing mark, and a skiff of new snow (less than 1 cm) in the morning. Colder air seems likely to push back in here soon though, as we're just in the weak and almost collapsed milder sector of a very weak low that dropped in between pulses of arctic air. On the hemispheric charts, there is strong high pressure now close to the North Pole and it connects to several other highs in Greenland, north-central Canada, and central Siberia. This has the effect of keeping weather patterns stagnant, since this polar high anchors any other cold weather regimes that might otherwise be on the move.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Wednesday, 27 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 27 Jan to 2 Feb 2021

    -- Temperatures will average 1 to 2 deg above normal, rather cold at times around this weekend however.
    -- Rainfall will average near normal values but could exceed by 25% in the central counties.
    -- Sunshine will average only about half the normal amount.


    FORECASTS

    TODAY will be overcast and mild to start, then rain will move in from the southwest and it could become rather heavy at times this afternoon and evening. Moderate southerly winds will develop, and highs will reach 11 to 13 C.

    TONIGHT some heavy bursts of rain and isolated thunderstorms will continue with total amounts of 20-30 mm possible, some spot flooding in central counties. Lows 7 to 9 C. It may turn somewhat cooler with fog, rain and drizzle mixing with sleet over north Ulster.

    THURSDAY will be somewhat cooler, and rather unsettled, with intervals of showery rainfall, some dry spells in the mix also, and temperatures around 7-9 C. The far north may become chilly again with highs 3-5 C.

    FRIDAY some partial clearing may develop across northern and some central counties, with winds turning to the northeast. It will remain around 7-9 C in most areas with colder air only reaching Scotland and perhaps northeast counties of Ulster. Some light rain may develop at times across the south coast counties.

    SATURDAY will have a cool and dry interval between the system for Friday, and rain moving in some time later Saturday or early Sunday (timing a bit imprecise as guidance is not that unified on this phase). It will remain rather cool with highs 6 to 8 C.

    SUNDAY has some uncertainties as well, rain seems likely but it could turn to sleet or wet snow in higher elevations. Temperatures will be on a very slow downward trend reaching perhaps 3-5 C by late in the day.

    The period from MONDAY to WEDNESDAY of next week, which is 1st to 3rd of February, looks like it could bring some battleground scenarios between mild air to the south and west, and colder air trying to work in from Britain, so at this time range the best outlook is probably to say unsettled with temperature variations across the country and the risk of some wintry mixtures as well as rain from time to time.

    Longer term, this battle between mild Atlantic air and a large area of very cold arctic air likely to spread all through Scandinavia and across the northern Atlantic, will continue with mixed results suggested by most guidance, the problem being that timing varies from one source to another, although they all seem to agree that neither the cold nor the mild regimes will totally win out, so a bit of everything can be expected as we work our way further into February.

    My local weather continued rather cloudy with a bit more snow, possibly 2 cms this time, and low cloud celings at times creating mist and obscuring the summits of even the low hills close by, with temperatures steady in the range of -4 to -2 C. Winter does not tend to drag on here like it might in some parts of Canada so I'm hoping to see the first signs of spring in this region later next month and certainly in March. Some signs of a pattern change for eastern regions of North America which have had almost no wintry weather since a snowstorm in mid-December, looking like some snow and colder weather is on the way for end of the month into early February there.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Thursday, 28 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 28 Jan to 3 Feb 2021

    -- Temperatures will average near normal.
    -- Rainfall will average 75 to 100 per cent of normal.
    -- Sunshine will average 50 per cent of normal, possibly less in the south, a little better in Ulster.


    FORECASTS

    TODAY will start out mostly cloudy with any remnant drizzle in the north gradually ending, otherwise, dry to mid-day or early afternoon for many, then intervals of light rain, and gradually increasing southwest winds in the south coast counties (less windy further north). Highs 8-11 C except 4-7 C in the north.

    TONIGHT will see a few further outbreaks of light rain and the moderate southwest winds 50-80 km/hr will gradually ease near the south coast, lows 4-7 C.

    FRIDAY will have a few dry intervals, as winds turn more southeast to easterly, then rain will arrive again in the south, west and central counties, spreading to Leinster by late afternoon or early evening. This rain could start to change over to sleet or wet snow on high ground because somewhat colder air will be gradually feeding into the rainfall but closer to the south coast it will remain 8 or 9 C and 15-30 mm rain can be expected there. Temperatures further north may slowly fall off to around 5 C at lower elevations, 2-4 C on higher ground.

    SATURDAY some rain will continue mixed with sleet or wet snow on higher ground in some parts of the south; it will likely be dry but mostly cloudy with a few brighter intervals further north. Temperatures will vary from 7 C in the south to 2-5 C in the north.

    SUNDAY another weak system will try to push the colder air back to the north but it may take until Sunday night before there is much change in the frontal zones, so that a cold rain in the south may trend more towards sleet or wet snow in central counties and if it reaches far enough north, measurable snowfalls are possible in south Ulster. Temperatures will remain around 4 to 7 C for most, 2 to 5 C north, and 10-20 mm rain or liquid equivalent can be expected.

    MONDAY the milder air may have one last attempt to push north, and may succeed briefly but then the system will weaken and colder air will seep back into the north later in the day. Some rain at times with fog likely, highs near 7 to 9 C in the south, 3 to 6 C north.

    By TUESDAY a somewhat cooler easterly flow will develop, and this could have some mixed wintry showers although it looks fairly settled, with highs near 5 C.

    The pattern for the rest of next week looks rather cloudy with east winds and perhaps a few more minor skirmishes in the south between somewhat milder air and the gradually dominating colder air. This could lead to a few intervals of sleety rain or wet snow. However, the big weather story may be what happens towards the end of next week, as most guidance seems to be tracking similar outcomes with much colder air settling into northern Europe and then gradually extending its influence over most of Britain, with Ireland perhaps in line for a visit too by about Sunday 7th February, and if so this could be quite a cold interval with snowfall potential especially near the east coast. By no means is this certain to happen (based on usual model reliability, about a 60-70 per cent chance however).

    My local weather on Wednesday was overcast with snow, which was heavier in the first half of the day and amounted to nearly 20 cms of light powder, it shovelled more like 10 cms so must have been moisture deficient. Temperatures were about -3 C through the snowfall. The east coast of the U.S. is about to turn very cold with a small disturbance bringing 5-10 cm snowfalls to North Carolina and southern Virginia late tonight (local time) then a stronger storm is expected from the central plains states by Sunday night and this could bring 15-30 cm snowfalls to the larger cities from Washington DC to Boston during Monday and Tuesday. The first low bringing some snow tonight will explode into a very powerful storm over the Atlantic but it looks set to miss Newfoundland as it curves up towards southern Greenland. It will be a hazard for shipping with winds reaching 160 km/hr south of Nova Scotia on Friday.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Friday, 29 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 29 Jan to 4 Feb 2021

    -- Temperatures will be near normal values in the south but could fall to 1 or 2 below normal in the north.
    -- Rainfall or liquid equivalent of wintry precip will total near normal amounts.
    -- Sunshine will amount to 50-75 per cent of normal.


    FORECASTS

    TODAY will be rather windy across the south coast counties, westerly veering northwesterly 60-90 km/hr. These stronger winds will be felt as more moderate west to northwest breezes further north except in a few exposed coastal areas. A few showers from time to time but also variable cloud with a few brief glimpses of the sun. Highs will be near 10 C in the south and 5-8 C in the north. Winds will abate after mid-day and will begin to turn more to the northeast or east in some places.

    TONIGHT rain will move in from the west and could be heavy at times in the south, temperatures steady 5-7 C with fog developing and 10-20 mm rainfalls expected there. Later in the night some mixed wintry falls may begin especially on higher terrain in central counties. It should remain largely dry further north, lows near 2 C there.

    SATURDAY the rain will continue for a time in the south before pulling away towards France, and any mixed or sleet/snow falls in central counties will also end, leaving small accumulations on some hills. Rather cold with winds east to northeast 40-60 km/hr, highs 5 to 7 C.

    SUNDAY more weak disturbances will move along a frontal boundary set up through south-central counties, and this could lead to snow in some central and eastern counties, as well as into the north at times, at the moment it looks like 2-5 cm accumulations are possible, will be checking this against updated guidance. Rain will continue in the south especially in west Munster, where highs could stay above 5 C, otherwise temperatures may slump down into the cold 1-4 C range.

    MONDAY looks somewhat milder again as another low pushes in but brings along somewhat milder air, at least temporarily; this milder sector will contain rain and fog and will push temperatures back to around 7 or 8 C for a while at least, but once again cold air will be lurking and mixing back south late in the day or overnight into Tuesday morning when rain could turn to sleet or snow.

    The outlook for the rest of next week is generally a slow downward trend in temperatures with a very cold interval signalled by much of the guidance towards the weekend of 6-7 Feb and into the following few days. There are hints of a strong northeast flow developing with this and bitter cold, broadly similar to what happened at the end of Feb 2018, but it's too early to place very definite forecasts on that possibility yet, let's just say for now that a significant cold spell with snowfalls could be experienced at least in Leinster and east Ulster by that time frame. Chances are probably not that much greater than 50-50 at this point so it's more of a watch than an alert.

