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Cold Spell Discussion cont: Tuesday, Wednesday - more heavy snow risk

  • 21-02-2010 11:05am
    #1
    Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    Next days to watch are Tuesday and Wednesday. The far South of the country may escape with just rain but the rest of the country is at risk of some heavy snowfall (far more then last night). Discuss the prosects.

    100221_0000_66.png

    100221_0000_66.png

    100221_0000_72.png

    100221_0000_72.png

    fax72s.gif


    GFS has prospects further North over Ulster whilst the ECM has it further South principally over Leinster. UKMO has a happy medium. Things will chop and change over the next 24hrs but big potential on Tuesday/Wednesday.


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Comments

  • Registered Users Posts: 798 ✭✭✭Bicycle


    Sadly it would appear that the "No Snow Zone" over Limerick continues to remain in spite of us no longer having a "Great Defender" :p

    Enjoy the snow, those of you who have it.


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 17,595 Mod ✭✭✭✭DOCARCH


    Looking really interesting atm but another close call, probably another nowcast situation (as ever).

    BTW DM2, love the way you say the south may 'escape' with just rain! :D Some sort of consolation for them? Like how could anybody want snow? :D


  • Registered Users Posts: 8,913 ✭✭✭Danno


    The last fax chart posted above would be of serious concern as the 528dam line is too far north, especially with a system that comes up from the south.

    If the centre of that low was shunted further east, effectivley closing the Biscay route and drawing in air from France via England, Wales then us, I'd be a little more confident...

    Unless the models come up with something better, then i'd say no to this one DM2.


  • Registered Users Posts: 8,913 ✭✭✭Danno


    The BBC Weather for The Week Ahead will feature within the Country Tracks program around 11.45am to 11.50am (in around 5 or 10 minutes) on BBC1 today. Sky Channel 141.


  • Closed Accounts Posts: 2,693 ✭✭✭Redsunset


    poor country track forecast


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  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    redsunset wrote: »
    poor country track forecast

    I would not take too much notice of that. It's a marginal situation with a few miles being the difference between rain and snow. The 00z GFS, for example, had widespread snowfall Wednesday night and the ECM does not agree with the UK Met Office on the posistioning of Low Pressure which makes a really big difference to the prospects.


    Looks like either way Ulster is gauranteed a hammering on Tuesday and Wednesday.


    BTW the 06z GFS, whilst it brings snow for a time to many areas on Tuesday, is actually on the mild side of the ensembles (the thick green line). The average (the thick white line) indicates more wintry conditions then the op run.

    MT8_Dublin_ens.png


  • Closed Accounts Posts: 2,693 ✭✭✭Redsunset


    Oh i know its not gospel and will swing to and fro and will end up being a nowcast i feel.

    As for the north like you said,the UKMO sure have some confidence for wintryness.


    Northern Ireland: Co Antrim
    Co Armagh
    Co Derry
    Co Down
    Co Fermanagh
    Co Tyrone
    Heavy Snow Wed 24 Feb
    There is a moderate risk of severe weather affecting parts of the UK. Rain spreading north may turn to snow and has the potential to give accumulations of more than 15 cm of fresh snow in places.
    Issued at: 1042 Sat 20 Feb


  • Registered Users Posts: 3,736 ✭✭✭ch750536


    darkman2 wrote: »
    Next days to watch are Tuesday and Wednesday. The far South of the country may escape with just rain but the ...

    What do you mean, escape?


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    ch750536 wrote: »
    What do you mean, escape?


    They could have a more pleasant commute to work on Wednesday then areas further North.;)


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    redsunset wrote: »
    Oh i know its not gospel and will swing to and fro and will end up being a nowcast i feel.

    As for the north like you said,the UKMO sure have some confidence for wintryness.


    Northern Ireland: Co Antrim
    Co Armagh
    Co Derry
    Co Down
    Co Fermanagh
    Co Tyrone
    Heavy Snow Wed 24 Feb
    There is a moderate risk of severe weather affecting parts of the UK. Rain spreading north may turn to snow and has the potential to give accumulations of more than 15 cm of fresh snow in places.
    Issued at: 1042 Sat 20 Feb


    This is what the UKMO shows precip and temperature rise. Clearly North Leinster and Ulster in the firing line. But further south too. Places like Dublin for example - alot of precipitation and temperatures 1 - 3C.

