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Sunday, 21 December, 2014

Forecasts for Ireland

Two notes of interest from the astronomy file. The winter solstice takes place just before midnight at 11:03 p.m. and then it will be new moon a couple of hours later at 0136h Monday. There won't be a solar eclipse anywhere as the Moon passes about five degrees above the Sun (as seen from the Pacific regions where that time would be high noon).

As to the complex weather scenario after Christmas, the guidance is finally beginning to show a semblance of convergence on a solution, so today's forecast will represent a consensus of the various models. Confidence in any of this guidance remains moderate rather than high, things may change closer to the time. I think the outlook for the 24th and 25th is fairly reliable at this point, 26th a bit speculative and 27th and beyond just a very rough estimate, it could be considerably more wintry.

TODAY and MONDAY will see another very mild spell night and day with temperatures steady around 10 to 12 C in moderate southwest winds. There will be occasional rain but amounts won't be too heavy, 5-10 mm on average today and 10-15 mm on Monday heavier in the northwest than most other places. Gusts to about 70 km/hr or a bit stronger near the Atlantic coasts.

TUESDAY will continue rather mild but it will turn slightly cooler by afternoon and evening, morning lows near 5 C and afternoon highs 8-10 C except 9-12 near the south coast. A few showers will come and go. Moderate westerly winds gusting to 60 km/hr.

WEDNESDAY (Christmas Eve) will be partly cloudy and rather cold with light mixed wintry showers in a somewhat slack westerly wind flow, and some snow could fall on high ground, with morning lows near 1 or 2 C and mid-day highs near 5 C. By midnight it could be close to -1 C with a frost developing.

THURSDAY (Christmas Day) will be partly sunny aside from some morning ice fog and daytime isolated showers of hail or snow. Most places will likely stay dry. Morning lows near -3 C and afternoon highs 4-7 C. The most likely place for any snow would be hills around Donegal and Mayo, Sligo and Leitrim. There could be some sleet or light snow in a few places by late evening into the early hours of the 26th.

FRIDAY (St Stephen's Day) is more likely to turn a bit milder after a very cold start, and that could lead to some light sleet or rain. Here's where the guidance remains somewhat inconclusive, but I'll say for now expect some rise in temperature from morning lows around -3 to -5 C, to afternoon readings about 6-8 C.

OUTLOOK ... Becoming rather windy and turning colder in stages through the weekend of 27th-28th. Highs about 4-7 C on Saturday and 2-5 C Sunday, showers becoming more mixed and wintry with increasing risk of snow accumulations in the north and west especially inland above 100m. Winds are most likely to come from a west to northwest direction but could be quite variable for a time if low pressure forms very close to the west coast as some guidance suggests. There is some chance of heavy snow flurries and strong wind gusts by Sunday into Monday although perhaps an equal chance that it will be a mostly dry sort of cold spell that features isolated mixed showers. This colder spell could last for several days or even a week before any significant warming, so expect quite a few sharp frosts and daytime readings struggling to get much above freezing (3-5 C might be about it).

All of the above would generally apply to most of Britain but you could expect that any mild weather returning on the 26th (Boxing Day to them) might persist well into the 27th in the south, whereas conditions will be more similar to Ireland in most of Wales, northern England and Scotland, and in fact there might be more frequent and heavier snow there during the period 27th-29th.

North America continues to experience widespread bland, mild weather that will slowly break down over most central and eastern regions around Tuesday with a strong storm system due to move north into the Great Lakes, with strong southwest winds and a sharp temperature drop from near 15 C ahead of its fronts, to -5 C by Christmas Day (hence it is being dubbed the "Santa-bomb") -- lake effect snow squalls and east coast thunderstorms and damaging wind gusts are possible during Christmas morning (as if it isn't hard enough to get the kids to sleep). On the west coast, we're looking at occasional bursts of heavy rain to Monday then a colder trend that might end up with a little snow at least on hills by Christmas Eve. ... Saturday here was a wet day with highs near 9 C and about 25 mm of rain.

Tuesday, 23 December, 2014

Forecasts for Ireland


The forecast situation remains about the same as yesterday. Thus the forecast below will read about the same as yesterday and if you remember that one, I would skim through and then just go to the end and read the further outlook. There are some new thoughts there perhaps.

TODAY ... Still very mild but turning slightly cooler and fresher in two or three minor steps over the rest of the day. Temperatures will tend to stay about where they are now (10-11 C south, 8-9 C north) to mid-day then slide down about three or four degrees by evening. Winds will be westerly at about 50 to 70 km/hr and there will be a band of moderate rain that will continue south and east giving 5-15 mm rainfalls, followed by more scattered and sporadic showers once the cloud cover breaks somewhat.

TONIGHT ... Turning rather cold except perhaps near the south coast, lows will range from 2-4 C inland to 4-7 C south coast. Showers will ease and some places will have a largely dry night.