    Meanwhile, my own weather has no shortage of snow, another ten centimetres fell during the morning and then it began to clear slightly but more snow has developed this evening here. On a day trip we noted that the valley ten kms to our east has only 15 cm snow depths, that increases to 35 cm about halfway up the hill to our town and then it's in the 70-90 cm range around town with 100-150 cms in the alpine according to skiers who go that way. We don't get a lot of wind with these snowfalls so it settles on everything including trees in a fairly even manner. Temperatures have been just a bit below freezing all through this prolonged snowfall event. This is basically the energy for the impending east coast storm expected from Sunday night to Tuesday 2nd Feb, most of the moisture is now past us and into Montana and Wyoming where the low is taking shape. It will be in southern Missouri by Saturday and then will transfer to the east coast from a centre near southern Ohio and eastern Kentucky on Sunday. Model forecasts for this storm are rather scattered but they all show some areas getting major snowfalls, it seems likely to me that they will all do well from it (from D.C. to Boston) eventually. The earlier storm I mentioned yesterday has blown out into the Atlantic after dropping 5-10 cms around Virginia Beach and northern North Carolina overnight. That one is not heading directly for your part of the world, most of it will get wedged in between Greenland and Labrador when the next storm develops this coming weekend. Uncertainty about the future course of this second low is probably the main reason why various model solutions for the eastern Atlantic are scattered but even so they all seem to be gung-ho on much colder air entering the mix. The source for this is not so much Siberia as a large high currently just on the Russian side of the north pole and edging towards northern Scandinavia.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Saturday, 30 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 30 Jan to 5 Feb 2021

    -- Temperatures will average near normal in the south to 2 deg below normal in the north.
    -- Rainfall will average 50% above normal in the south, trending to near or slightly below normal in the north. Larger portions of the precipitation will be in wintry precip forms further north too.
    -- Sunshine will average 25 to 50 per cent of normal.


    FORECASTS

    TODAY will be a raw, windy and wet day in most central counties, and somewhat milder but foggy or drizzly near the south coast. Some of the rain in Leinster could begin to mix with wet snow towards the end of the event mid-day, as colder air mixes in from Britain. Temperatures currently near 5 C in central counties will drop slowly to the 2-4 C range later, and readings 8-10 C near the south coast will fall off slightly also. Ulster and some parts of adjacent regions will escape most of this wintry mixed fall today and could even see some partly cloudy intervals. Winds for all regions will be rather strong east to northeast 50 to 80 km/hr adding quite a chill, not a day you would want to be outside for very long in central counties. About 20-30 mm rainfalls will be total amounts including what has already fallen (in many places about half of that).

    TONIGHT will have some clear intervals and a frost in many areas, lows -3 to +1 C. Winds not as strong but still fairly moderate from northeast to east at 30-50 km/hr.

    SUNDAY will see a weaker disturbance trying to push along the same frontal boundary which by morning will have slumped a bit further south. This means that a mixture of snow, sleet and rain will begin to fall in Connacht and possibly Clare (inland) before spreading into the midlands by mid-day. Current guidance suggests it won't extend quite as far as Dublin before changing to a cold rain, but probably on higher terrain in Leinster the mix will continue, as temperatures are not likely to come up much from the morning lows. Highs for the day only 3-5 C and that could be during dry intervals, with the precipitation temperatures may be fairly close to 1 C. Not as windy as today but some moderate east winds at times.

    MONDAY to WEDNESDAY the guidance generally suggests that a slight Atlantic influence will continue despite the gradual massing of very cold air over northern latitudes of the Atlantic and most of Scandinavia. Even so, some of the rather frequent light rain expected in this first part of the week could easily change over to sleet or snow in parts of the north and on higher terrain, with temperatures generally in the range of 4 to 7 C for most places, and 2 to 5 in the north and on higher terrain. Each day will likely have some intervals of light rain, fog and drizzle, with winds generally rather light as disturbances weaken upon approach from the west. Some intervals of stronger winds could develop near the south coast as these lows die out over Ireland and later south-central Britain or northern France.

    From THURSDAY to SATURDAY the guidance generally suggests that Ireland will be on the margins of a large outbreak of colder air with east to northeast winds. Some guidance says that temperatures will fall to very cold values as far west as Ireland, while other guidance limits the spread of this arctic air to eastern England and leaves the frontal zone somewhere near Wales. The latter is of course more likely than not whenever this split is suggested, but the colder guidance is quite robust in appearance so I am calling this a 50-50 proposition, whether or not Ireland gets into the coldest part of this developing arctic northeasterly outbreak. If Ireland does get in, some significant snowfalls are quite likely in Leinster especially. If not, then temperatures will remain in the 4-7 C range like the first part of the week, with drizzly light rain at times.

    Around SUNDAY 7th to TUESDAY 9th there seems to be an even greater chance of the coldest air reaching Ireland and this would be the most likely time then for a wintry episode of subfreezing temperatures and snowfalls. But it is by no means "carved in stone" that it would actually become that cold.

    Longer term in February, there are signs of further battles between the Atlantic and polar origin arctic air masses with some maps wanting to connect up all known sources of cold air into one gigantic pool of very cold air that would make February quite extreme. I find the parallel to Feb 1895 interesting because at the same time guidance is showing severe cold outbreaks in eastern North America and this combination happened in both that year and 1855, as well as 1917 to a slightly lesser extent. (1917 is remembered in Ireland for a massive snowfall that happened at the end of March and into early April). So let's say this winter has "form" but that alone is no guarantee of an outcome, in more recent decades of course the tendency has been for promising cold to push to the doorstep and then back away (this happened a few times in Feb 2013 before a cold March interval developed, it also occurred in other winters around then).

    I like to give you the probabilities rather than just picking A or B and hoping to be right on a coin toss. So you may hear different things from other sources who have decided to go with one or another of these possible outcomes.

    My local weather turned a bit milder which softened up our recent heavy snowfall accumulations, without doing much melting of it, with temperatures that edged up to around 3 C. We are expecting another 15-30 cm snowfall tonight and Sunday which is going to make for some interesting photos by middle of next week. We found a place nearby with an undisturbed winter snow pack that measured 85 cms. Now that is not present all over the town, it varies from 50 to 100 cms and then a lot of organized snow clearance takes place leaving some areas almost devoid of snow. After this next dump of snow we could be close to or over one metre around here.

    The east coast of the U.S. will get a heavy snowfall from Sunday to Tuesday, model predictions are over a fairly wide range but they all have some places getting two feet of snow, the most likely snow jackpot seems to be eastern PA, northeast MD and most of NJ, but anywhere from about southern Virginia to Maine could see heavy amounts. This may prove prophetic or not, but the models showing the most snow are also showing the deepest cold over Ireland, so I'll keep an eye on how that coupling unfolds and whether it proves predictive or just a background noise factor of no consequence.

    Just for interest, the degree of cold at present time (as shown for Ireland in 7-10 days) ranges from most extreme on the Canadian model, to medium extreme values on the U.S. (GFS) model, to weak on the European model. However a day or two ago the European model was showing a more robust cold solution and might return to that, plenty of time for models to "chop and change." The feature that seems to be giving the models difficulty is a strong high pressure area near the north pole that is gradually extending towards the Russian side, but some guidance has it pushing towards western Russia and Scandinavia, other sources say central to eastern Siberia. This seems to be making a large difference in the output for Europe.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Sunday, 31 January, 2021

    Forecasts for Ireland



    TRENDS for the week of 31 Jan to 6 Feb 2021

    -- Temperatures will average near normal values in most areas, could trend a bit below in the north.
    -- Rainfall will be 25 to 50 per cent above normal, with some wintry mixtures mostly on higher ground.
    -- Sunshine will average 25 to 50 per cent of normal values.


    FORECASTS

    TODAY will bring a steady, cold rain sometimes changing to sleet, that may mix with wet snow at times on higher terrain mostly, in parts of Connacht, south Ulster and Leinster. Winds southeast 50 to 80 km/hr and temperatures steady 2 to 5 C in most areas, 6 to 9 C in Munster. Rainfall amounts 20-30 mm. Best chance for any snow would likely be well up above most settled areas, 300 metres to summit levels, but some wet snow could mix in with rain without accumulating (some slushy 1-3 cm coatings) at lower levels.

    TONIGHT will bring a more intermittent version of this sleety rain and some intervals of sticking snow are possible on hills in the north. Lows 1 to 3 C.

    MONDAY a slightly milder air mass will push in and temperatures will slowly rise to near 10 C, with further rainfalls of 20 to 30 mm. Parts of Ulster will stay a bit cooler (5-7 C). Winds will turn more to the south then southwest at about 40 to 70 km/hr with some higher gusts near Atlantic coasts.

    From TUESDAY to about FRIDAY or even SATURDAY the situation will be fairly static, with weakening Atlantic lows trying to hold back a rather extensive area of cold air that will be making gradual progress into eastern Britain from the Baltic regions. This will lead to several days of very gradually falling temperatures, perhaps by about only one degree per day, and periodic outbreaks of light rain or drizzle, sometimes changing over to sleet on higher ground. Highs will be close to 8 C mid-week and still around 6 C by end of the week, lows will only be a couple of degrees below those as it will remain overcast and sometimes quite foggy with low cloud ceilings. At other times there may be brief brighter intervals since the various low pressure areas are likely to break up then will reform usually just to the west of Connacht.

