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Snow watch until Sunday 24th (N,W,SW most at risk)

  • 18-01-2021 5:06am
    #1
    Registered Users Posts: 21,795 ✭✭✭✭ Kermit.de.frog


    Thread for flooding potential Connaught, North Leinster, South Ulster through Monday night/Tuesday/first half of Wednesday.

    Heavy snow potential second half of Wednesday particularly Leinster and Munster. Much colder by evening.

    Surprised a thread wasn't started for the flood potential. Will update this OP in the morning.

    Interesting 48 hours to come from tonight to say the least.


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Comments

  • Registered Users Posts: 11,836 ✭✭✭✭ Rock Lesnar


    Flooding, great


  • Registered Users Posts: 2,816 ✭✭✭ redsteveireland


    ...

    Surprised a thread wasn't started for the flood potential. Will update this OP in the morning.

    Interesting 48 hours to come from tonight to say the least.

    All too pre-occupied with the Snow-casting!


  • Registered Users Posts: 8,192 ✭✭✭ Gaoth Laidir


    Can't see any real snow potential with this at all, apart from mountains. There's just no cold out to our north. Sounding from as far north as Iceland and Jan Mayen, from where Wednesday's northerly will come, just don't give much hope.

    https://meteologix.com/ie/radiosonde-values/83-w-662-n/temperature/20210118-0000z.html


  • Registered Users Posts: 5,830 ✭✭✭ TheMilkyPirate


    6z showing a 6-7 hour window for snow for the southeast. Can't imagine it will amount to much but interesting all the same.

    54-574UK.gif

    57-574UK.gif

    60-574UK.gif


  • Posts: 0 ✭✭✭ [Deleted User]


    Can't see any real snow potential with this at all, apart from mountains. There's just no cold out to our north. Sounding from as far north as Iceland and Jan Mayen, from where Wednesday's northerly will come, just don't give much hope.

    https://meteologix.com/ie/radiosonde-values/83-w-662-n/temperature/20210118-0000z.html

    Bbc 24 forecast for what it's worth has it turning to snow in kildare wenesday afternoon which would be meteogroup's opinion
    They're blending a few models presumably


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  • Registered Users Posts: 447 ✭✭ KingdomRushed


    The 6Z GFS (parallel) has much more prolonged snowfall modelled for wednesday for much of eastern Ireland than the actual GFS run for same period. How do people rate that model in the short term


  • Registered Users Posts: 955 ✭✭✭ esposito


    The 6Z GFS (parallel) has much more prolonged snowfall modelled for wednesday for much of eastern Ireland than the actual GFS run for same period. How do people rate that model in the short term

    Very good question kingdom. Don’t you just wish there was one GFS model to ease the tension/uncertainty.

    Isn’t the parallel supposed to replace the old GFS very soon. If it is then surely it has to be taken seriously?


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


    esposito wrote: »
    Very good question kingdom. Don’t you just wish there was one GFS model to ease the tension/uncertainty.

    Isn’t the parallel supposed to replace the old GFS very soon. If it is then surely it has to be taken seriously?

    I've read of late it's second only to the ECM out to day 5, but is quite poor beyond that.


  • Registered Users Posts: 1,967 ✭✭✭ blindsider


    AuntySnow wrote: »
    Bbc 24 forecast for what it's worth has it turning to snow in kildare wenesday afternoon which would be meteogroup's opinion
    They're blending a few models presumably

    https://en.wikipedia.org/wiki/BBC_Weather

    BBC WEather supplied by Meteogroup since 2018....I missed that :o


  • Registered Users Posts: 8,369 ✭✭✭ Danno


    GFSPARAUK06_54_53.png

    This is the GFS PARA at 54hrs. Shows 5hrs of moderate to heavy snow for inland Munster and South and Central Leinster but those along the immediate east coast may not get as much until a couple of hours later (well into the afternoon) but hangs around the east coast counties for a good few hours well into night.


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  • Registered Users Posts: 8,369 ✭✭✭ Danno


    GFSPARAUK06_61_25.png

    Again the GFS PARA here - this time at 7pm Wednesday evening showing good accumulations across the east and south midlands, up to 11cm on the western side of the Wicklow Mtns! Pad will be happy! :)


  • Registered Users Posts: 8,369 ✭✭✭ Danno


    The GFS PARA model is playing this out quite similar to the December 2017 event, however seems to be more snow getting into the east and southwest with this.


