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Potential for wind and snow (NW) 4th, 5th December - DISCUSSION ONLY
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JanuarySnowstor wrote: »Let's wait and see before criticising.
I believe all the credentials are there for a fall of snow Sunday night.
Ok maybe it wont lie but I have a feeling many will be surprised & the reason this board is quite is because the Easties are not favoured in this kind of setup.
Snow for Cork sun night, that's my prediction:)
Looks marginal at best , but I am hoping it comes off for you folks ! But unless there is some serious upgrades I dont see it happening , Even the snow risk charts which are notorious does not give much cover and anything they do cover is at 400mtrs
A rain to snow event , but I expect it would be hill snow
Best chance is Sunday night into Monday morning .
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The GFS gramets below for Sunday afternoon to Monday night show mostly rain in the Met Éireann stations, with the odd flurry of snow at one or two. I think we could see the winter snow competition decided Monday, as I reckon Knock will come in with a snow report (as long as it falls during the observers' shift, or else we'll never know!). The GFS forecast sounding for Finner for 09Z Monday shows dewpoints below zero all the way, with 850 theta-w around +1 °C and 850-1000 thickness 1290-1300 dam, which with SLP around 1000 hPa, would translate to snow to around 100 m, but maybe to lower levels due to turbulent mixing from above.
I think these conditions will prevail for much of northern Connaught, Ulster, and north Leinster, although these sea-effect showers will die out as they cross eastwards across the country. We should see decent hail in the north, with the possibility of our friend Herr Graupel in other areas.
Malin Head
Finner
Ballyhaise
Knock
Casement
Shannon Airport
Johnstown Castle
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WHATS GRAUPEL????? .... :rolleyes::rolleyes::rolleyes:
For those who don't know it was the weather word of '2010' in Ireland.
Here is a post that Su Campu did on 02 December 2010.
Over the past few days there have been many people wondering what this term "graupel" is, writes iWeather Online's Fergal Tierney.
Graupel is simply a snowflake which has a layer of ice, or rime, around its surface. It may look like hail, but on closer inspection you will see it is less dense, and may fall apart on handling. Graupel is the German term for it, but it is also known as soft or small hail, and will appear as GS in METARs (routine aviation weather reports from airports).
METAR from Dublin Airport, 1530, November 30th, reporting a recent graupel shower - EIDW 301530Z 06013G24KT 8000 -SHSN FEW004 SCT020CB BKN050 01/M02 Q1018 RESHGS TEMPO 9999 10290095=
In the atmosphere, water can exist in liqiud form, even at temperatures down to -40°C. This is known as supercooled liquid. If there is some condensation nucleus present - a snowflake, for example - this supercooled water will instantly freeze on its surface and form a layer of rime ice over it. This will transform the snowflake from its normal "fluffy" appearance to a particle more similar to a hailstone. This is what has been falling in many parts of the east over this cold spell, and has led to the widespread curiosity around it.
So why have we got so much graupel? As I explained in my article on Lake-effect Showers last week, the warm Irish Sea is generating enormous updrafts throughout the cumulonimbus clouds, and these are dragging snowflakes from lower levels into mid-upper levels, where the supercooled liquid is present. Here they get coated and hence more dense, and cannot be supported by the updrafts anymore, thus falling to earth as the famous graupel particles. In most cases, graupel will occur at the leading edge of the snow shower, with more snowflakes or hail falling as core of the shower passes over.
So what's the difference between hail and graupel? Hail is formed by a slightly different process. Supercooled liquid accretes around a condensation nucleus, growing in size as more and more rime freezes around the particle as it bounces up and down in the cloud's updrafts. Eventually it becomes too heavy for the updrafts and falls to earth. If you cut open a hail particle you will see it has layers, like an onion. Graupel will have a snowflake, but it will probably fall apart when you try to cut it!Over the past few days there have been many people wondering what this term "graupel" is, writes iWeather Online's Fergal Tierney.