    From about SUNDAY 7th to TUESDAY 9th Feb there is a window of opportunity for much colder air to arrive from the east and if it does so, temperatures could fall to near freezing with risk of snow in Leinster and east Ulster, brighter but cold conditions further west. This is still about a 50-50 proposition with the same models showing roughly the same outcomes as last night when we looked at this potential. I would imagine that by around Tuesday we will have a better idea which way this is going to go. I don't really have a strong hunch about it, but will be watching to see how things unfold in the next two or three days with the east coast U.S. storm which may influence the balance of power between the Atlantic mild and the north European cold regimes. The arrival of this colder air in eastern Britain is probably more certain, in the range of 70% likely, so there will certainly be some close calls if it doesn't make it all the way west to Ireland.

    Then the longer term guidance seems to suggest that if the cold does win out, it could persist for a while with only brief but possibly stormy interruptions. I think the other side of this coin would be a return to quite mild weather (that is if the cold only manages a brief or glancing appearance).

    Interesting anyway, but to get there we must endure a rather drab period this coming week, as the colder air does not seem to be quite aggressive enough to just blast through the dying remnants of this mild regime, although we should keep in mind that there might be a trend towards that more aggressive push south and west of the colder air towards late in the week (in other words, it could turn cold as early as Thursday, although confidence in that is low).

    My local weather on Saturday here was overcast with light sleety mixed rain and snow, turning more to a mist with snow grains at the present time, temperatures steady just around +1 C. The east coast of the U.S. will be getting blasted with heavy snowfalls and strong winds soon, the storm is taking shape to the west of the Appalachian Mountains already, with some outbreaks of heavy snow in northern Ohio and Indiana, and a cool drizzly rain in the weak warm sector further south. This low is about to give way to a stronger coastal low that has yet to make its appearance but will develop Sunday near Cape Hatteras NC. The storm is expected to last as long as two days in some of these states (PA and NJ are currently indicated as the heaviest snowfall targets, along with the NYC area and parts of northeast MD, so from Baltimore to about Boston MA eventually could see over a foot of snow.


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  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Monday, 1 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 1 to 7 Feb 2021

    -- Temperatures will average 1 to 2 deg below normal, starting somewhat above normal today and Tuesday, then gradually falling into the 3 to 5 below normal range by next weekend.
    -- Rainfalls will average about 75% of normal, most of which will come between today and Thursday; a drier interval will follow.
    -- Sunshine will improve to near normal values with a rather cloudy start.


    FORECASTS

    TODAY will be overcast in the north with occasional light rain, turning a bit heavier by afternoon and evening. Partly cloudy and mild further south with outbreaks of light rain developing later. Highs 9 to 12 C.

    TONIGHT and TUESDAY will see an interval of moderate to heavy rainfalls, 20 to 40 mm, heaviest north-central counties. It will be quite mild with overnight lows near 8 C and afternoon highs near 10 or 11 C.

    By WEDNESDAY it will have become partly cloudy with some persistent fog in north central counties slowly lifting, isolated showers, and slightly cooler, lows near 4 C and highs near 9 C.

    THURSDAY and FRIDAY will also be partly cloudy with isolated showers, lows near 3 C each day and highs 7 to 9 C.

    By SATURDAY colder air is likely to arrive from the east. At first it will be a dry cold with considerable sunshine, perhaps some isolated wintry showers in east coast counties. Highs would be 2-4 C and overnight lows into the -4 C range with chances of -6 C or lower further west.

    By early next week this colder air will come under attack from the Atlantic and there will be an increasing risk of snow or sleet with rain pushing into the south if the Atlantic air wins this battle relatively fast, some guidance shows the cold well entrenched through all of next week so that the only precipitation that could occur would be wintry, and there would be higher chances of the northern counties remaining dry. So that is the new range of model uncertainty as cold seems to be on the ascendant in this projected battle through early to mid February.

    My local weather on Sunday was overcast with light sleet or snow at times, turning to a steady accumulating snowfall by evening, projecting 15 cms new snow here by morning. The east coast of the U.S. continues to brace for the full onslaught of a winter storm that had a relatively mild opening phase on Sunday with 5-10 cm accumulations of snow fairly widespread in a region that could see 20-40 cm amounts later today into Tuesday (and locally as much as 60 cm in eastern PA, northern NJ and near NYC).


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Tuesday, 2 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 2 to 8 Feb 2021 --

    -- Temperatures will average 1 to 2 deg below normal mainly due to falling temperatures by this weekend.
    -- Rainfalls will average 75 per cent of normal values.
    -- Sunshine will average near normal as the cloudy regime begins to trend more partly cloudy over time.


    FORECASTS

    TODAY will be cloudy with a few breaks in the overcast this morning, mainly in eastern counties. Some vigorous showers are advancing through Munster at present and will reach Leinster by mid-day. As they slow down, they will begin to merge into longer intervals of showery rain, and more outbreaks of rain will follow from the Atlantic into western counties later. About 15-25 mm rainfalls can be expected. Quite mild with highs 10 to 13 C.

    TONIGHT will turn misty or foggy as rain tapers off to drizzle, lows 5 to 7 C.

    WEDNESDAY will continue rather misty or foggy with a few intervals of light rain, possibly a bit of partial clearing later in the day, highs 8 to 10 C.

    THURSDAY will be partly cloudy with isolated showers, lows near 3 C and highs near 8 C.

    FRIDAY will be partly cloudy with isolated showers also, lows near 2 C and highs near 7 C.

    The outlook into the weekend and next week has been trending colder in general; yesterday evening there was almost total model consensus for a strong cold spell on easterly winds and considerable snow potential -- this has now diverged with several models continuing to show that outcome but one in particular flipping back to a continuation of the current regime or at least only a very slight cooling trend over the weekend followed by a return to milder air.

    I am assessing the probability of the cold outcome to be something like 2:1 in favour, so will describe what I think that outcome would mean for forecasts, with the caveat that this is not a certainty yet.

    The weekend would likely turn colder in stages with temperatures near 5 C on Saturday and 3 C on Sunday. Any showers or outbreaks of light rain would begin to turn sleety and eventually could mix with snow.

    Even colder air could then arrive by later Sunday and persist well into next week, with moderate to strong east winds at times adding more chill, and potential for temperatures to fall to freezing or below in the daytime hours, and quite cold at night (-5 to -10 C). With the east winds and passing disturbances to the south, the potential for snow especially in Leinster and parts of Ulster and coastal Munster would become quite high.

    As I say, this is the "leading option" of those available, but there is still some chance of this cold outcome being avoided by a continuation of this current regime or at least the form it would be taking later this week when the Atlantic lows are weaker than today's. Hopefully the model consensus seen last evening will return later today and then stick around until we get to that cold spell.

    My local weather on Monday was rather dreadful, light rain and quite mild temperatures near 5 C replaced the falling snow around mid-morning and there's quite a bit of slush around as a result, with the snowpack reduced slightly. This should revert back to snow and colder temperatures soon with a re-freeze of the current messy conditions. Meanwhile the east coast storm hit with full force; New York City had 25-40 cm snowfalls, and reports of 50-70 cm from northern New Jersey into parts of eastern PA. New England states are seeing quite a mixture of wintry precip types, with the tendency being heavy snow west to sleet east (around Boston). The storm was more moderate for Baltimore and Washington DC which had perhaps 10 cm snowfalls on average. It's a rather complex and slow-moving storm that won't be totally finished with that region until Wednesday, with more wintry weather predicted over the coming two weeks including some very cold spells.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Wednesday, 3 February, 2021

    Forecasts for Ireland



    Going to a blog format just for today, as the most interesting part of this forecast concerns possibilities for a significant cold spell (with snow potential) next week.

    A weak (and slowly further weakening) Atlantic low will linger near or over Ireland most of this week. You may have heard a forecast for "cyclonic winds" and that refers to the fact that with the low situated at about the latitude of north Connacht, some northern areas will have strong east winds (Malin Head is showing that at present with gusts to about 85 km/hr there). Some areas further south will have winds from various directions controlled by the low pressure, for example, the east coast can expect south to southwest winds, the west coast more like west to northwest especially later today and tomorrow when the low finally moves onto land. So the term cyclonic here refers to the circular counter-clockwise wind flow always found near low pressure areas in this hemisphere.

    Our current example will continue to push slowly east and then north for a time (Thursday into early Friday) before being pushed back to the south later Friday into Saturday.

    That's going to allow a very gradual cooling trend as the weak low becomes encircled by somewhat cooler air from the northeast, not the full arctic air mass that might arrive next week though. Temperatures each day this week will likely be about one degree cooler each day, except that in north Ulster they will rise as the easterly is temporarily cut off. So expect highs of about 8-10 C today, 7-9 C Thursday, 6-8 Friday and probably Saturday also, then perhaps as low as 4-6 C by Sunday when the influence of the low should be replaced by the first stages of the (potentially) developing cold easterly.

    In that interval, overnight lows will only be a few degrees lower than the highs due to a fair amount of cloud in the circulation, so would expect lows near 4 C tonight, and again dropping off very gradually to around 1-2 C by the weekend.

    Showers or more prolonged intervals of rain with this dying low will be mostly confined to areas north of a Galway to Dublin line but not always so, and amounts will be fairly moderate (10 mm at most today, then 5-10 mm amounts for a few places each day after that, most places considerably less).

