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Cold Spell - Snow & Ice Possible Thursday 8th / Friday 9th

  • 01-02-2018 10:09pm
    #1
    Registered Users Posts: 21,811 ✭✭✭✭ Kermit.de.frog


    Discussion thread for potential bitterly cold weather from Sunday evening.

    Potential hazards:
    • Ice,
    • Frost,
    • Snow,
    • Cold Temperatures

    We can only really go to Monday night with much confidence in the smaller details however it will be a much colder week overall, there is no doubt about that.

    Daytime maxima temperatures from Monday - Friday 0 - 5 c.

    Minima Monday - Friday +1 - -7 c (coldest midweek)


    The first real snowfall risk is from Monday evening nationwide as a frontal system tries to come in from the Atlantic. It will meet exceptionally cold air over Ireland and to our east - and - be followed closely by exceptionally cold air to our west.

    As the cold air to the west "catches up" and mixes with that to the east the front stalls, occludes and has no further desire to live (:() except go out in a blaze of glory and apocalyptic snow bomb :pac:


    Well, not quite...

    To illustrate on Monday afternoon (you see here the two cold air masses meeting over Ireland) :

    UW96-7.GIF?01-18

    There are plenty of charts that have been posted in the model discussion thread here.

    https://www.boards.ie/vbulletin/showthread.php?t=2057782713&page=53

    The front will stall and weaken but should give some snowfall before dieing out as it heads in to the Irish sea. This could be disruptive for Tuesday morning. Amounts too tricky to call at this stage - if I had to take a punt i'd go with 2 - 5 cm's to low levels for now.

    Could yet be more but the midlands and east are most at risk.

    There are still some differences between the models on Monday - some offer more extensive snowfall and colder temperatures than others.

    *Night time temperatures will be very cold and well below freezing extensively - severe frost and ice and where snow lies temperatures will be even lower again.

    We'll keep an eye on the rest of the week.

    Sneak peek for Tuesday.

    EDM0-120.GIF?01-0

    To recap bitterly cold from Sunday evening and for the rest of next week. Extensive frost and ice, snowfall at times, some disruption possible.

    Exciting eh?:)

    P.S If anyone would like to recommend a structure for these threads please do. It's a lot of information to try to get in to the OP to try and keep as simple as possible for you without doing a thesis:o


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Comments

  • Moderators, Science, Health & Environment Moderators Posts: 10,462 Mod ✭✭✭✭ Meteorite58


    From what I am seeing in the models atm is a slow moving cold front passing over the country ( W to E ) on Monday into Tues morning which is moving in to cold air and cold air following it. Looks very cold overnight Sun night into Mon morning and Temps getting up around 4 or 6C the first half of the day and dropping in the afternoon towards evening to perhaps 0 to 3C. The front looks to produce snow albeit wet perhaps with sleet and rain at stages. How much will it snow, where and will it stick all to be determined closer to the day. Would imagine that high ground at least will get a good coating. What I will be watching is for an increase in cold uppers, increase in an Easterly breeze to see if it slows down the front or will it stall. Tues looks like a very cold day so any accumulated snow on high ground could be slow to melt.

    Tues a good day for Satellite Pictures of snow cover perhaps.

    Tues wintry showers and Tues night/ Weds morning Streamers on the Irish sea perhaps moving onto the E coast.


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  • Registered Users Posts: 14,307 ✭✭✭✭ nacho libre


    I'm not so sure this will be a classic winter snow fall of time gone by- to be fair no one is saying it will be. What i mean is to 3- 5 cm of snow is no great shakes. A classic snow fall is one where we get between 10 - 20 cm on lower ground. We've really not had one like that since the 80's. I would love if we all got to experience something like that. It would go down in snow lore:)


  • Closed Accounts Posts: 248 ✭✭ kod87


    My main concern is the amount of precipitation, current models not showing particularly heavy and if you consider it will be wet sleet/ snow at lower levels, then it will not amount to much at lower levels. As usual, high ground is the place to be.


    Frontal snow rarely delivers much in terms of snow depth in this country, unless the front happens to stall right over us and maintains intensity, we need a lot of stars to align for that to happen.


  • Registered Users Posts: 1,894 ✭✭✭ BLIZZARD7


    I'm not so sure this will be a classic winter snow fall of time gone by- to be fair no one is saying it will be. What i mean is to 3- 5 cm of snow is no great shakes. A classic snow fall is one where we get between 10 - 20 cm on lower ground. We've really not had one like that since the 80's. I would love if we all got to experience something like that. It would go down in snow lore:)

    Get the cold in first and the snow will follow, if all goes as forecast so far I'd be surprised if the potential for such a snowfall doesnt arise at some point soon. Maybe it will be mainly cold and dry but snow depths are definitely still open to change and therefore improvement ;)


  • Registered Users Posts: 14,307 ✭✭✭✭ nacho libre


    kod87 wrote: »
    My main concern is the amount of precipitation, current models not showing particularly heavy and if you consider it will be wet sleet/ snow at lower levels, then it will not amount to much at lower levels. As usual, high ground is the place to be.