CHRISTMAS EVE (24th) ... A bright and bracing sort of day with towering cumulus cloud capable of unleashing brief showers of rain or hail, and maybe a touch of snow on higher summits. Moderate westerly winds 50-70 km/hr, highs about 5 or 6 C for most, 8 C south coast.

The overnight hours that people actually call Christmas Eve will be dry with clear patches developing, and those might eventually generate some shallow fog or freezing fog. Roads could become rather slippery by midnight and thereafter. Lows will reach about -2 C inland, +2 around most coasts.

CHRISTMAS DAY will start out with filtered sunshine through increasing higher cloud, except where any fog persists. There will probably be a thick hoar frost in shady spots that could last all day despite highs near 5 C. One or two mixed wintry showers will probably drift inland around Donegal and Mayo and a few lucky areas could get a dusting of fresh snow during the day, almost all areas further east and south will remain dry except for the hoar frost. The evening will remain cloudy in the west but clear patches will develop again in Leinster and east Ulster where it could become as cold as -4 C before warming up again.

ST STEPHEN's DAY (26th) will start cloudy and cold, winds will slowly pick up from the south, and a band of mixed sleety precipitation will spread in (mostly rain near sea level), all changing to moderate rain by evening and overnight into early morning of 27th. Lows -2 but rising then highs 6-8 C except possibly about 3-4 C inland north.

SATURDAY (27th) will be the day to watch, most guidance suggests a mild and windy start with temperatures near 7 or 8 C for a few hours, then strong westerly winds shifting rapidly into the north, falling temperatures to about 2 or 3 C and pelting showers of hail or sleet that will likely turn readily to snow over higher elevations than 150m above sea level. You might be quite likely to encounter snow if you drive any distance and especially if you venture into hilly areas. Winds will be at least 50-90 km/hr and could reach 110 km/hr in gusts over exposed locations, if the storm deepens close enough to Ireland, as 130 km/hr seems possible in eastern Scotland and northeast England.

SUNDAY (28th) seems likely to remain windy and very cold with passing showers of hail, sleet and snow. There is some chance it won't be quite cold enough for much mixing but also some possibility of near-blizzard conditions at times in the north and even for a brief interval in Leinster. Places such as Cork and Waterford might only see brief passing showers leaving little or no accumulation. Further north there could be 1-3 cms of snow here and there, and 3-5 cms in more exposed parts of Ulster and north Connacht. Winds might stay northwest to north all day or could possibly turn more to the northeast if low pressure dives south into France as shown on some guidance. That's when some interesting sea effect streamer action could be added to the mix around Dublin, but only if the winds make that turn. More likely streamers would be found coming off the North Atlantic around Donegal Bay. Expect morning lows of about -4 C or lower in some places, and afternoon highs of 2-4 C feeling more like -5 C.

MONDAY will likely remain quite cold but less stormy, with isolated mixed wintry showers, lows near -6 C and highs near 3 to 5 C.

THE FURTHER OUTLOOK seems to favour a period of chilly but settled weather that might feature rather severe frosts especially if any snow cover builds up over the weekend. Somewhat milder air will likely feed in from the south near the Atlantic coasts. Highs to about New Years Day would be in the range 4 to 7 for most and 7 to 9 in the far west. Lows in that period could be as low as -5 in places although probably closer to -1 C in larger towns and coastal areas.

A few milder days are likely, if the wind doesn't remain in an easterly or northerly direction, leading to mixed wintry precipitation and possibly some storm force winds too, around 4-6 January. If as some guidance suggests an easterly sets in around then, heavy snow would become possible because there is bound to be some energy hitting whatever regime takes control, so in an easterly flow that could be enhanced troughs moving west.

The overall situation for Britain is about the same as all of the above with the exception of a potential for stronger and even locally severe wind gusts on the weekend after Christmas. The London area is probably less likely than most to see any mixing of precipitation, northern England and Scotland have high odds of seeing snow. It all seems to be a day or two later than you might want for any white Christmas dreams or bets.

See yesterday's discussion for North America, things are becoming a lot more active in eastern regions overnight. My local weather on Monday was foggy to start, then partly to mostly cloudy with brief glimpses of blue sky, with scattered showers by afternoon, highs near 8 C. We could have a bit of snow here by Christmas Eve, not much but a coating of 1-2 cms possibly.

UPDATE _ Wed 24 Dec 2014 _ 4:15 p.m.
_______________________________________

The early model runs (GME, GFS) are showing that the low expected on Friday 26th may fail to gain enough latitude to include all of Ireland in its warm sector. The track is shown as being across central Ireland on both versions of GFS and on the GME. This would tend to keep precipitation rather sleety (snow on higher terrain) in northern counties on Friday afternoon-evening and would take away any mild air expected for early Saturday. This would have implications about wind speed and precipitation types on Saturday as well. I will hold off on a full update until other models have shown their hands. Watch for a forecast update then around 7:15 p.m.