    These showers will begin to become more wintry by Saturday and especially Sunday, as the flow turns around more to the northeast with the departure of the low towards southern Britain and then northeast France. At the same time, the fresher northeast breezes will likely mean a decrease in cloudiness for western counties which may get to see longer bright spells each day by the weekend.

    The big question is, what happens next week? The model guidance has come together somewhat on that important question, but there is still a range of outcomes. The range has narrowed down to this essentially -- there almost certainly will be an easterly flow for several days, it will be at least somewhat colder than average for this time of year, and could be very cold indeed. The coldest days where guidance brings in the very cold option appear to be around Monday to Wednesday with some tendency on guidance for the cold spell to end gradually later in the week.

    If it's the modified cold option that wins (currently strongest on the U.S. model) then there wouldn't be much snow potential and temperatures would level off around 3-4 C daytime and -3 C overnight. Even with that some isolated snow showers might develop near the east coast. If the considerably colder options prevail, and most other model guidance suggests that now, temperatures may drop as low as -2 to zero C daytimes, and -9 to -5 C for overnight lows. As in normally the case with these cold easterly spells, colder temperatures are found further west especially in Connacht, away from the brief warming influence of the Irish Sea, which, like the North Sea, gets a period of time to work on warming up the surface layers of these cold air masses. That process leads to the formation of unstable shower bands known as "streamers" which then infiltrate both eastern Britain and eastern Ireland in turn, dropping snow or perhaps mixed wintry showers if the cold isn't quite robust enough. In general, these bands will be all snowfall if the temperatures at about 1500 metres (above the height of all terrain in Britain or Ireland) fall below about -8 C, which usually guarantees surface readings around 2 or 3 C. When we have more marginal "uppers" then the tendency is for the streamers to produce a wider mix of showers. That could be the case at first here, on Sunday when the coldest air is starting to arrive.

    Another mechanism for snowfall in these cold spells is the passage of low pressure areas to the south, without totally removing the surface layers of cold air. In those cases, the 1500m temperatures can be a bit more moderate to permit snow (-5 or -6 can work), since there is less of a maritime influence to consider, the cold air already being in place over Ireland when the moisture from the passing low is thrown over top of it. We can see several opportunities for such snowfalls in this coming cold spell, most notably towards the middle to end of next week. However, models have a fairly poor track record of "nailing down" these details at this time interval (currently about 7-10 days), so all I can say here is that in addition to the more reliable "streamer" type snowfalls in Leinster and parts of Munster and Ulster, there would be less predictable but more widespread snowfalls from passing lows.

    Of course, any arrival of lows that close runs the risk of pushing too far north to sustain the snow very long before it then turns over to sleet and rain. That development is more supported by the milder GFS model that I mentioned, as being the outcome fairly quickly after the modified cold that it predicts has come and gone. However some guidance that allows robust cold also goes into this faster transition to milder Atlantic air masses by about Friday of next week.

    So there's the overview and you can assess your forecast probability from that, I could pick a specific set of options and say that is what will happen, and in fact that's always what forecasters are doing, navigating what they think is the path of least resistance through a wide variety of outcomes (normally the first 2-3 days are fairly certain nowadays thanks to improvements in the technology of the models, after that, it becomes increasingly an educated guessing game based in large part on what confidence we have in different models, either against each other or within the range of their own internal uncertainties.) The GFS model helpfully (or perhaps not) provides an ensemble of about thirty solutions that could happen based on changing a few details of how the model runs, and this time out there is a very wide range in those outcomes after day five, which simply says the model recognizes that other model solutions could very well be correct, or at the other extreme, there might be a very brief and very modified cold spell. As always, time will tell but the bottom line is, the more significant cold and snow potential looks to be around a 70% chance now (applied to at least Monday to Wednesday if not a longer interval like Sunday to ??? ).

    In the past, cold spells have locked in for weeks in February, but most of the examples are well back in the past. The first half of February 1991 was quite cold then it warmed up to a more normal level. In 1986 there was more sustained cold most of the month. Other notable past Februaries with long cold spells were (going back in time) in 1963, 1947, 1917, 1895 and 1855. Most of these years produced some significant snowstorms in eastern Ireland. So that's the pedigree of severe cold at this time of year, and in almost all these cases, there was simultaneously some robust cold outbreaks in eastern North America. That's interesting because this is being shown on a lot of guidance at the present time also.

    My local weather on Tuesday was cloudy and mild, thankfully the light rain stopped falling and we have had a day of relatively benign conditions to deal with the slush and standing water problems before an expected freeze later today, as temperatures will be falling off from current levels near +2 C to around -3 C. More sleet is expected here by Thursday. The severe cold that I mentioned is further east and spreading in from a massive arctic high currently west of the Canadian arctic islands in the Beaufort Sea. A considerable portion of this severe cold is going to slump down behind the weak low that has formed to our east from the recent mild incursion from the Pacific. When that weak low reaches the Great Lakes it will be invigorated but that will just pull down more and more of the severe cold air towards the northern two thirds of the U.S. (lower 48 states). A long interval of much below normal temperatures is expected; so far models have been flirting with storms that could develop along the outer edges of that cold over the Gulf Stream, but most of the action is well offshore and aimed for the western Atlantic, so it would stay cold and dry on land in most cases.

    Will return tomorrow with a more standard forecast format.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Thursday, 4 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 4 to 10 Feb 2021

    -- Temperatures will average about 4 to 5 deg below normal, starting off near average and sliding gradually down into the frigid zone of 6 to 8 deg below normal next week.

    -- Rainfalls or the liquid equivalent of melted snowfall will amount to perhaps half of the average amount, although the amount of snow will likely be a significant portion of that and obviously above any long term snowfall average.

    -- Sunshine will likely average near normal as there will be a few breaks in the overcast most days and possibly some longer spells of wintry sunshine especially over the western half of the country next week.


    FORECASTS

    Will update the discussion of range of possible outcomes starting with the Monday segment of this forecast section today.


    TODAY will see a mixture of cloud and some sunny breaks although mostly cloudy further north with some further outbreaks of light rain giving 5-10 mm locally in Ulster, north Leinster, and 2-5 mm in parts of Connacht and the midlands. Generally dry in the south with isolated showers mostly near higher terrain. Winds generally light to moderate southwesterly although somewhat stronger in the east and north at times. Highs 7 to 9 C.

    TONIGHT will be partly cloudy to overcast with outbreaks of light rain mostly confined to the north and some central counties, lows 3 to 5 C.

    FRIDAY will have mostly cloudy skies with a few brighter intervals, as rain tapers off across Ulster, but then circulates back around from the north into Connacht, feeding later into parts of the midlands and Clare then eventually further south into west Munster by overnight hours. This rainfall will amount to around 5-10 mm, with the east and south somewhat drier. Highs 6 to 8 C.

    SATURDAY will begin to feel the first effects of colder northeast winds with bands of showers, turning somewhat more wintry at least over higher terrain, as temperatures begin to slide down gradually towards 4 C later in the day, still holding around 7 C in parts of Munster however.

    SUNDAY will become colder again with mixed wintry showers in moderate northeast winds 40 to 60 km/hr, a growing risk of snowfall accumulating on hills in the east, and temperatures steady in the 3 to 5 C range. At about this point in time the travelling low will have reached northeast France and Belgium where it will stall out and produce a sleety cold rain and snow mixture for eastern England with some heavy falls of all forms possible there.

    MONDAY / NEXT WEEK ... For next week, the guidance has begun to cluster more around one unified solution although there is still somewhat of a range of outcomes following on from what we discussed here yesterday ... there will almost definitely be a wintry spell from Monday to late in the week and moderate to severe cold as easterly winds set in at around 40 to 70 km/hr. The more moderate guidance still shows some mixing potential across the south and reserves the colder temperatures for the northern half of the country. The guidance that was more aggressive yesterday has either remained similar or intensified towards more extreme solutions. From all that, these would be the ranges of forecast conditions on a daily basis next week ...

    MONDAY will likely be quite cold and windy with some organized snow streamers, possibly mixing with sleet showers near coasts or more likely near the south coast which will get into the action partially, with the strongest wintry shower activity off the Irish Sea into Leinster and east Ulster. These snow (or mixed wintry) showers will sometimes make fairly significant progress across the central counties into some parts of west Munster and Connacht but the tendency will be for more sunshine and dry intervals on the Atlantic coast. Temperatures will start out in the range of -3 to -1 C and rise only slightly to 1 to 3 C, although possibly holding closer to 5-7 C in southwest counties.

    TUESDAY and WEDNESDAY will continue similar although if some guidance is correct the cold will deepen by about one or two degrees each day with nights reaching the -6 to -4 C range and days staying about -2 to +1 C (except somewhat higher right near some exposed coasts). More wintry showers almost all of which will be snow are likely and the dynamics may produce localized thundersnow showers. Amounts could reach the 10-30 cm range if some aggressive guidance proves correct. In the more moderate scenario, the snow will be more confined to the northern counties with a tendency to mixtures falling further south (although still snow on hills in that outcome). Temperatures would not be quite as severe in that option.

    LATER NEXT WEEK becomes quite interesting too with various scenarios on the table for (a) possibly an extended easterly cold spell, (b) possibly a vigorous battleground scenario with cold hanging on at the surface leading to heavy snow outbreaks, or (c) still the option discussed yesterday of a more progressive withdrawal of the cold towards the north confining any remnant snows to Ulster and changing the precipitation over to rain across large parts of Ireland. At this point I have to say that the middle option (b) seems the most likely of the three as the cold air will be entrenched but with so much of the guidance wanting to re-energize the Atlantic flow to the south, it seems to favour the outcome of occasional snowfalls in that later portion of the cold spell.