  • Registered Users Posts: 12,554 ✭✭✭✭ sryanbruen


    U.K. Met Office have named this as Storm Christoph.

    Weather and climate site - https://www.ukandirelandclimate.com/ (advised to view on PC, not optimised for mobile)

    Photography site - https://www.sryanbruenphoto.com/



  • Posts: 0 ✭✭✭ [Deleted User]


    Danno wrote: »
    The GFS PARA model is playing this out quite similar to the December 2017 event, however seems to be more snow getting into the east and southwest with this.

    Naas had rain in that
    Tullow Co carlow had rain but carlow town had several cases of snow just a few kms further inland
    As the then snow band slid southeast, snow fell at sea level on the coast in waterford, the cold air travelling with and staying in position inside the front
    The part which had already turned to snow sliding into waterford whereas further up the east coast the marine and rain influence remained
    Here in Arklow and near the Irish sea the snow line was 400 metres and stayed that way in marine influence that pushed in to cover much of kildare


  • Registered Users Posts: 21,795 ✭✭✭✭ Kermit.de.frog


    For snow potential there is uncertainty as to how far north rain bands get through Wednesday. Quite a mix of outcomes. I'll wait until later to see if it's more conclusive. The further north the greater the chance of snow.

    In relation to flooding I see ME going for up to 50mm in some places. I'd go along with that. Could be a little more locally. Rain kicks off this evening in all areas but focus is north Midlands, North Leinster, South Ulster and North Connaught for flood potential.


  • Posts: 0 ✭✭✭ [Deleted User]


    Just to add,the difference between this event is in the South east this time wind is off the land not the sea
    Huge difference especially to the east of high ground if snow is going to fall to sea level
    The cold air digging will also have had a long land track over the island to South leinster especially neutralising a lot of its marine wateryness
    More guidance tomorrow and probably even Wednesday needed to call this


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


    It looks more wet than white for alot of us, unless there is a big change. Hopefully it does not start trending more south to the point that everyone misses out.


  • Registered Users Posts: 1,889 ✭✭✭ John.Icy


    My part of S.Kildare (near the Carlow/Laois border) had a great time of Dec 2017, lots of snow. You could throw a sheet over the regions of S.Kildare, East Laois and parts of N.Carlow that did really well out of the event in terms of majority snow (away from high ground), rather than waiting for a transition or back edge action only.

    There was also a frontal event on the 13 Nov 2019 that this same zone saw heavy snow while many others just saw rain. Maybe a few other regions too but we seem to have a fair few posters in this area and I don't remember seeing many places with as much snow as Athy, Port Laoise, Monasterevin etc. and other towns within the similar region.

    EDIT: If onshore winds aren't that much of a factor the above may all be irrelevant.


  • Registered Users Posts: 12,653 ✭✭✭✭ ninebeanrows


    It is all relying on evaporative cooling to enhance the cold undercut.

    Just checking this morning's runs and the risk is reduced as the occlusion is set to slide somewhat further east than some runs yesterday.

    If low develops a bit quicker it will increase the chance of the occlusion trailing over the east and southeast for sometime..

    It is very much a marginal event that requires reasonably intense precipitation, profile aloft should be sufficient for snow if lower layer can be cooled by the precip intensity, but this morning's output seem to lessen the risk of intense precip and clear the system quicker

    Arpege usually give a good idea of where wintry precip is most likely.

    Places like Carlow and Wicklow seem favoured at the minute

    arpegeuk-1-54-0.png?18-12


  • Registered Users Posts: 8,192 ✭✭✭ Gaoth Laidir


    Current snow lines (m amsl), from the 12Z radiosondes. Not great up north. On Wednesday we'd be relying on some fairly substantial uplift or surface cooling to turn things to snow down the midlands. Evaporative cooling should not be possible as the lowest layers will be already saturated.