Graupel is simply a snowflake which has a layer of ice, or rime, around its surface. It may look like hail, but on closer inspection you will see it is less dense, and may fall apart on handling. Graupel is the German term for it, but it is also known as soft or small hail, and will appear as GS in METARs (routine aviation weather reports from airports).
METAR from Dublin Airport, 1530, November 30th, reporting a recent graupel shower - EIDW 301530Z 06013G24KT 8000 -SHSN FEW004 SCT020CB BKN050 01/M02 Q1018 RESHGS TEMPO 9999 10290095=
In the atmosphere, water can exist in liqiud form, even at temperatures down to -40°C. This is known as supercooled liquid. If there is some condensation nucleus present - a snowflake, for example - this supercooled water will instantly freeze on its surface and form a layer of rime ice over it. This will transform the snowflake from its normal "fluffy" appearance to a particle more similar to a hailstone. This is what has been falling in many parts of the east over this cold spell, and has led to the widespread curiosity around it.
So why have we got so much graupel? As I explained in my article on Lake-effect Showers last week, the warm Irish Sea is generating enormous updrafts throughout the cumulonimbus clouds, and these are dragging snowflakes from lower levels into mid-upper levels, where the supercooled liquid is present. Here they get coated and hence more dense, and cannot be supported by the updrafts anymore, thus falling to earth as the famous graupel particles. In most cases, graupel will occur at the leading edge of the snow shower, with more snowflakes or hail falling as core of the shower passes over.
So what's the difference between hail and graupel? Hail is formed by a slightly different process. Supercooled liquid accretes around a condensation nucleus, growing in size as more and more rime freezes around the particle as it bounces up and down in the cloud's updrafts. Eventually it becomes too heavy for the updrafts and falls to earth. If you cut open a hail particle you will see it has layers, like an onion. Graupel will have a snowflake, but it will probably fall apart when you try to cut it!0 -
MTC/Peter O'Donnell
SUNDAY ... Variable cloud, cold, windy (WNW 25-45 mph) with passing wintry showers more likely to be rain near east or south coasts but quite often hail or snow elsewhere. Highs 5-8 C. Some accumulating snow by afternoon and evening in parts of Ulster and north Connacht, mainly above 150m asl with potential for 3-5 cms overnight into Monday in some higher areas.
MONDAY ... Breezy to windy, cold, passing wintry showers, lows near 1 deg and highs near 6 except a range of 3-9 south coast and in Dublin city. Once again, the chance of rain showers would be higher in those milder districts. An interval of steady snow may develop in parts of the north later in the day.
TUESDAY ... Less windy with passing wintry showers, lows near -1 C and highs near 6 C.
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Met Eireann
Colder tomorrow Sunday with widespread blustery showers, turning wintry in the northwest towards evening. Bright or sunny intervals too though. Highest temperatures just 4 to 8 degrees, in a mostly fresh westerly wind.
Sunday night: Snow showers over parts of Ulster; clear spells elsewhere and just scattered wintry showers. Lowest temperatures from -1 degrees (Leinster) to +4 degrees (west coast and southwest coast) with a sharp to severe ground frost away from Atlantic coasts. Monday: Good sunny spells; scattered rain, hail or sleet showers in parts of the west and north. A cold day with highest temperatures on Monday only 3 to 7 degrees in fresh to strong westerly winds. Another cold night Monday night with air minima away from Atlantic coasts again down to zero or -1 degrees with a sharp to severe ground frost. Some wintry showers possible in parts of the northwest but most areas dry.
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UK Met Office
Tonight:
Blustery showers for Scotland, Northern Ireland and northern England, wintry over hills and down to lower levels across Scotland. Elsewhere dry with clear spells. A touch of frost in places.
Sunday:
Remaining cold across northern UK with further showers, often heavy with snow over the hills and to lower levels across Scotland. Elsewhere sunny spells, with some rain in the south.
Outlook for Monday to Wednesday:
Rather cold in the north with a continuation of blustery showers, wintry over the hills and to low levels in Scotland. Elsewhere, sunny spells with some rain at times.