    Longer term, all kinds of scenarios are on the table and these range from prolonged cold, renewed cold after a brief interruption, mixed spells of cold and mild, or even a bit of a reversal to quite mild and stormy Atlantic dominated weather. I would favour the mixed spells of these options if I had to bet on one, but they all have some valid chance of coming to reality.

    So the current "bottom line" is that a fairly severe wintry outbreak seems all but locked in now, with a north to south gradient of probability ranging from near certain in the north to perhaps a 2:1 chance in the south. That would make the odds fairly high for central counties. The duration of the cold spell is perhaps more in question than its arrival which we could say is going to be gradual in stages over the weekend then more like "full on" by Monday or so.

    My local weather on Wednesday turned out quite sunny for a change as somewhat colder air arrived, temperatures hovered in the range of -2 to +1 C before dropping off more sharply after sunset, now partly cloudy and -7 C.

    The eastern U.S. are digging or melting their way out of the recent snowfalls and the storm made its way into Quebec and New Brunswick in eastern Canada. Very mild air was drawn up into the far eastern provinces with highs near 15 C in some parts of Nova Scotia and Newfoundland. That won't last very long before much colder air arrives in the circulation around the dying storm. Much colder air is heading south now behind a rather weak disturbance that is approaching the Midwestern states and this very cold air will gradually get a firm grip on all regions of central and eastern North America, with the west turning quite mild under a ridge located near the west coast. Temperatures as low as -45 C over the central arctic islands will push south and it will still be near -35 C when this air mass reaches the northern plains states and northern Ontario, to -25 C a bit further south than that. As the winter has been fairly mild the Great Lakes have very little ice cover and warmer than usual water temperatures in the 3-6 C range which is going to allow snow squall activity to become heavy by the weekend as winds increase to about 70 km/hr as the frigid air arrives there. One of the best analogues to what's happening generally is 1895 which was an exceptionally cold February in both western Europe and eastern North America.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Friday, 5 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 5 to 11 Feb 2021

    -- Temperatures will average 4 to 5 deg below normal.
    -- Rainfall, or melted equivalent of snow/ice pellets etc, will amount to 25-50 per cent of normal although snowfall itself will be more than the average amount (which blends about 90% no snow with 10% cases with variable amounts).
    -- Sunshine will be near normal at least in some western counties, may be reduced to 50% of normal in the east.


    FORECASTS

    Note -- the guidance has come together somewhat for this forecast period so you can assume these forecasts still have a possible range, albeit a narrower range than in previous discussions.

    TODAY will bring variable cloud cover with best chances for some sunny breaks in parts of the inland south, midlands and later perhaps the east coast. A band of showers is moving north along parts of the east coast and may remain in that vicinity while gradually weakening, then as low pressure reverses its course and starts heading back south by afternoon, showers or outbreaks of light rain will follow behind it into Connacht, west Ulster and eventually some parts of west Munster. Areas between those zones could have a largely dry day with isolated showers possible. It will continue relatively mild for one last day with highs 6 to 8 C.

    TONIGHT will be partly cloudy with passing showers or outbreaks of light rain, in northerly winds backing later to northeast 30-50 km/hr. Lows near 3 C.

    SATURDAY will be partly to mostly cloudy with some bands of showers, turning wintry on higher ground, moving in from the Irish Sea, especially by afternoon. It will feel rather cold in northeast winds of 50 to 70 km/hr, as temperatures stall near 3 or 4 C in many areas, possibly reaching about 5 or 6 C closer to the east coast and along the south coast.

    SUNDAY will become windy and colder and a few bands of wintry showers likely, some brief sunny intervals, and temperatures steady in the range of 2 to 4 C, but with east to northeast winds 60 to 80 km/hr, it will feel more like about -3 C. At this same time, parts of southeast England could be seeing heavy snowfalls from the circulation around the low we've been tracking, which by then will be around the border of France and Belgium. Snow streamers will be hitting parts of eastern England, and the same process will be trying to start up over the Irish Sea although it may be rather weak by comparison as the deeper cold air won't arrive over Ireland until Monday.

    MONDAY and TUESDAY will be similar days, cold and windy with localized heavy snow streamers from the Irish Sea and also into parts of Cork and west Munster from the Atlantic. Winds will be easterly 50 to 80 km/hr adding quite a chill to temperatures that will range from overnight values of -5 to -2 C, to daytime readings of about -1 to +3 C. Some of the localized snow streamers could contain mixed wintry showers at times, and there is potential for thundersnow or ice pellets. Further west, some areas may get brief sunny breaks but cloud will be fairly widespread. Snowfall potential is probably around 5-10 cm each day but those would be localized maxima and more generally you might expect 2-5 cm coverings topped up by similar amounts. Because of the banded nature of this snowfall, some places will inevitably fall between the chairs so to speak and miss out. The extent of snow through central counties might be fairly robust as some guidance shows the streamers still intact upon reaching Galway. In these setups there are places in the southwest and northwest that often miss out on snow and also remain a bit more temperate.

    WEDNESDAY could just be a third day repeat of the above, but some guidance also shows the closer approach of Atlantic moisture and warm fronts, which means that some parts of the south could come under a snowfall advisory if these fronts move close enough. That process tends to cut off the streamers to some extent, so the chances of further snow in central and northern counties may depend on the opposite trend. Temperatures will likely stay in a similar range, -5 to +2 C.

    The breakdown of this cold spell seems fairly quick on most guidance, with Thursday into Friday the most likely time for temperatures to begin to recover back towards normal mid-February values. The sequence of events is likely to be snow to sleet to rain then a dry, milder interval. Some guidance wants to reverse the anomaly altogether and bring in very mild air with temperatures of 12-14 C by about Saturday 13th or Sunday 14th. That could also be delayed into the following week but still come to pass then.

    My local weather on Thursday was overcast with light snow that began in the afternoon, and is now falling rather steadily with about 4 cm on the ground. This stops the ongoing decline in our snow pack which had at one point been close to 80 cms, and was about 50 cms before this latest event started. Temperatures were a bit colder all day around -3 C. A very extensive arctic outbreak is surging southward into all parts of Canada and eventually most of the U.S. except the southwestern states, by the weekend. We will get into the outer edges of that by Sunday here and have quite a cold week also.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Saturday, 6 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 6 to 12 Feb 2021

    -- Temperatures will average 4 to 5 deg below normal, with a slight moderation likely near the end of the week.
    -- Precipitation estimates are rather uncertain as most of the liquid equivalent will be late in the period and details about the "breakdown" phase of the cold spell are quite uncertain; my estimate is that near average amounts of precipitation are likely overall.
    -- Sunshine will probably not reach average mid-February amounts in very many locations, some western counties may approach those (2.5-3.0 hours a day). The average further east may be quite low due to frequent cloud cover.


    FORECASTS

    TODAY will begin to feel considerably colder as the first outer edges of the impending arctic air mass push across the Irish Sea on moderate northeast winds 50 to 70 km/hr. Skies will be mostly cloudy with a few breaks most likely towards the west coast. Some bands of mixed wintry showers will form and hail could be one of the more frequent components, along with cold rain, ice pellets and snow on some hills. Highs today only 3 to 6 C. It may be somewhat more moderate in parts of west Munster which will be feeling the full effects somewhat later.

    TONIGHT will continue mostly cloudy with mixed wintry showers, cold with northeast winds 40 to 70 km/hr. Lows will be in the zero to 2 C range, feeling more like -3 C.

    SUNDAY will be windy and cold with scattered wintry showers, as the colder air will not be fully assembled over Ireland until late in the day, the mixture of showers will be considerable and will take various forms, but some snow could begin to fall especially on higher terrain and in Ulster. At this point, storm "Darcy" as it has been named by various met services will be dropping potentially large amounts of snow, sleet and mixed wintry precipitation over southeast England, on higher ground there could be as much as 30 cms. The precipitation to hit Ireland during the cold spell is probably not directly related to "Darcy" but I'm sure the general public will think of the entire event as related if not integrated with Darcy, so having made that comment I am going to avoid talking about Darcy after today since I only consider the southeast England outcome really the direct product of this storm. Many other factors are going to be involved in what happens from late Sunday to the end of next week.

    MONDAY will become very windy at times, especially near the south coast, as a disturbance begins to move into France from the Atlantic by afternoon or evening. The day may start out fairly dry although quite cloudy and very cold, with a gradual increase in the coverage of westward-moving snow streamers. This passing storm's strong wind gradient will mean that any snow or sleet streamers that hit the south coast (around Cork) will be wind-driven and potentially quite stormy in that region, as winds could reach 70-100 km/hr, especially towards the overnight hours into Tuesday morning. ... The east coast will be seeing winds of 50-80 km/hr and bands of wintry precipitation gradually increasing in their extent, probably more snow than any other forms, but sleet or hail are possible, along with ice pellets and thunder. These bands will be both sporadic and shifting around in their locations, the net effect for most places in Leinster and the midlands will be intervals of snow or sleet and some brighter spells, accumulations of 5-8 cms will be fairly widespread, and 10-15 cms possible (especially on higher ground). Parts of the north will likely have more continuous light to moderate snow in east winds of 40 to 70 km/hr. Temperatures in all regions will be in the range of -1 to +2 C and feeling like -5 C in the strong winds.