    U72-594.GIF?21-06

    U72-580.GIF?21-06


    But it will change over the next few runs. Risk could be further South or further North.


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  • Closed Accounts Posts: 5,550 ✭✭✭Min


    Hope we escape, I hope Dublin doesn't get snow either since that would be a national disaster ;)

    That said, we had snow last night while in Kilkenny city they had none, so one never knows.


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 17,595 Mod ✭✭✭✭DOCARCH


    Sorry misread post above - no comment!




  • darkman2 wrote: »
    This is what the UKMO shows precip and temperature rise. Clearly North Leinster and Ulster in the firing line. But further south too. Places like Dublin for example - alot of precipitation and temperatures 1 - 3C.

    U72-594.GIF?21-06

    U72-580.GIF?21-06


    But it will change over the next few runs. Risk could be further South or further North.
    The country tracks forecast on BBC one had rain for everywhere south of Ulster and bits of north connaught.
    Any class of an East wind coming in off the irish sea with no real cold source and with a positive dewpoint will ensure rain in Dublin below 800ft asl.




  • redsunset wrote: »
    poor country track forecast
    Indeed.
    What darkman2 is not taking into account is that winds from the irish sea with no lengthy cold surface feed,will bring in positive dewpoints.
    Thinking otherwise I'm sad to say is dreaming.

    Remember the famous sunday snow in the early january spell, that cork got but we didn't get on the East?
    Twas a lot colder then than it is now and it rained due to the positive dewpoints/warmer air advection from the irish sea ie no real cold source left.

    Lets not let dreaming over rule basic weather science.

    That low pressure going a few 10's of miles north or south of where it is will change who gets snow on high ground and 20 miles plus inland but it will not make a half worth of difference on the coast in the East.


  • Closed Accounts Posts: 1,576 ✭✭✭patneve2


    Indeed.
    What darkman2 is not taking into account is that winds from the irish sea with no lengthy cold surface feed,will bring in positive dewpoints.
    Thinking otherwise I'm sad to say is dreaming.

    Remember the famous sunday snow in the early january spell, that cork got but we didn't get on the East?
    Twas a lot colder then than it is now and it rained due to the positive dewpoints/warmer air advection from the irish sea ie no real cold source left.

    Lets not let dreaming over rule basic weather science.

    That low pressure going a few 10's of miles north or south of where it is will change who gets snow on high ground and 20 miles plus inland but it will not make a half worth of difference on the coast in the East.

    You also have to take into account the fact that SSTs are about 1.5 to 2 degrees colder now than in the Jan cold spell (m2 Buoy is @ 7.6 degrees).


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    Indeed.
    What darkman2 is not taking into account is that winds from the irish sea with no lengthy cold surface feed,will bring in positive dewpoints.
    Thinking otherwise I'm sad to say is dreaming.

    Remember the famous sunday snow in the early january spell, that cork got but we didn't get on the East?
    Twas a lot colder then than it is now and it rained due to the positive dewpoints/warmer air advection from the irish sea ie no real cold source left.

    Lets not let dreaming over rule basic weather science.

    That low pressure going a few 10's of miles north or south of where it is will change who gets snow on high ground and 20 miles plus inland but it will not make a half worth of difference on the coast in the East.

    Nonsense. Im well able to read the charts and take all factors into account. For example if you don't think the ECM charts above would bring an appreciable amounts of snow to Eastern coastal counties then I don't think you are reading the charts properly and seem unfamiliar with the dynamics surrounding a frontal event. We don't need a cold air source - the cold air is already over us and that won't change until the fronts clear through - which won't happen incidentally. Dew Points should remain around 0C generally or a little below. (Away from Southern and maybe Southeastern areas but that's uncertain)


  • Closed Accounts Posts: 5,550 ✭✭✭Min


    Snow risk this week - south and east according to Evelyn.




  • darkman2 wrote: »
    Nonsense. Im well able to read the charts and take all factors into account. For example if you don't think the ECM charts above would bring an appreciable amounts of snow to Eastern coastal counties then I don't think you are reading the charts properly and seem unfamiliar with the dynamics surrounding a frontal event. We don't need a cold air source - the cold air is already over us and that won't change until the fronts clear through - which won't happen incidentally. Dew Points should remain around 0C generally or a little below.
    Even Evylyn just now mentioned "away from the coasts" darkman2.