Thursday, Christmas Day, 25 December 2014

Forecasts for Ireland


TODAY ... Frosty in some places as the sun rises, and possibly patchy fog in valleys mainly eastern and southern counties. This should gradually clear to sunshine that will be dimmed by afternoon high cloud, but parts of west Munster will be cloudy all day. The northwest could see a few more wintry showers and these could leave traces of snow on higher ground. Highs 5-7 C.

TONIGHT ... Some clear intervals in central and northeastern counties, frost and fog developing, lows there about -3 C. Cloudy elsewhere, isolated wintry showers, lows 2-4 C.

FRIDAY (St. Stephen's Day 26th) ... Rain will edge into the southwest after midnight and will slowly overspread the rest of Munster and south Leinster during the morning, with fog and a cold southeast breeze keeping temperatures around 5 or 6 C. Further north, mainly north of a Galway to Dublin line but including higher terrain south of that, mixed rain and snow, with snow possibly dominant over some areas to leave 3-5 cm accumulations by evening. This is more likely on hills and in parts of inland northern counties but as the system is very close to the rain-snow dividing line and the models have been backing off a milder solution, keep in mind that this could turn out to be a surprise snowfall event more widely than many anticipate. Highs in the north will struggle to reach 4 C and if it starts snowing temperatures will likely fall back to 0.5 or 1.0 C. There may be fog and freezing drizzle mixed in with this northern sleet and winds while not very strong will be unpleasantly chilly from the east backing into the north as the depression moves past Dublin by evening.

FRIDAY NIGHT into SATURDAY ... Rain or drizzle in the south could change to sleet then wet snow, and snow will intensify for a time on hills while ending in the north. Lows about -2 C north to +2 south. Then the day may feature alternating cloud and sunny intervals with passing wintry showers, a cold northeast to north wind, and a late day band of sleet or snow, with highs possibly about 5 C in sunshine but temperatures would fall to 2-3 C in times with sleet or snow.

SUNDAY to TUESDAY will be generally clear to partly cloudy and cold, although not severely cold -- nights may see isolated readings of -5 or -6 C but -2 C might be more typical. Days will manage to climb to about 4 to 6 C. However parts of the Atlantic coastal counties will enjoy their traditional milder southerly breeze that will not make much progress east of Galway to Cork. Highs there could reach 9 C.

As WEDNESDAY (New Years Eve) and THURSDAY (New Years Day) are high travel days, stay tuned because there may be active weather returning from the southwest in the form of wind and rain, highs would be near 10 C.

FRIDAY 2 January is currently being shown as a more settled day between storm systems under a strong but transient high pressure centre, so it could turn quite a bit colder briefly (highs near 5 C) but expect that to transition back to mild, wet and windy by about 4th or 5th and that may lead to about a week of rather stormy weather as the Atlantic begins to fight with massing cold air over Iceland and parts of Scandinavia. Many forecasters seem to feel that this winter will eventually turn a lot colder and certainly there is no shortage of arctic air to be found, and a healthy ice cover, what's been missing so far is stratospheric warming to get high pressure in a good place for western Europe. Instead much of the cold air has been situated in other portions of the hemisphere.

The weekend weather system will bring a mixture of rain, sleet and snow to Britain, the dividing line will be generally from north-central Wales to north of London but elevation will play a role too. The storm becomes somewhat more intense by early Sunday as it moves across the southern parts of the North Sea into Belgium.

Over North America, there has been a widespread rainfall with very mild temperatures in eastern regions. Somewhat colder air is replacing that today but not until after morning temperatures hit 15-17 C in the larger cities (daily records are closer to 20). It's closer to normal in the Midwest and northern plains states and turning colder in western Canada. My local weather was bright and chilly with shower clouds over the north shore mountains nearby, probably dropping hail or snow up above my elevation. Highs down near sea level were about 6 C.

Once again, enjoy your Christmas Day celebrations and we'll reconvene at this same time on Friday morning to see where the ever-changing low is actually going to land (current track looks like north Clare through Offaly into Wicklow but frontal bands will be somewhat diffuse and I still think Galway to Dublin would be a good dividing line for types of precipitation as it moves through).

Saturday, 27 December, 2014

Forecasts for Ireland


ALERT for wintry showers becoming more widespread later today, and (over the next three or four nights) severe frosts all leading to icy roads at times.

TODAY ... Variable cloud with outbreaks of showery rain, hail or snow. The air aloft will be getting colder which may turn more of these over to snow in northern and central counties by afternoon and early evening. Cold with moderate northwest to north winds 40-70 km/hr, turning slightly to northeast at times -- this could bring Irish Sea streamers onto the Wicklow coast if not as far north as Dublin, precipitation in these will likely be rain near sea level, hail or snow higher up. Highs about 5 or 6 C, but temperatures likely to fall to about 2-3 C in heavier wintry showers.