    Frontal snow rarely delivers much in terms of snow depth in this country, unless the front happens to stall right over us and maintains intensity, we need a lot of stars to align for that to happen.

    Yes, that's my point they are rare, but sometimes the stars do align-we are overdue this happening. We did get 10 cm from a frontal event in December but that was localised and gone after two days. Blizzard does make a good point, if we sustain the cold, the chances of a second or third frontal event producing an epic widespread snowfall to lower level increases.

    Come on snow you can do it:)


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  • Closed Accounts Posts: 248 ✭✭ kod87


    Yes, that's my point they are rare, but sometimes the stars do align-we are overdue this happening. We did get 10 cm from a frontal event in December but that was localised and gone after two days. Blizzard does make a good point, if we sustain the cold, the chances of a second or third frontal event producing an epic widespread snowfall to lower level increases.

    Come on snow you can do it:)

    Well, we all hope so :)


  • Registered Users Posts: 2,728 ✭✭✭ Rebelbrowser


    ECM still good this morning to my untrained eye. -6 or less uppers from Monday evening basically right through to the end of the run......


  • Registered Users Posts: 767 ✭✭✭ Snowbiee21


    I can’t see why there’s just much pessimism, ecm is still pretty much the same as yesterday


  • Registered Users Posts: 119 ✭✭ King of Spades


    Looking to get some work done outside the house from Monday. Was hoping it’ll be dry or mostly dry for a few days. What do ye think? I’m in central Meath. Thanks!


  • Registered Users Posts: 3,993 ✭✭✭ giveitholly


    Not a bad forecast by Joanne donnelly there now,mentions the potential for Monday night


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  • Registered Users Posts: 17,665 ✭✭✭✭ JCX BXC


    Looking to get some work done outside the house from Monday. Was hoping it’ll be dry or mostly dry for a few days. What do ye think? I’m in central Meath. Thanks!

    www.met.ie

    https://touch.boards.ie/thread/2055579971/395


  • Registered Users Posts: 119 ✭✭ King of Spades


    Thanks JCX. It’s just that from reading these threads before, ye lads seem to get things right in the outlook more than Met Eireann!


  • Closed Accounts Posts: 2,043 George Sunsnow


    It’s easy to see where the front is on Tuesday!
    A squeeze of very cold air from both sides
    There’s better outcomes if air from the east wins
    I think snow to sea level in lots of places is a greater than 70% chance in that air flow assuming we advect enough of the surface cold from the east into the mix if you follow?
    It’s quite a forecast challenge because even though the uppers are -4c,it’s still warmer air meeting colder so for a time you are going to get heavier precipitation before the engagement with that dryer colder air as the front enters Britain weakens it
    If conditions are right for snow under the heavier precip,you’ll know all about it

    3e7c000033ec4bbe2bfc4d1cf3c64ed1.jpg


  • Closed Accounts Posts: 1,576 patneve2


    Going by the ECM an inch or two is definitely possible in many low lying areas and even on the E coast late Monday/ early Tuesday. Hopefully the next few runs will confirm this potential.


  • Registered Users Posts: 19,207 ✭✭✭✭ Larbre34


    Thanks JCX. It’s just that from reading these threads before, ye lads seem to get things right in the outlook more than Met Eireann!

    To be fair, a range of outlooks are covered here due to all the models being considered and the debate is around the reliability of each. No more than with Met E those forecasts can change significantly as the models resolve.

    If an atlantic front is coming, its fairly safe to say it will be rain within X window of time, because the range of parameters for it to rain and be breezy are so wide. For something like a cold airmass arriving and snow potential, in the Irish context we need a lot of parameters to go our way, hence the fingernail chewing that goes on here. My rule of thumb is that if wintry falls are in the outlook, I dont make any plan of action around anything Im doing until +36 hours away from the event. Its just not reliable enough until then.

    That said, whether there are showers or not, the dry spells for you to get your work done are fairly nailed on to be very cold with added windchill.


  • Registered Users Posts: 119 ✭✭ King of Spades


    Larbre34 wrote: »
    To be fair, a range of outlooks are covered here due to all the models being considered and the debate is around the reliability of each. No more than with Met E those forecasts can change significantly as the models resolve.

    If an atlantic front is coming, its fairly safe to say it will be rain within X window of time, because the range of parameters for it to rain and be breezy are so wide. For something like a cold airmass arriving and snow potential, in the Irish context we need a lot of parameters to go our way, hence the fingernail chewing that goes on here. My rule of thumb is that if wintry falls are in the outlook, I dont make any plan of action around anything Im doing until +36 hours away from the event. Its just not reliable enough until then.

    That said, whether there are showers or not, the dry spells for you to get your work done are fairly nailed on to be very cold with added windchill.

    Thanks Larbre. Very helpful. Will get the gloves, hat and scarf ready anyway!


  • Registered Users Posts: 21,811 ✭✭✭✭ Kermit.de.frog


    Slight upgrade for Monday across the models this morning. GFS has the -8 850 hpa isotherm reaching eastern extremities ahead of the arrival of that weather front. A couple of degrees colder than previous.

    gfs-1-78.png?6

    ECM/UKMO both are colder over the country again but the GFS is trending toward them and slowly increasing the snow threat Monday night.