    TUESDAY will probably see a repeat of these conditions, or a continuation of them. The tendency will be for conditions to deteriorate gradually on Monday especially towards afternoon and evening so that if there is any respite overnight it could quickly become stormy again on Tuesday morning, with temperatures steady around -1 C (possibly near +1 or +2 near some exposed coasts). Further scattered accumulations of 5 to 15 cms of snow are quite possible in many areas including the south coast, most of Leinster and Ulster, parts of south Connacht and more hit or miss in Munster away from the south coast snowfall area near Cork. There are chances that some areas will get heavy snowfalls and severe disruption although this is not a certain outcome (at least I don't consider it to be as certain as in storm Emma's rampage in the southeast in 2018). Hopefully later forecasts will give you more precise details and timing on disruptive snow events. At this admittedly early point in the preparations, I would say the best guess is localized maxima around 20-30 cms, more widespread 5-15 cm, and some lower accumulations even within the snowfall zones, with localized zero snowfall outcomes in the west.

    WEDNESDAY could see some continuation of these harsh wintry conditions although it may begin to abate somewhat depending on the details of a gradual warming trend that could begin to show itself in the south by later Wednesday. There seems to be a fairly high risk of snow or sleet developing after mid-day Wednesday but before that starts, a more stable atmosphere and a shift to southeast winds could cut off a lot of the streamer activity for a time. Also temperatures could begin to edge back up into the mixed precipitation zone (2-5 C). Ulster is the most likely region to see significant warm frontal snows from late Wednesday into Thursday.

    By THURSDAY this developing warming trend will probably begin to get considerably more organized and fronts will be advancing slowly but surely north and east, turning snow or sleet over to rain in southern then central areas, as temperatures rise slowly in the range of 3 to 7 C. Winds southeasterly 40 to 70 km/hr as a rough estimate (the details may turn out more intense however).

    The warming trend seems fairly robust on most guidance although I noticed the Canadian model was changing its theme from warming to a stalling out of moderate cold southeasterly winds and the chance of reloading the severe cold into the following week. I think that option is probably fairly unlikely to verify unless we see other guidance starting to trend in that direction, for the time being, the most reliable models are showing quite a strong warming trend that pushes temperatures up above 10 C eventually around the weekend of 13th-14th.

    So the summary would be this -- a gradual entry into the coldest air of this winter season, with full entry into the cold achieved by Sunday night into Monday morning from east to west, then increasingly harsh conditions likely reaching their most intense around Tuesday, followed by a gradual withdrawal from the worst of the chill and snowfall but perhaps with intervals of warm frontal snow to round out the wintry interval around late Wednesday into early Thursday (this part less certain at this more distant point in time). And any snow on the ground by that point will likely just melt away fairly gradually on Friday into Saturday due to milder temperatures and a little rain, hoping that the breakdown does not also feature heavy rainfall because that could produce a new flooding risk. (this does not appear all that likely given the sort of mild, dry pattern that is signalled for the weekend of 13th-14th).

    As to the geographical extent of disruptive snow, I am pretty sure we're going to end up with a patchwork quilt sort of outcome of various snowfall amounts as streamers come and go but tend to favour certain locations over others, but it should be underscored that parts of Cork need to be on alert for their own somewhat separate event due to the occasionally good potential produced by these winds between east and southeast at various times, whether this amounts to widespread light snow or localized heavier snow, it will be rather unusual for that part of the country. Central Leinster is probably somewhat more used to snowfalls and certainly they are reasonably frequent in parts of Ulster. The northwest will be more like a hit or miss zone of either no snow or some snow, as there's a lot of terrain to cross and the Irish Sea is rather narrow at that latitude for production so that it might take streamers hugging the north coast as cold air pours out of Scotland to get snow into some parts of Donegal for example. Snow could fall almost anywhere in this spell but if you had to guess places that would escape it, look for local examples of subtropical vegetation, it tends to grow in places that avoid wintry weather a lot.

    That certainly does not include where I live -- we had another 5 cms this morning followed by sunshine and gusty northwest winds, but it was also rather mild despite all that at 2-4 C up here and 7-10 C in valleys around southern B.C.; colder air is still massing to our north and spilling down the east side of the Rockies a lot faster than it's getting into the valleys between mountain ranges, but it's coming eventually to drop our temperatures towards -10 C next week. The eastern U.S. are now bracing for another snowstorm of 15-25 cms expected to hit during Super Bowl Sunday (7th) so many won't even notice it, I suppose, as it comes and goes within about six hours in some cases. After that storm, colder in stages along the east coast, with more slight snowfall events expected every few days and temperatures about ten degrees below their normal values.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Sunday, 7 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 7 to 13 Feb 2021

    -- Temperatures will average about 3-4 deg below normal, a blend of 5-6 below to Thursday and near normal Friday and Saturday.
    -- Rainfall or melted snow equivalent precipitation will probably begin to approach half of normal or a bit more towards Thursday and Friday after a generally dry start although some localized heavy wintry showers are likely at first.
    -- Sunshine will probably be less than half of the normal amount. A few places in the west could do somewhat better however.


    FORECASTS

    TODAY ... Turning colder in stages, more rapidly in north and east, as a frontal trough develops moving west about as far as a Donegal to Waterford line by late afternoon. This will be the leading edge of arctic air moving west from Britain, but its full effects will not be felt until Monday. To the west of this dividing line, any showers are more likely to be rain or hail than to the east where snow, sleet or hail are more likely (although cold rain showers could still be in the mix near sea level). Temperatures will stall at around 3-4 C in the colder sector and perhaps drop slightly this afternoon, while in the milder west and south, highs near 6 C can be expected. Winds throughout will be east to northeast at about 40 to 70 km/hr, adding several degrees of chill factor.

    TONIGHT ... Continued windy and cold with passing wintry showers, a bit of snow accumulation is possible in parts of north Leinster and Ulster, and on hills elsewhere. Lows near -1 C. Winds east 40 to 70 km/hr.

    MONDAY ... Windy and cold with a few areas of moderately heavy sea effect streamers containing a mixture of snow, sleet, hail or ice pellets, and cold rain showers. These will be most likely in east Ulster, north and central Leinster, near the Wicklow mountains, and later in the day near the Cork coastline. However, isolated snow showers are possible further west too. Thunder is quite possible with any vigorous showers that form. Local snow accumulations later in the day of 2 to 8 cms are possible but this won't be a widespread covering in all areas, some places may have traces that come and go. Skies will be partly to mostly cloudy with a few brighter intervals. Winds east to northeast about 50 to 80 km/hr in exposed coastal areas, 40 to 60 km/hr elsewhere, although west of Waterford on the south coast, the wind direction may become east to southeast at times. Highs will be in the range of 1 to 4 C.

    TUESDAY ... Windy and cold with more outbreaks of showery snow, sleet, hail and (even less likely) cold rain near sea level. Some of these once again could produce thunder. Strong east-southeast winds at times especially near the south coast, early in the day, abating somewhat later on. Otherwise, winds generally east 40 to 70 km/hr. Morning lows near -2 C and afternoon highs 1 to 4 C. Once again, 2 to 8 cm snowfalls are possible in some places, most likely central Leinster and east Ulster.

    WEDNESDAY ... Partly cloudy and very cold with brisk east winds becoming southeast 50 to 80 km/hr. Any wintry showers in streamers could be heavy in the morning, then the focus will turn to slowly advancing snow and sleet along warm fronts from low pressure attacking the cold air from the southwest. Morning lows near -3 C and afternoon highs near 5 C south and west, 2 C north and east.

    THURSDAY ... This warm frontal passage is expected to be slow and could take all of Wednesday night and part of Thursday before milder air gains much of a foothold in the south and west, with winds turning gradually more to the south near the Atlantic coast, remaining southeast in Leinster and Ulster. There is potential in this phase for 10-20 cm snowfalls to develop in Leinster, inland Connacht, Ulster and some parts of Munster such as Tipperary and Waterford. That could turn over to sleet or even freezing rain before the rain expected further west replaces it by late Thursday. Temperatures could be expected to warm up slowly to around 5 C in the east and 3 C north, while warming more readily to 9 or 10 C in the west.

    (some guidance earlier in the last 24h was showing this warming stalling out and not reaching the north and east until Friday, that seems to be replaced now by this somewhat faster timetable but readers should be aware that the whole concept of this breakdown of the cold spell is subject to a lot of variations as we get into the cold spell and even the addition of snow to the scenario is not necessarily a "given" yet, these are the most likely outcomes based on a blend of latest guidance).

    That being the case, by FRIDAY the most likely scenario is for a milder south wind and light rain at times, possibly with the existence of some colder pockets remaining in north Leinster and east Ulster with sleet or snow still a slight risk, and temperatures steady near 9 or 10 C with a moderate to strong south wind of 50 to 80 km/hr.

    There is of course a slight chance that the cold spell will extend longer and these milder temperatures will be confined more to west Munster and coastal Connacht.