TONIGHT ... Wintry showers becoming more isolated then ending, clearing, severe frost and patchy ice fog, drive with extreme caution. Lows -6 to -3 C.

SUNDAY ... Persistent freezing fog in some areas, wintry sunshine elsewhere, highs struggling to reach 4 or 5 C for most (7-9 C Atlantic coasts). Persistent ice fog could keep one or two places near 0-2 C. Winds light or calm.

MONDAY ... Severe morning frost and fog, lows -7 to -4 C. Somewhat less fog should persist and it will slowly become a bit milder, highs 5-7 C.

TUESDAY ... Another sharp frost with local ice fog, lows -5 to -2 C. Then partly cloudy, somewhat milder especially in western counties where highs may reach 9 or 10 C. Still about 6-8 C in east.

WEDNESDAY (New Years' Eve) and THURSDAY (New Years' Day) will be breezy and mild with some rain likely, although perhaps not all that much, with temperatures generally much milder in the 7-10 C range.

Another frosty high will develop but it won't be as severe a frost on mornings of 2 and 3 January by the looks of most guidance, about -2 C with days around 7 C. Then we enter a possibly quite volatile and stormy period around the 4th to 7th of January. Storms may have fairly cold air masses entering their circulations and showers from them could be quite mixed.

Britain has seen some outbreaks of heavy snow from the departing storm, mainly in the Midlands and inland southeast. From now on the pattern there will become similar to the above with severe frosts and ice fog developing for several nights. Only western Scotland will see much relief from this before New Years Eve as southeast England stays under the cold high pressure area longer.

Over North America, Christmas and Boxing Day as we also call it over here have been unseasonably mild in much of the U.S.A., and eastern Canada, closer to normal but somewhat on the mild side in western Canada, but here on the west coast it was a bit below normal with highs near 5 C under cloud.

Monday, 29 December, 2014

Forecasts for Ireland


TODAY ... Very cold with persistent frost and some ice fog (clearing latest in parts of the inland southeast), some areas breaking into wintry sunshine, highs around coasts may reach 5-7 C but some inland locations may be challenged to reach even 2 degrees. Secondary roads may be very icy and with some poor visibility added, drive with extreme caution.

TONIGHT ... Once again some severe frost and fog in parts of the inland southeast with lows near -4 C, but somewhat milder elsewhere, or becoming milder towards early morning, temperatures either steady or slowly rising in the range of -1 to +3 C.

TUESDAY ... Low cloud or fog for a time in parts of the east and south, then variable cloud, some sunshine in the mix, but mostly cloudy further west, slowly increasing southerly breezes bringing milder air. Highs 4-7 C east and about 8-10 C west.

WEDNESDAY ... Periods of rain and milder, moderate south to southwest winds, morning lows 3-5 C and afternoon highs 8-12 C mildest in south and west. New Years' Eve will likely see most of the rain clearing away and a rather blustery but mild southwest wind, temperatures at midnight about 8 to 10 C.

THURSDAY, New Years' Day will continue breezy to windy and mild, one or two showers but some long dry intervals, gusts to 80 km/hr. Highs 8-10 C north and 10-12 C south.

FRIDAY will become much colder again with scattered wintry showers more frequent in the north, morning lows 0-2 C and afternoon highs 3-7 C.

SATURDAY 3rd is then expected to become milder with rain, and SUNDAY 4th could see some moderate to strong southwest to west winds. Highs over this weekend around 9 C.

A stormy interval may follow, details are unclear at this point but some severe gusts may develop around 6th or 7th of January with temperatures in the range of 5 to 7 C.

Over most parts of Britain, it will be a similar forecast with the severe frost slowest to clear away from the inland southeast although pockets of similar cold will persist in a few valleys further north. There could be some locally severe icy road conditions as a result. However, it will be easier travel by the period of 31 December to late 1st January.

In North America, much colder air is finally making another push south after taking a vacation for most of December, and the departures from normal (into the -20s or -30s) are greatest over portions of the Rockies and high plains, but the colder air gradually filters out towards the eastern seaboard also, dropping a few degrees each day and ending up below -4 C there by New Years. My local weather on Sunday continued mostly cloudy and rather cold although we are not yet into the arctic air mass, and it was around 5 or 6 C while further inland they have dropped below -10 C during the day.

Wednesday, 31 December, 2014

Forecasts for Ireland


Happy New Year -- my next forecast update after this one will appear on Friday 2nd and it may be a bit later than the usual posting time (look for it around 0900h) as we take a trip to the outer coast for New Years. It's possible that you'll find another forecast posted tomorrow if somebody feels inspired.

TODAY will be mild with periods of rain, 10-15 mm on average, and moderately strong winds from south to southwest at 50-80 km/hr. Highs will reach 11-13 C.

TONIGHT will start out with periods of rain and blustery winds, temperatures steady 8-10 C. It should remain very mild at midnight with the rain generally starting to ease. Some clearing will follow, then more rain or drizzle towards morning.