    539882.png


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  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    It's going to be a wet couple of days, but the ECM 6Z isn't having any snow other than in high lying areas:

    qcYZ0LT.gif


  • Registered Users Posts: 21,795 ✭✭✭✭ Kermit.de.frog


    Oh I dunno. Seems to be a dose of healthy scepticism that may yet turn out to be unhealthy in the end. If we look at the GFS (upcoming) this is exactly what we want to see. The snow level falling all the time. This is just one of a variety of outcomes but it's an example of what could well occur.

    anim_abd9.gif

    anim_gfk1.gif

    anim_ulf7.gif

    anim_ktv5.gif

    The 6z ECM is actually a bit of an upgrade in terms of potential - just need a little bit more evolution from there. A tad more northwest and boom!

    I wouldn't be calling things either way. I think we have a good chance here but it depends ultimately on the location and orientation of those frontal zones. Long story short the further north the better and that's what i'll be looking for.


  • Moderators, Science, Health & Environment Moderators Posts: 15,171 Mod ✭✭✭✭ Gonzo


    hopefully this proves further north and further west but at the moment i'm not expecting much if anything here in Meath unless there is an upgrade with the positioning. This could easily miss the entire country as well.


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


    Gonzo wrote: »
    hopefully this proves further north and further west but at the moment i'm not expecting much if anything here in Meath unless there is an upgrade with the positioning. This could easily miss the entire country as well.

    All I'll get is accumulations of rain. It's fantastic if you love rain , i suppose. Anyway good to see a forum tradition is being maintained this thread


  • Moderators, Science, Health & Environment Moderators Posts: 15,171 Mod ✭✭✭✭ Gonzo


    All I'll get is accumulations of rain. It's fantastic if you love rain , i suppose. Anyway good to see a forum tradition is being maintained this thread

    no shortage of rain over the next 10 days either. A very wet 3 days to come, then dryer and next week is already starting to look like plenty of regular rain. January will definitely exceed 100mm in places by the end of the month.

    240-777UK.GIF?18-6


  • Registered Users Posts: 718 ✭✭✭ Kunta Kinte


    Gonzo wrote: »
    no shortage of rain over the next 10 days either. A very wet 3 days to come, then dryer and next week is already starting to look like plenty of regular rain. January will definitely exceed 100mm in places by the end of the month.

    240-777UK.GIF?18-6

    And what about February? More of the same then?


  • Registered Users Posts: 8,192 ✭✭✭ Gaoth Laidir


    Oh I dunno. Seems to be a dose of healthy scepticism that may yet turn out to be unhealthy in the end. If we look at the GFS (upcoming) this is exactly what we want to see. The snow level falling all the time. This is just one of a variety of outcomes but it's an example of what could well occur.

    The 6z ECM is actually a bit of an upgrade in terms of potential - just need a little bit more evolution from there. A tad more northwest and boom!

    I wouldn't be calling things either way. I think we have a good chance here but it depends ultimately on the location and orientation of those frontal zones. Long story short the further north the better and that's what i'll be looking for.

    Nothing showing in those charts imo. Still a sloppy mix at best. I'm not seeing any difference in the 06Z ECM, and all other higher-res models in agreement. The showery troughs following on later on Thursday may have some more wintry intensity-based snow but the overall airmass is just a regurgitating Atlantic slop-fest, unless something drastic changes.


  • Registered Users Posts: 12,653 ✭✭✭✭ ninebeanrows


    Local HIRES model ensembles say yes to snowcover in many parts of Leinster by Wednesday evening.

    Long way to go though and will be sloppy for most


  • Registered Users Posts: 14,539 ✭✭✭✭ Supercell


    The T+60 fax has the occlusion well south of us by midday, with a slack cool airflow, I really dont see anything but rain bar the usual high places in Wicklow mainly.

    539893.jpg

    Have a weather station?, why not join the Ireland Weather Network - http://irelandweather.eu/



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  • Posts: 0 ✭✭✭ [Deleted User]


    Supercell wrote: »
    The T+60 fax has the occlusion well south of us by midday, with a slack cool airflow, I really dont see anything but rain bar the usual high places in Wicklow mainly.

    539893.jpg

    Those fax charts seem to change every issue
    The 528 dam on the last one they did covered all of Ireland bar cork and kerry
    There it avoids the whole country
    Rain glorious rain
    There'll be another different one tomorrow


This discussion has been closed.
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