    I see so you think that the less cold air coming in off the sea with higher dewpoints is somehow going to magically deliver snow when colder 850's last january [the day cork got its snow as it had a land breeze] delivered rain?

    I'd like to borrow your magic wand please with all due respect because thats what I'll need :)

    The risk is for high ground and well inland.


  • Registered Users Posts: 1,115 ✭✭✭Takeshi_Kovacs


    Do ye think higher ground in southwest will get more snow, there's a substantial thaw on at the moment, especially on sunnier slopes. I am hoping to get out next weekend and do some hiking, and would be nice if there was some left.


  • Registered Users Posts: 2,876 ✭✭✭JanuarySnowstor


    Indeed.
    What darkman2 is not taking into account is that winds from the irish sea with no lengthy cold surface feed,will bring in positive dewpoints.
    Thinking otherwise I'm sad to say is dreaming.

    Remember the famous sunday snow in the early january spell, that cork got but we didn't get on the East?
    Twas a lot colder then than it is now and it rained due to the positive dewpoints/warmer air advection from the irish sea ie no real cold source left.

    .
    I think your pbly right, the air isnt cold enough midweek to prevent coastal areas of the East seeing rain. Uppers would want to be at -10 not flirting -5's, with thickness's also margnal. I would think the North midlands is at risk, that's about it.
    Also Dublin city holds in a little heat which was demonstrated last night when places like Swords and Naas got a lot more than Dublin city.

    As for the South, we are the wrong side of marginal all week with little chance of falling snow. Bitterly cold nights to come though which sums up this incredible Winter i.e freezing cold yet very little snow!


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  • Closed Accounts Posts: 5,550 ✭✭✭Min


    Met Eireann seem to be using charts with white for snow now, maybe I missed them before but yeah it looks like snow for inland areas of the east and south.


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    Even Evylyn just now mentioned "away from the coasts" darkman2.

    I see so you think that the less cold air coming in off the sea with higher dewpoints is somehow going to magically deliver snow when colder 850's last january [the day cork got its snow as it had a land breeze] delivered rain?

    I'd like to borrow your magic wand please with all due respect because thats what I'll need :)

    The risk is for high ground and well inland.


    No, she did not mention, "away from the coasts" - even if she did I don't particularly need to pay attention to what she says anyway considering the charts are right in front of us.

    The setup coming is very different to the one you are referencing. Firstly SST's are at the lowest point of the year. Secondly the rotation is taking precipitation out of the UK where it will also be snowing. Thirdly 850 temps of -4 or lower are all that are required in a frontal event as things like evaporative cooling take place. You want to reference an event - then take a look at the 1982 statistics. If that was progged tomorrow you would no doubt be talking about the wind off the sea. 850 temps where -4 generally and sub -5 to the North. The temperatures progged in the Irish Sea by the UKMO are 2 or 3 degrees in the North Irish Sea, 4 or 5C further South. 2 or 3C and sub zero dew points over the sea is not magically going to turn the snow from Britain back to rain like a click of a finger. It may be different closer to where you are as SST's may be slightly higher there (again it's very uncertain) but here the UKMO progs temps 1 - 3C, Irish Sea temps 2 or 3C and 850's at -4 along with persistent precipitation. Not that I think the UKMO is cert to come off. All the models are contradictory to some extent atm. So in this case this argument is elementary because things are so marginal as regards posistioning that a few miles here or there is the difference. But I don't support this theory of yours that a wind off the Irish sea automatically = no snow. Clearly it does not. And probrably won't on Tuesday either especially further North up the coast.



    66-574.GIF?21-6


    66-101.GIF?21-6


    Just using GFS there as example of why BB is wrong with automatic assumptions about Dew Points in the Irish Sea. Of course it is very possible we could end up the wrong side of marginal - but equally possible things will favour snow even more.


  • Registered Users Posts: 16,533 ✭✭✭✭nacho libre


    Evelyn has it on the cold side all week. still it wouldn't surprise me if in fact the fronts come further north than anticipated and it gets relatively milder.. though i think it's safe to say we won't see double figures anytime soon.

    anyway glad to see some of the people who were snow starved got to see some sneachta last night.