    The general consensus of guidance beyond Friday is that high pressure will get even stronger over Scandinavia and after this mild incursion around Friday, the influence of the cold high will filter back into Ireland from the southeast with a slow fall off in temperatures to about 7 C on the weekend of 13-14 Feb and perhaps 3-5 C by Monday 15th. From there on the colder spell might even get back to more severe temperatures with snow potential, or it might stabilize at the cool but not frigid levels expected by Monday 15th, with slight variations until the high breaks down later in the week. Some earlier guidance had been showing this as quite a severe second cold spell with more snow potential, and this may return in later model runs, so all I'm saying here is that at the moment, guidance is giving this more moderate outcome, I wouldn't describe it as more than a medium-confidence sort of outcome.

    So once again to give a brief summary, expect it to turn colder in stages, with scattered wintry showers, many of them snow, here and there giving a rather variable result in terms of snow cover during the cold spell which now looks like breaking down slowly from Wednesday afternoon south and west, to Thursday mid-day east and north, with a fairly high risk of a snowfall in the 10-20 cm range at that point (but no guarantees on that yet).

    My local weather on Saturday was overcast with another light snowfall during the morning hours, about 7 cms, and temperatures just below freezing. It turned colder late afternoon and we are slowly getting into a much colder air mass that is pushing down from the north, at present it has reached -6 C here but stratus cloud has not yet cleared.

    The east coast of the U.S. will be seeing 10-20 cm snowfalls from a low just getting organized now near South Carolina, that will move quickly northeast to the Gulf of Maine by tonight (local time). It has turned very cold in the Midwest, readings of -25 C are being reported in Iowa during the late overnight hours there.

    Will be watching all forms of guidance and this next few days there may be more frequent forecast updates than usual, especially towards that breakdown period later in the week.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Monday, 8 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 8 to 14 Feb 2021

    -- Temperatures will average 3 to 4 deg below normal, coldest around Tuesday-Wednesday, somewhat milder by Friday-Saturday, then settling back below average again around Sunday.
    -- Total precipitation is likely to be near normal but the bulk of it will come on Thursday into Friday, and in many places will likely be a scenario of snow changing to rain; that phase will be fairly heavy on a daily basis but averaged over a weekly time frame closer to average in terms of total amounts.
    -- Sunshine will be at a premium and any places that see much sunshine will do well to reach half of the average for mid-February.


    FORECASTS

    TODAY will be windy and cold with a few localized bands of sleety mixed precipitation likely from the Irish Sea into central and north Leinster, as well as south and east Ulster. There could also be localized sleet or snow outbreaks in the Cork region by afternoon or more likely evening. Otherwise a lot of places will have a dry day with any localized snowfalls being in the trace to 3 cm range in most cases. Some sunshine could be recorded near the west coast but it will remain generally overcast. Highs will be in the 2 to 4 C range with winds easterly 50 to 70 km/hr adding a few degrees of chill to that.

    TONIGHT will continue overcast, windy and cold with the coverage of east coast mixed wintry showers perhaps increasing slowly and turning more to snow in the mixtures. Some potential exists for thunder near the coast. Localized snowfall amounts of 2 to 5 cm possible. Lows -2 to zero C, winds easterly 50 to 70 km/hr. There may be outbreaks of sleet or snow near the south coast where winds might be sometimes a bit stronger (60 to 90 km/hr).

    TUESDAY will continue windy and very cold with localized snowfalls in streamers coming in from the Irish Sea and along the south coast at times. Local snowfalls of 2 to 8 cm are possible. Mostly dry and cold in many areas however, and winds easterly 40 to 60 km/hr except 60 to 80 km/hr near the south coast. Highs 2 to 4 C.

    WEDNESDAY will see little change in the pattern, however winds will turn a little more to the southeast which may change the distribution of any sea effect snow streamers, making the south coast a more productive source, and shifting the inland trajectory more towards south Ulster and the north midlands. Lows near -3 C and highs 1 to 4 C in east-southeast winds of 50 to 80 km/hr adding a considerable chill factor.

    THURSDAY ... Most guidance now supports an active "breakdown" snowfall risk as milder Atlantic air slowly pushes into the far western counties but encounters resistance from the entrenched cold air. Snow may develop quite widely across many regions with potential for 10-20 cm amounts. It would change rather slowly to sleet and then rain only in the west-central and southern inland counties during the day, as temperatures worked their way up to 8 C in Kerry and 3-5 C in counties from Galway, Clare, Limerick around to Waterford. Lower temperatures would remain in place (-1 to +3 C) further east and north. Winds southeast 40 to 60 km/hr would turn more southerly in milder air to the west.

    FRIDAY ... According to most current guidance (and confidence in all this remains moderate), the fronts would continue moving slowly through eastern counties as the milder air gained more of a foothold over western and then central counties. There could still be outbreaks of sleet and snow in parts of Leinster and Ulster, and a gradual change to rain or drizzle later in the day (although the concept of the cold never being totally eliminated from east Ulster or north Leinster remains an option). Temperatures would slowly moderate in areas starting out cold, and eventually most if not all areas would reach 8 C or thereabouts in south-southeast winds of 50 to 80 km/hr.

    OUTLOOK ... There are two general themes in most guidance concerning weather trends for the following weekend and the week of 15 to 19 Feb. The first theme is that colder air won't be pushed very far to the east of Ireland and might remain in place as close as eastern Britain and the North Sea. That will make the weekend weather in Ireland mostly cloudy with near average temperatures in the 6 to 8 C range, possibly around 10 C in west Munster and coastal Connacht. Then a second theme emerges of a push back to the west of cold air, once again attacked by the Atlantic by about Monday in a second "breakdown" scenario although more of a frontal wave for the west which might not have gotten back into cold air before this begins. So another round of snow or sleet is quite possible around Monday in parts of eastern, central and northern counties. Temperatures would likely come back down to the 2 to 4 C range and after this event, fronts would not push back east but would tend to stall out and weaken allowing colder air to linger at least over eastern and northern counties for a considerable time into the following week. In fact some guidance suggests that there would be periodic renewals of very cold weather after that lasting well into the latter stages of February.

    My local weather on Sunday was partly cloudy to overcast and rather cold with temperatures around -6 C. Snow has come and gone through parts of the eastern U.S. and much colder air is pushing gradually further south behind this gradually intensifying low which will go on to produce blizzard conditions in Nova Scotia and Newfoundland today.


  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Tuesday, 9 February, 2021

    Forecasts for Ireland



    TRENDS for the week of 9 to 15 Feb 2021 --

    -- Temperatures will average about 3 deg below normal, starting out colder than that and moderating to near normal by the weekend; however there is some uncertainty about whether the milder air will have the same impact on trends in the east and northeast which could average 4 to 5 deg below normal.

    -- Precipitation will be around the normal amount but an unusual percentage of it is likely to be snow rather than rain, that being especially true in the east and north.

    -- Sunshine may manage to reach near average in a few spots but in general the cloudy conditions will be frequent enough to hold down totals to near 50% of normal.


    FORECASTS

    TODAY will be windy and cold with further outbreaks of light snow or in a few cases mixed hail and snow grains, or sleet. These outbreaks are most likely near the east coast, and will extend furthest inland around Meath and Cavan, while also there could be outbreaks of mixed wintry precipitation in parts of west Munster. Winds will be easterly at about 50 to 70 km/hr adding a chill to daytime highs reaching only 1-2 C in the inland west and north, 2-3 C in most other places. Some localized snowfalls of 2 to 8 cms likely, more widespread amounts in the trace to 2 cm range.

    TONIGHT will see a push of colder air from Scotland into Ulster that may spill out into parts of Connacht and north Leinster, and lows in these regions will fall to -4 to -6 C. That will have less effect on counties further south and west but it will remain as cold as this current spell has been, with lows -3 to -1 C. Winds may fall off somewhat to northeast 20-40 km/hr in the colder sector further north, while remaining east 40 to 60 km/hr further south. This may concentrate snowfall along a slight thermal boundary extending inland from near Dublin or just north of there towards Offaly and Roscommon. Localized snowfalls of 5-10 cm may develop here, and in a few other places near the southeast coast. At the same time skies may clear partially in areas further west.

    WEDNESDAY will be a mainly dry and cold day with the lingering chance of localized snow streamers, possibly affecting the south coast more as winds turn more to the southeast, but also continuing for the east coast and parts of the midlands to south Ulster. There could be some wintry sunshine at times, especially in the north and west. After the cold start in the north, highs may remain below freezing in some areas (-3 to -1 C) while further south the range is likely to remain similar to today at 2-4 C. Winds will turn to the southeast at 30 to 50 km/hr adding some chill to these readings.

    THURSDAY will present the risk of a widespread and disruptive snowfall in the 10-20 cm range, starting from early morning in west Munster, and spreading gradually throughout most of the country by mid-day. There could eventually be patchy freezing rain in counties (Clare, Limerick, Cork, south Tipps, west Waterford) closer to a slow-moving warm front that will try to push into west Munster, and rain is only expected in a few parts of Kerry and perhaps southwest Cork. Snow will fall at least intermittently if not continuously from mid-day Thursday to early or even mid-day Friday in some parts of the east and north, depending on how resistant the cold air proves to be. For Thursday, temperatures are likely to remain in the range of -3 to +2 C in the snowfall areas, rising slowly to about zero C in areas further west experiencing sleet or freezing rain, and more rapidly to near 7 C in outer headlands of Kerry, possibly about 3 C in coastal Connacht. Winds will be rather strong from the southeast (40-60 km/hr at least) during the snowfall although an inversion may prevent them from totally mixing down from the very strong winds aloft; those might break through in some coastal areas. The milder sector will have south-southeast winds of about 70 to 100 km/hr and 15-25 mm rainfalls by midnight.