NEW YEARS' DAY will remain mild and windy with occasional rain. There will be a steady slide in temperature after mid-afternoon, from highs of 11-13 C towards 5 C by evening.

FRIDAY will be breezy to windy and colder with showers becoming wintry over high ground and lows 0-3 C, highs 5-8 C.

SATURDAY will have a frosty start especially in Leinster and Ulster, then variable cloud followed by later rain as temperatures recover from near -1 C to +2 C for lows, to highs of about 7 or 8 C.

SUNDAY and MONDAY will be mild with strong southwest winds developing, temperatures in the range of 10 to 12 C. Some gusts to near 100 km/hr will develop.

TUESDAY and WEDNESDAY are likely to be considerably colder but still windy and unsettled. Here, we may be dealing with storm force wind gusts as deeper low pressure moves across the North Atlantic between Donegal and Iceland but so far models have not reached consensus on the track. Temperatures seem likely to be around 5 to 7 C.

Longer range models show further windstorm potential down the road, the main difference from last January seems to be a slightly colder flow on the average.

My local weather on Tuesday was clear and rather cold although the main thrust of this cold wave has gone much further south into the desert regions. We were spared the strong outflow winds as the high of about 1050 mbs crested right over top of us. The high was about 1 deg C and now it's about minus 5.

Enjoy your NYE and we'll reconvene on Friday.

Friday, 2 January, 2015

Forecasts for Ireland

TODAY ... Some sunshine to start in Leinster and east Munster, increasing cloud elsewhere with showers developing, some could become wintry on high ground and hail may fall closer to sea level, as winds continue blustery from the west to northwest at 40-70 km/hr (higher gusts near exposed coasts). Highs about 7 C.

TONIGHT ... Clear intervals, frosty then clouding over with sleet or wet snow changing to rain in the south. Little accumulation away from higher ground, lows about -1 C then rising to near 3 C.

SATURDAY ... Periods of rain (sleet on high ground) and chilly, highs 4-6 C. Some clearing will spread from west by mid-day and the afternoon could be sunny in Connacht, west Ulster and parts of west Munster.

SUNDAY ... Another rather cold start then increasing cloud, milder. Fairly dry until evening. Morning lows near -1 C and highs near 8 C.

MONDAY ... Breezy or windy and mild with periods of rain, highs near 10 C.

OUTLOOK ... Windy and rather cold at times as flow more westerly than the southwest at start of the week. Highs 7-9 C and possible strong or even severe gusts developing mid-week in parts of the north, although this storm may be just far enough to the north to reduce gusts to 80 km/hr (watch for updates). A second windy spell is likely to follow by the next weekend.

Britain will have pretty much the same set of fast-changing events although on a slightly later schedule, most of Saturday will be wet and cold in England and Wales and this could mix with snow on hills and towards southern Scotland.

In North America, unusual cold and snow has now come and gone from the desert southwest region, most of the snow fell at somewhat higher elevations than Phoenix or Las Vegas and mountain ranges in the region have 15-30 cm at least. This storm is pushing northeast today into the plains states and will bring a variety of weather to the Ohio valley and Great Lakes on the weekend, while returning milder southerly winds to the east coast briefly. The storm will be followed by a blast of very cold air that will set off heavy lake effect snow squalls. A secondary disturbance will race southeast and bring 5-10 cm snowfalls to parts of the northeast U.S. around Monday night. Meanwhile the west coast remains cool and dry but temperatures are slowly returning to near normal values, New Years Day was sunny with highs near 5 C around here.

Had a nice break from weather watching and thanks to 200motels for providing a forecast.

Sunday, 4 January, 2015

Forecasts for Ireland

Astronomy note: there's a full moon tonight, and it reaches that exact point at 0454h towards the point where it is setting.

TODAY ... Becoming milder with a mixture of cloud and sunshine, some isolated showers developing in west and north, winds becoming moderate south to southwest. Highs 8-10 C.

TONIGHT ... Cloudy and becoming misty or foggy with drizzle or light rain, lows about 4-6 C.

MONDAY ... Cloudy, breezy and mild, some rain at times (about 5 mm) with highs 10-12 C.

TUESDAY ... Periods of rain, windy, gusts from southwest to about 80 km/hr and highs near 10 C.

OUTLOOK ... Windy most days from mid-week through next weekend, rapid fluctuations in temperatures, very mild at times (11-13 C) around Friday as a deep low passes just north of Ireland, then rapidly turning colder (2-5 C) at some point during the weekend, but things are moving so rapidly that it could be colder mid-day than at night as air masses keep changing. With that will come frequent changes in the type of showery precipitation especially on higher ground. There continue to be very tentative signs of colder weather in general by mid-January.

Roughly the same forecast applies to Britain, but note that this morning most of England is several degrees below freezing and there is fog that may hold temperatures down to mid-day. There could be a few airport delays there as a result.