  • Closed Accounts Posts: 4,279 ✭✭✭Su Campu


    darkman2 wrote: »
    No, she did not mention, "away from the coasts" - even if she did I don't particularly need to pay attention to what she says anyway considering the charts are right in front of us.

    That's a bit of an arrogant statement, don't you think?




  • Darkman2.. in january 1982,temperatures in Britain especially most of wales off which we were getting a fast gale force surface feed were sub zero.

    We don't have that this week.
    It's a crucial difference.
    What we do have is a circulation that runs up through rain in southern Britain,runs through snow in colder central Britain and then gets remodified whilst crossing the irish sea.

    Eveylyn did mention away from coasts and she's said that to be realistic.

    Heres the air temps over Britain today before the irish sea gets to work on them

    http://www.wunderground.com/cgi-bin/findweather/getForecast?query=united%20kingdom&wuSelect=WEATHER

    Cardiff is 7c which is a hell of a difference from the daytime surface feed of january 1982.

    Like should be compared with like.


  • Registered Users Posts: 2,876 ✭✭✭JanuarySnowstor


    Su Campu wrote: »
    That's a bit of an arrogant statement, don't you think?

    I didn't hear her say "away from coasts" and if she did she was clearly talking about Southern areas. Met Eireann have been proved wrong time and time again and the likes of us have been right so why shouldn't he and we be arrogant!

    I think BB has a fair assesment but who knows, certainly not Met Eireann imo


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    Su Campu wrote: »
    That's a bit of an arrogant statement, don't you think?

    Not at all. She is using the exact same charts as us. Certain people on here, at this stage, should be well capable of making forecasts without having to go near the media at all. It actually makes me laugh when people say "the Eagle" said this....."Evelyn" said that.....as if it means something. It means nothing because if you can read the charts - they are right there in front of you and it is very easy to come to your own conclusions often in far more detail then any media broadcast.


  • Registered Users Posts: 2,876 ✭✭✭JanuarySnowstor


    Darkman2.. in january 1982,temperatures in .

    Heres the air temps over Britain today before the irish sea gets to work on them

    http://www.wunderground.com/cgi-bin/findweather/getForecast?query=united%20kingdom&wuSelect=WEATHER

    Cardiff is 7c which is a hell of a difference from the daytime surface feed of january 1982.

    Like should be compared with like.

    In all fairness that temp has been taken in likely sunny conditions, middle of the day. With heavy ppn they would likely be 1-2C
    I agree it looks very marginal throughout the week, but darkman's has a point in that there is potential for snow. I think somewhere between both your views lies the truth!


  • Banned (with Prison Access) Posts: 8,633 ✭✭✭darkman2


    Darkman2.. in january 1982,temperatures in Britain especially most of wales off which we were getting a fast gale force surface feed were sub zero.

    We don't have that this week.
    It's a crucial difference.
    What we do have is a circulation that runs up through rain in southern Britain,runs through snow in colder central Britain and then gets remodified whilst crossing the irish sea.

    Eveylyn did mention away from coasts and she's said that to be realistic.

    Heres the air temps over Britain today before the irish sea gets to work on them

    http://www.wunderground.com/cgi-bin/findweather/getForecast?query=united%20kingdom&wuSelect=WEATHER

    Cardiff is 7c which is a hell of a difference from the daytime surface feed of january 1982.

    Like should be compared with like.

    It's much more complex then what your making out. I will tell you what. The simplist way to know is to wait till Tuesday and we will see who is right and who is wrong. If, things don't change radically, and we end up with an Easterly or Northeasterly and rain then I will gladly admit to being wrong.


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  • Registered Users Posts: 2,876 ✭✭✭JanuarySnowstor


    darkman2 wrote: »
    Not at all. She is using the exact same charts as us. Certain people on here, at this stage, should be well capable of making forecasts without having to go near the media at all. It actually makes me laugh when people say "the Eagle" said this....."Evelyn" said that.....as if it means something. It means nothing because if you can read the charts - they are right there in front of you and it is very easy to come to your own conclusions often in far more detail then any media broadcast.
    I rarely watch the weather now since we have access to the charts.
    They are nearly always working on old models, though I do find the beeb very accurate and got last nights ppn and timing frightenly accurate!!


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