    Also GFS just toying with longer snowy precipitation through Tuesday night - that could be the next situation to watch


    I'll be back with more after the 12 pm model output.

    Lovely sunshine today - enjoy! :)


  • Registered Users Posts: 5,951 ✭✭✭ munsterlegend


    Usually the GFS is producing the colder and snowier charts but seems to be the ECM this time. I am not expecting anything here in cork except maybe higher ground as these frontal events have a tendency to go pearshaped but further east looks promising depending how far the block shifts west.

    It will be an interesting week ahead.


  • Registered Users Posts: 1,591 gabeeg


    What models are people favouring for this?

    The UKMO was the first to pick up on it, AFAIK, and is still predicting a very cold outcome.


  • Registered Users Posts: 1,773 ✭✭✭ dacogawa


    Met Eireann are starting to go for it a bit now too, be interesting to see their next update later this afternoon, Monday night/Tuesday morning does look very interesting now and within the reliable 96 hour time frame (is 96 hours reliable for snow, more like 96 minutes :D )

    If the ECM is right and we do get snowfall at lower levels on Monday/Tuesday I can see the "persistent spell of rain later in the week" in the forecast below being very interesting... if, if, if though :rolleyes:

    Met.ie (outlook)

    Sunday night will continue mainly dry, and under clear skies with light winds, temperatures will fall to between -2 and zero degrees. There will be a widespread sharp frost.

    Monday will start out cold and frosty with light southeast winds veering southerly during the day. It will be a dry day with sunny spells and temperatures will be 3 or 4 degrees at most in the east during the day time, and only 4 or 5 degrees at most in the west.

    On Monday night southwest winds will veer northwesterly as a frontal trough passes over the country. This weather front is expected to bring a rain and snow mix, with accumulations possible to lower levels by morning as temperatures fall below freezing once again.

    A cold day for Tuesday. Most of the country will be dry with sunny spells, but along the west and north coasts there will be showers, these likely to be of sleet and snow at times, later in the day there is a risk of showers along the east coast too.

    The further outlook to midweek is for a continued cold spell with temperatures well below freezing at night. Winds will be mainly light to moderate northwesterly and showers will mostly affect coasts, with a more persistent spell of rain later in the week.

    ECM0-144.GIF?02-12


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  • Closed Accounts Posts: 40,086 ✭✭✭✭ Harry Palmr


    More over-excitement on this forum I suspect. Cold, windy with some sleet and snow.

    MOD Note : Warning Given you know well the type of reaction your post will get


  • Closed Accounts Posts: 3,502 Jordy Immense Malaria


    More over-excitement on this forum I suspect. Cold, windy with some sleet and snow.

    Not enough excitement if you ask me, cold, windy, 2 feet of snow.


  • Registered Users Posts: 19,207 ✭✭✭✭ Larbre34


    Not enough excitement if you ask me, cold, windy, 2 feet of snow.

    Come off it, some people actually come on here looking for serious guidance.


  • Closed Accounts Posts: 248 ✭✭ kod87


    More over-excitement on this forum I suspect. Cold, windy with some sleet and snow.

    Actually, people on here seem to be pretty relaxed and grounded by this one, it's kinda nice and refreshing not going OTT with expectation.


  • Closed Accounts Posts: 3,502 Jordy Immense Malaria


    Larbre34 wrote: »
    Come off it, some people actually come on here looking for serious guidance.

    Well then there's no point in saying there is over excitement, if people come on here and only see rain and sleet yet there's a dumping of snow, you'd be in a worse situation.


  • Registered Users Posts: 14,307 ✭✭✭✭ nacho libre


    dacogawa wrote: »
    .The further outlook to midweek is for a continued cold spell with temperatures well below freezing at night. Winds will be mainly light to moderate northwesterly and showers will mostly affect coasts, with a more persistent spell of rain later in the week.
    ECM0-144.GIF?02-12

    That does seem to be deliberately vague about the spell of rain later in the week. Is it a spell of persistent rain for all, or just costal fringes? I have a feeling if cold air is entrenched that might be changed to something more promising in future up dates.


  • Moderators, Technology & Internet Moderators Posts: 17,098 Mod ✭✭✭✭ cherryghost


    The next 7 days looks pretty exciting in general. Monday into Tuesday is only phase 2 of possible multiple fronts passing over us


  • Registered Users Posts: 2,728 ✭✭✭ Rebelbrowser


    Yeah, just your common or garden westerlies with -10 and -11 uppers over us in 3 and half days time.....

    18020606_0212.gif


  • Registered Users Posts: 6,447 ✭✭✭ pad199207


    Is the GFS looking a bit drab on the 12z?


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  • Moderators, Science, Health & Environment Moderators Posts: 7,132 Mod ✭✭✭✭ pistolpetes11


    pad199207 wrote: »
    Is the GFS looking a bit drab on the 12z?

    Is It :pac::pac::pac::pac::pac:

    440496.png


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