Meanwhile, in North America a brief mild spell has moved into the eastern states with rain and fog, but much colder air will blast in later Sunday from a source region in central Canada where it is generally below -30 C at this point. The west coast is somewhat on the cold side with a mix of rain, sleet and snow depending on elevation. Most of Saturday here was dry but cloudy and around 3-4 C but now there is sleet falling.

Tuesday, 6 January, 2015

Forecasts for Ireland

TODAY ... Most places dry with a mixture of cloud and sunshine, fast-moving and brief showers over parts of north and west could become wintry on high ground. Moderate westerly winds backing to south-southwest by afternoon, as temperatures recover to about 7 C.

TONIGHT ... Periods of rain developing, temperatures steady near 4 C then rising in west towards morning to about 8 to 10 C.

WEDNESDAY ... Cloudy with periods of rain (10-20 mm for most, but heaviest in northwest). Moderate to strong southwest winds 60-90 km/hr in most regions, 70-110 km/hr in north and west. Highs 11-13 C.

THURSDAY ... Becoming colder during the early morning hours, sleet at times then partial clearing, wintry showers developing mid-day over higher ground, strong westerly winds gusting to 80 km/hr. Lows near 2 C and highs near 6 C.

FRIDAY ... Very windy in the early morning hours especially in Donegal and nearby counties, gusts to 120 km/hr possible there, 80 km/hr elsewhere, as milder air rushes in. Temperatures will rise through the night and level off for much of the day near 13 or 14 C (15-16 is possible in downsloping near the Wicklow coasts). Rain may be heavy (20-30 mm) in parts of the north with spot flooding risks in Connacht and west Ulster, but there will be longer dry intervals in the south. Southwest winds will continue to be strong in the range of 70-110 km/hr.

SATURDAY ... Becoming much colder again after a very windy night with squally showers, then mixed wintry showers developing, westerly winds in the range of 70-120 km/hr north, 50-80 km/hr south. Temperatures steady near 3 or 4 C north, 5 to 7 C south.

SUNDAY ... Still rather cold and unsettled although not quite as windy, temperatures near 5 C.

OUTLOOK ... Colder in general terms next week, unsettled, strong westerly winds at times, and widespread wintry showers especially over higher parts of the north and west. Highs generally about 5 C. A few icy stretches of road are likely in parts of the north. The differences may seem a bit less dramatic in more temperate locations in the south.

Briefly, the forecasts for Britain will follow a similar course and they will see some very mild readings Friday night into Saturday morning there. The strongest winds will likely be across northern England.

In North America, snow is heading towards the east coast from the Midwest early this morning, and Washington DC may see their first measurable falls of the winter (expecting 3 cm south to 8 cm north), while in Philly and NYC amounts could be just 1-3 cm. The system is not very strong at this point but brought 10 cm to parts of the Midwest earlier. The main feature will be bitterly cold air flooding south behind this "clipper" type low, from central Canada where it is about -30 C with -45 wind chills. Meanwhile, milder Pacific air has pushed this cold air back some distance near the coast, and our day turned out very foggy and occasionally rainy with temperatures creeping up to 7 C.

Thursday, 8 January, 2015

Forecasts for Ireland


TODAY ... Bright but cold with moderate westerly winds 50-80 km/hr, sometimes becoming squally especially near Atlantic coasts. Passing showers likely mixing with hail or sleet with snow possible on higher ground. Some sunny intervals more frequent near east and south coasts. Highs 6-8 C.

TONIGHT ... Becoming very windy especially in Connacht and west Ulster, peaking after midnight WSW 70-120 km/hr there, otherwise 60-90 km/hr. Intervals of rain will clear east, temperatures will start to rise towards midnight and may reach 8-10 C during the night.

FRIDAY ... Windy and very mild, with outbreaks of heavy rain (15-25 mm) in northern counties, longer dry spells in south. The strongest winds of early morning will abate slightly then resume afternoon and evening, with gusts to 110 km/hr in north, 90 km/hr south. Highs 13-15 C with the higher values in coastal southeast.

SATURDAY ... Windy and turning steadily colder, temperatures steady near 9 in the early morning hours then sliding down to about 5 C mid-day, with showers turning more wintry especially in north. Winds westerly 60-100 km/hr and large waves likely on Atlantic coasts.

SUNDAY ... Continued rather cold but wind not as strong, passing mixed or wintry showers, morning lows near 1 C and highs near 5 C.

MONDAY ... Early morning rain and milder, briefly, in strong or very strong WSW winds 70-110 km/hr. Temperatures will peak around 8 C then slide down rather quickly to near 2 C by late afternoon.

TUESDAY ... Variable cloud, wintry showers, windy and cold, temperatures in the range of -1 to +4 C and risk of snow accumulating to 2-5 cm in some parts of Connacht and Ulster, mainly above 200m. Wind gusts to 90 or 100 km/hr.