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Netweather
Sunday will see further sunny intervals and wintry showers for Scotland, Northern Ireland and northwest England - with hill snow and snow falling to lower levels across Scotland. More in the way of cloud than today across Wales, central, southern and eastern England, with some rain for southern counties, though probably staying dry and bright for The Midlands and eastern England.
Into next week, Monday will be bright but will feel rather chilly everywhere in the brisk northwesterly wind, more particularly across the north where we will continue to see those wintry showers falling as snow to lower levels across Scotland. For the rest of the week it looks like remaining cold in the north with further wintry showers falling as snow over the hills and to lower levels across Scotland, less cold with rain at times further south.
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The Weather Outlook
The unsettled spell of weather will continue through the weekend with all parts of the country seeing further showers or longer spells of rain at times. In the south it will be quite mild on Saturday, but it will become colder in the north with an increasing risk of sleet or snow showers over higher ground. Temperatures will tend to lower at times during the coming week, and this will bring a risk of some sleet or snow to lower ground in northern regions, and even the possibility of a wintry mix over higher ground further south on some days. Although the wintry conditions will be mostly transient, and for most of the country nothing like the bitter cold we experienced last December, there is the potential for excellent early season conditions in the Scottish ski resorts in the run up to Christmas.
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Weatheronline.co.uk
Another windy day across Britain with gales developing in the west as rain spills in across all but central and eastern parts of England. Feeing cold out there today with highs of 6 to 9C.
Very windy with gales and rain across the country through the evening but this sweeps away from all but the far south of England. It turns colder tonight as rain showers turn to snow across Scotland. Lows of 5 to 10C north to south.
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Mark Vogan
Increasingly cold northwest flow may present first low level snowfall of season to Northern UK by early Sunday/Mon
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From UK Weather wordpress blog (note advisory for Antrim and Down).
Valid: Sunday 4th – Tuesday 6th December 2011
As we move through the course of today, through Sunday and into Monday, an area of Low Pressure pushing Eastwards to the North of Scotland will allow much colder air to push in behind it.
As the system pushes Eastwards, winds will become more North-Westerly and due to the colder air that will be in place, snow showers will begin pushing into Northern and Western areas. Whilst some of these showers are likely to heavy, severe disruption isn’t considered severe enough for a weather warning, so an advisory has been issued.
Due to the direction and strength of the wind, showers may well become fairly frequent and could push further inland across some parts. Accumulations down to lower levels are unlikely to amount to much more than 2-5cm, higher ground such as the Scottish Highlands may see snowfall accumulations of up to 10-15cm. As we move through Monday and into Tuesday, snowfall will generally become more confined to higher ground.
Whilst the key areas have been highlighted in yellow on the map above, surrounding areas may see one or two snow flurries, but the risk is considered fairly low.0 -
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Random....and interesting, thanks for sharing Pangea
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I think things are still looking as they have been pretty much all along this week, and there's very good agreement between the models for the period tomorrow through to Tuesday.
Widespread heavy showers of hail and sleet will move in off the Atlantic to the north, west and southwest, dying fairly quickly as they move eastwards. We should see some more organised bands of showers or comma features form over the ocean as upper temperatures cool (-35 °C T500), but these should only affect the northwest and north. I would still say some showers will fall as snow above around 100 m north of around Mayo to Meath, possibly lower in western Ulster, and around 200-250 metres in the south.
500-1000 thicknesses will range from 528 dam in the south to around 522 dam in the extreme north during Monday. 522 dam would normally be the threshold for snow at all levels, but partial (850-1000) thickness, which is a more important quantity, looks like being a little too high at 129.5 - 130 dam. This and the +1 to +2 °C 850 theta-w and +12 - 14 °C 850 theta-e values forecast look like preventing snow to all levels.
There looks like a possibility of a more organised period of snow in the northwest Monday night and into Tuesday morning as a small warm front comes up against the cold air (shown below). This would be brief, turning more sleety as warm air advection takes hold.
After that, there are no strong signs that the end of the week will be any colder than Monday, and the latest guidance shows a strong low moving into the North Sea, bringing the coldest air with it, and away from us.0 -
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