    FRIDAY will continue with this regime of snow or sleet in the east and north, mixed falls of sleet or freezing rain pushing further east and north gradually, and the milder sector with rain spreading into most of Munster and Connacht by late in the day. Temperatures will slowly rise from near 2 C to about 7 C in some central regions, and will remain 7-10 C further west, but could be held down for most of the day near the east coast and in east Ulster, to values in the 2-4 C range. Once again, some uncertainty is involved in the timing, the cold air could prove even more resistant than this forecast assumes, or it could prove less resistant (I took the middle course from the guidance available).

    The OUTLOOK is quite uncertain and therefore a low-confidence forecast is all we can derive from the rather jumbled signals we're getting, with model runs changing every time out. There could easily be further changes before we get to the weekend or next week, so this rundown is more like a list of possible outcomes than a forecast as such. The milder air may manage to break through to the extent of holding on to control of Ireland and southwest England, if not any further east than that, for a day or perhaps longer, so that Saturday is most likely to remain fairly mild, with a low overcast, rain or drizzle, and highs near 6 C east to 9 C west, strong south winds making it feel rather raw despite those higher temperatures. That could hold for several more days but there seems to be a fairly high chance of the colder air, lurking fairly close after being pushed out, returning slowly towards Ireland and setting up another encounter with the Atlantic by Monday, but whether that one involves cold air or just a renewed rainfall is a question at this point. The most likely outcome seems to be a continued string of alternations between (somewhat) mild air and colder interludes with winds varying from south to southeast during each phase. If the Atlantic does manage to break through it currently does not look capable of bringing temperatures much higher than the 6 to 8 C range.

    My local weather on Monday was mostly cloudy and cold with readings near -10 C, as we slowly get deeper into an advancing mass of very cold air, most of which is going to stay on the eastern side of the Rockies and head for the Midwestern U.S. where parts of this coming week could see record cold temperatures, as will regions of western Canada further north and east from here. A 1065 mb high is settling into the Northwest Territories, that's about as high as the barometric pressure gets over North America, and temperatures with that are close to -45 C. Weak to moderate storms are forming every day or two along the east coast and heading out to sea, some are so weak that they are making the job of the computer models difficult, as they could develop further or perhaps just get lost in the larger vortex that is sitting over the western Atlantic in this current blocking regime.


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  • Registered Users Posts: 14,279 ✭✭✭✭M.T. Cranium


    Wednesday, 10 February, 2021

    Forecasts for Ireland



    (Blog format today, trends are generally upward in temperature and precipitation and same old flat line for sunshine)

    Cold air has deepened its presence somewhat overnight especially in the northern counties, and it now stands ready to battle the Atlantic which will be returning to its familiar haunts with a number of forays planned over the next three or four days.

    Today, expect mostly cloudy skies but the odd sunny break possible especially away from the streamers which will be generally most frequent in these areas -- the southeast and near the south coast, central and northern Leinster occasionally into the midlands, and east Ulster as well as a persistent band near the north coast of Derry moving across Inishowen in north Donegal. All of these streamers can be described as mainly light but occasionally moderate in their intensity, and capable of dropping 2-5 cm snowfalls in their life cycles. Otherwise the day will be largely dry in quite a few places that don't see any streamer activity. Highs today will likely reach about 2 C again in most places, but could be held down a degree or two on higher terrain. Winds will start out easterly, but with a slow veering towards southeast late in the day, in the 40 to 70 km/hr range mainly. This will add about 3-5 deg of wind chill to actual temperatures.

    Tonight, winds will be southeast 40-70 km/hr except in west Munster where they may increase to 60-90 km/hr. Cold air will be holding strong in most areas overnight and there could be some local clearing although some streamer activity and resultant snowfall will also continue, with the south coast becoming somewhat more prolific as a source due to the wind shift. Parts of Leinster and Ulster could see localized 2-5 cm snowfalls also. Lows will probably drop a bit from previous nights due to some clear patches developing, -4 to -2 C seems probable.

    THURSDAY will start out cloudy and raw with southeast winds of 50-80 km/hr. Some locally heavy snow streamers could develop ahead of the main storm event but many areas will have a dry morning. Snow turning to sleet near coasts will move into west Munster; the snow will likely be heavy on higher ground in Kerry and Cork, but wet and sporadic on lower terrain. In that region, the sleet may turn to rain by afternoon and temperatures could rise rather steadily to around 7 C. Otherwise the cold air will be much more resistant (at first) and snow could break out around mid-day in many counties between the south coast and through the midlands into Connacht and south Ulster. Amounts by evening could be 5-10 cm and this could cause considerable travel disruption especially for inter-city road travel. This snow is only likely to change to sleet right along the south coast and a few kms inland at low elevations. Any hills in this zone could see 10-20 cm snow amounts. By late afternoon or evening heavy snow is possible in the southeast and up the east coast towards south Dublin. Amounts of 5-15 cm are possible, 10-25 cm on the higher ground in the southeast. Much of the guidance suggests that Dublin (city) will be in somewhat of a snow shadow situation due to downsloping from the nearby hills, and snow amounts there could increase more slowly than in other areas (this remains to be seen). Temperatures during the snow event will likely be in the range of -2 to +1 C. Winds will be southeast 40-70 km/hr although sometimes in periods of heavier snow, east 20-40 km/hr. Any onshore flows such as would be expected in central Wicklow and parts of Wexford or Carlow would have a potential to see enhanced amounts.

    By THURSDAY NIGHT this snowfall will probably be weakening in general and also its western flanks will be changing over to sleet then rain as somewhat milder air creeps slowly further east, reaching perhaps a Sligo to Waterford line by about midnight or so. The rain in most cases will be rather light at first, becoming heavier later in the night in west Munster. Winds will continue southeast 40-60 km/hr where it is snowing or sleeting (and this activity will also be weaker in many cases), and will become south 50-80 km/hr in the milder sector with the rain. Temperatures will remain about zero to +1 C in the snow/sleet areas of east and northeast, and will rise to 4-5 C with the milder air oozing in (over snow that is melting, so some fog is likely with that).

    By FRIDAY some areas of sleet and snow may still be present especially in North Leinster and Ulster, and the further push of mild air will come to a halt for a time, with temperatures 0-2 C in the northeast, and 5-8 C elsewhere. Rain may become heavy at times in the south especially near hills. Winds southerly 50-80 km/hr. Friday night could see a brief push back to the west of the colder air which will be taking advantage of a weaker portion of the incoming Atlantic frontal system at that time. This may turn the rain back to sleet or wet snow in some areas of Connacht and the midlands.

    Then on SATURDAY the milder air will slowly start to gain further control but in doing so renewed snowfall or sleet could develop over parts of north Leinster and rain will spread further north and east once more. Eventually most of the guidance now agrees that milder air will push all the cold air out of Ireland and some parts of western Britain before running into greater resistance around central to eastern England. So for Ireland on Saturday, would expect most areas to be overcast with periods of rain and strong southerly winds 60-100 km/hr, with 20-40 mm rainfalls near the south coast, considerably less most other places, and temperatures 7-9 C.

    SUNDAY and MONDAY will likely continue with the rain, wind and milder temperatures, and rainfalls could become heavy to excessive near the south coast. Where this rain falls over hills that develop a heavy snow cover, strong melt-driven runoff could lead to stream flooding in the southeast, south central and parts of the southwest as well as possibly Connemara. Temperatures will be near 8 C much of the time.

    Now it should be said there is still a slight chance that most of this guidance is wrong about the mild victory over the cold and that the cold might put up a longer or more effective fight, so that needs to be watched, but the chances seem fairly good that mild is going to win based on the current model consensus. There will be times later in the week when renewed Atlantic systems come in but with some cooling of the general south to southwest flow between systems, they may not be starting off as mild as the previous system ended, so temperatures could fall back to the range of 2-5 C then go back up at intervals to around 8-10 C. Just looking at the guidance in broad general terms I would say there is likely a chance of one more cold spell taking place late in the month or more likely into early March. So I don't think this will be winter's "last hurrah" before a spring pattern dominates.

    My local weather on Tuesday was sunny and briskly cold at -12 C, and by late evening it had fallen to near -20 C, the coldest night we have had this winter so far. We are on the outer edge of a vast frigid air mass covering almost all of Canada and the northern half of the central to eastern U.S., and readings as low as -45 to -50 can be found well to our north, while -30 is common across the prairies and -25 C in the U.S. midwest. A frontal boundary running from around Oklahoma to Virginia is creating weak disturbances that could bring snow along that path in the next few days, and it's a bit milder to the south (although not above regional normals, near 10 C in the southeastern states is near or a bit below their average at this time of year). The air mass reaching Ireland has its origins in Russia and came across the Baltic regions as well as Poland and Germany. In central Germany this morning some lows near -20 C are being reported, and -10 readings extend into parts of Belgium and the Netherlands. There are also some places in Scotland below -10 C at this hour although -5 C is a ballpark average there.

    Unless I want to make a substantial change to the snowfall outlook for Thursday-Friday, there won't be an update issued but that will be assessed around 4-6 p.m. from later guidance.


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