WEDNESDAY ... Current guidance shows potential for even stronger wind gusts developing, details may change but at this point we could say there is a chance of a "level two" windstorm alert and gusts to 130 km/hr in westerly winds. It will remain quite cold too, around 5 C with squally and mixed wintry showers.

FURTHER OUTLOOK ... Very cold towards the end of next week and into the following weekend (17th-18th), some chance of snow in many areas and temperatures not far from 2 C. How that evolves is not very clear from guidance, which is trying to return to a westerly flow but this could change as there are some signs of a sinking jet stream and the first stages of northern blocking on some charts out beyond ten days.

The windy conditions tonight and Friday night will probably be somewhat more intense for Scotland which will see even tighter gradients developing. Otherwise would expect roughly this same sequence for most parts of Britain.

In North America, the severe cold has enveloped most of the Great Lakes, Midwest and northeastern states, and continues to hold sway in central Canada but parts of Alberta and Montana have escaped for a day or so as a weak frontal wave pushes through. Mild Pacific air is now firmly in control west of the Rockies and it is mainly dry now too. My local weather on Wednesday was very foggy at times, with glimpses of sun around mid-afternoon, and a mild high near 11 C.

Saturday, 10 January, 2015

Forecasts for Ireland

TODAY ... Windy and rapidly turning much colder, with passing showers becoming more wintry especially over Connacht and Ulster, some accumulations of snow possible on hills there and on highest elevations in Munster, Leinster by evening. Showers will contain hail and produce some thunder at lower elevations, but some sunny intervals also. Winds westerly 70-110 km/hr, mid-day temperatures will level off in the range of 3-6 C.

TONIGHT ... Further wintry showers in blustery west to northwest winds, temperatures steady around 1 or 2 C.

SUNDAY ... Not as windy but continuing cold with passing wintry showers, and afternoon highs 7 to 9 C.

MONDAY ... Morning rain with milder temperatures for a few hours (8-11 C) then back into colder and blustery conditions with mixed wintry showers redeveloping, winds westerly 70-100 km/hr.

TUESDAY ... Breezy or windy at times, cold, passing wintry showers with some snow accumulations north and west on higher ground. Lows near -2 C and highs near 5 or 6 C.

WEDNESDAY ... Periods of rain, somewhat milder again, becoming windy or very windy by evening and overnight into early Thursday. Highs 8-11 C. We will be monitoring the potential for a severe windstorm with gusts over 130 km/hr in this general time frame, cannot be too specific about details yet, but most of the more reliable models have very intense winds now for the night of 14th-15th.

OUTLOOK ... Colder again towards end of the week and the following weekend, some wintry precipitation likely. Temperatures will average 2 or 3 degrees below normal in the period 15th to 21st. Beyond that, it seems to be a toss-up whether we see a return to unsettled westerly flow, or something a bit colder and more settled at times.

My local weather on Friday was cloudy with a high near 8 C, light rain has begun this evening.

Sunday, 11 January, 2015

Forecasts for Ireland


TODAY ... Rather cold, passing showers that may be wintry at times on higher ground in particular, winds moderate for a while then becoming strong again later from west to east, reaching SW 60-100 km/hr by evening. Highs 6-8 C.

TONIGHT ... Windy with periods of rain, temperatures steady 7-9 C, some clearing in west by morning, as winds veer SW to W 60-100 km/hr.

MONDAY ... Quickly turning colder again during the morning, showers ending for a while then a new round of wintry showers mainly over western counties, temperatures sliding down to around 5 C or lower, winds westerly 50-90 km/hr.

TUESDAY ... Cold with passing wintry showers, some accumulations of snow may develop in parts of Connacht, Ulster and inland Leinster, higher parts of west Munster. Some sunny intervals too across eastern coastal counties. Morning lows -2 to +2 C and highs only 4 to 7 C. Moderate to strong westerly winds backing into southwest later with gusts to 100 km/hr.

WEDNESDAY ... Windy and somewhat milder with periods of rain. There is some chance of very strong and damaging wind gusts but I am holding off on specifics until models reach better consensus. The chances are probably at least 50-50 that we will need level 2 alerts in some part of the west if not more widely. Highs around 8 C, but turning colder again towards end of the day with rain turning back to mixed and wintry showers, starting in west Munster in southwest winds that may gust over 110 km/hr.

THURSDAY and FRIDAY will remain cold and windy with passing wintry showers and west to northwest winds at about 50-80 km/hr, with highs in the range 3-7 C and lows near -1 C.

THE FURTHER OUTLOOK calls for similar rather cold and unsettled weather with the odd brief milder interval with rain, otherwise mostly colder than average and with continuing risk of snow on higher ground mostly.

My local weather was cloudy with light rain and highs near 7 C.

Tuesday, 13 January, 2015

Forecasts for Ireland


ADVANCE ALERT -- snow may become fairly widespread at times today and tonight, amounts will be generally 1-3 cm and at lower elevations snow will probably melt, but higher roads may become icy at times -- very strong winds are anticipated on Wednesday and overnight into early Thursday. The first wave will hit the south and west coasts with gale force southerlies on Wednesday afternoon, gusts to 120 km/hr are possible. A second wave will be more concentrated on northwest and west-central coasts and gusts to 140 km/hr are possible. There is a 25% risk that these values could be exceeded by 20 km/hr which would turn isolated or moderate damage into more substantial damage impacts.

TODAY ... Windy and very cold with outbreaks of sleet, wet snow and (at coastal elevations) rain. Highs 2-6 C. Winds SW 50-80 km/hr will add more of a chill, feeling like zero to -3 C. A few sunny breaks may develop in eastern counties.

TONIGHT ... Windy with intervals of snow or sleet, cold with lows near -1 C to about +2 C in some coastal areas. Winds backing more to south towards morning, 50-80 km/hr. Icy roads where untreated.

WEDNESDAY ... Stormy at times as winds increase from south around mid-day to reach 80-120 km/hr, periods of rain becoming heavy, some embedded thunderstorms. Highs near 8 C.

WEDNESDAY NIGHT into THURSDAY MORNING will continue very windy after perhaps a brief lull in some parts of the south and east, with the strongest winds now felt from Clare to Donegal and some distance inland, westerly around 90-140 km/hr. Some tree damage is likely. Elsewhere, wind speeds will be 80-120 km/hr but lower in some sheltered inland districts. Rain may turn to sleet, hail or snow as temperatures gradually fall off from about 6 C in the evening to 2 C by morning.

THURSDAY will continue windy and cold with passing wintry showers, some accumulations of snow on hills mainly, and winds WNW 50-80 km/hr for most, after a morning peak still around 110 km/hr in the north. Highs 4-6 C.

FRIDAY to SUNDAY will be a cold, generally bright period with passing wintry showers, some risk of accumulating snows on hills, and sharp morning frosts, lows near -2 C and highs 3-7 C. This may lead to some poor driving conditions in parts of the inland north in particular and higher areas elsewhere.

MONDAY could see a brief return to rain and near normal temperatures of about 7 C then turning colder again with mixed wintry precipitation ...

FURTHER OUTLOOK ... then, the Atlantic appears to be losing a battle with the arctic for control of this sector of the atmosphere and by next week, colder air masses from Scandinavia may be trying to push back the frontal zone and direct cold, possibly snow-producing northeast winds towards Ireland. The chances are greater that this will reach Britain and perhaps stall for a time around east Ulster leaving other parts of Ireland in slightly above freezing transitional air masses with mixed sleety precipitation, but if the fronts do eventually push far enough south and west, snow could develop. Different models have different rates of forward movement for this colder air so trying to specify what day(s) it might snow is difficult, the chances seem to increase moving forward.

For Britain would expect similar outcomes, on Wednesday night the south will see gales from the southwest and early Thursday the westerly storm force winds will strike parts of north-central England and southern Scotland with gusts perhaps over 150 km/hr. As mentioned, if and when the colder air masses intrude from the northeast, snow will be more likely to begin first in eastern Britain from the North Sea.

In North America the weather pattern is generally quiet and cold now, with remnants of yesterday's mixed precip moving out of New England and eastern Canada. The developing storm for Ireland is already off the east coast of Newfoundland now. Meanwhile, my local weather was cloudy and mild with fog and light rain, highs near 7 C.

WATCH FOR UPDATES AS NEW GUIDANCE IS ASSESSED FOR THE STRONG WIND EVENT TOMORROW. WILL UPDATE BRIEFLY LATE AFTERNOON, EVEN IF NO CHANGES IN FORECAST.

UPDATE (2) _ Tues 13 Jan 2015 _ 11:55 pm
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No essential changes in forecast, in general terms this appears to be very close to the borderline between level 2 and level 3 that we use here on Boards, at least for the west and northwest coasts, and a solid level 2 event almost everywhere else.

I will be posting a fairly early forecast shortly after 0630h given the severity, and perhaps editing in some of the less urgent stuff between 0730 and 0800, so you may find a rather abrupt end to the forecast if you happen to look in early. Check back later for the full package and expect at least one pre-onset update as well as the ongoing very valuable discussion in the storm thread (where the real experts are hiding out).

Here are my late evening over/under maximum gust predictions for various locations around Ireland.

Malin 83, Mace 80, Belmullet 80, Finner 67, Knock 55, Shannon 64, Valentia 62, Sherkin 64, Cork 60, Waterford 57, Dublin 62, Casement 59, Mullingar 48, Oak Park 42, Aldergrove (Belfast) 60, Eglinton (Derry) 64. The uncertainty would be plus or minus 10. For km/hr, multiply by two and then reduce by 10% (e.g. 80x2 = 160, less 16 = 144).