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[25 Oct-5 Nov] mild, sometimes windy and wet, weather with potential for disruptive rainfalls

  • 25-10-2022 5:49am
    #1
    Registered Users Posts: 14,235 ✭✭✭✭


    There are going to be a number of marginal warning situations in coming days when strong Atlantic fronts arrive, both for wind speeds and rainfall amounts. It's more a case of an accumulating total rainfall that concerns me at present, with each system adding a new total of 15-25 mm. The latest GFS guidance changes in one regard, it has been featuring high totals along the south coast over 10-14 day periods, but now shows these pushing into the bulk of central Ireland in about a week's time (meaning that signals have emerged for stronger lows next week from a southerly source region). This thread can track the various events which begin with some strong winds and briefly heavy rainfalls tonight and Wednesday (northwest coasts could see gusts around 110 km/hr). A more widespread and active frontal passage is set for Thursday night into Friday morning and could be quite strong for the east coast as a strong southerly gradient develops. After that, it's a case of monitoring the ever-changing details on a parade of further lows that seem to be lining up for as long as the upper level flow will tolerate them, at the moment there are no strong signals of this ending and one system in particular that may evolve into something different, but timed for early next week (into the first or second of November time frame).

    The current GFS output shows central Ireland at 120 mm total rainfall within 8-9 days, but about half of that seems to be reserved for a system towards days 7-9 so this could change. It is a new signal compared to previous runs. As I mention in the forecast discussion, rather high sea surface temperatures over the Biscay region following the hot summer of 2022 could feed energy and moisture into any lows that form down that way and which then move north towards Ireland. But before this potential heavy rainfall we have about three active systems coming along in more of a southwesterly flow that will, if not producing flood potential directly, set the stage for any later heavy rain to become problematic. This is the peak rainfall portion of the year, and I think it was Nov 2009 when that potential was most realized across parts of Ireland and northwest Britain.



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Comments

  • Registered Users Posts: 6,804 ✭✭✭pauldry


    Yes indeed MT. November 2009 we had 279mm of rain in Sligo. Leitrim had over 300mm and Carrick was flooded for the whole month. Wev had 122mm in October and Markree is over 150mm so if your prediction is right we will pass 200mm. I think February a couple of years ago, 2020 we got 240mm up here. That was the wettest I remember in past few years. This Southerly source of rain is a disaster as it keeps feeding pulses of heavy rain and with all the leaves it promotes flooding.



  • Moderators, Science, Health & Environment Moderators Posts: 16,631 Mod ✭✭✭✭Gonzo


    I don't think I have ever seen a GFS 10 day precipitation chart as wet as this mornings one for overall coverage of 100mm+ of rainfall.

    Flooding and disruption is bound to happen over the next 10 to 14 day period. There is also the possibilities of more thunderstorm potential next week.



  • Registered Users Posts: 5,384 ✭✭✭giveitholly


    Recorded over 185mm of rainfall here in tipp in September and already up to 175mm for October



  • Moderators, Science, Health & Environment Moderators Posts: 16,631 Mod ✭✭✭✭Gonzo


    GFS 6z is even more over the top with rainfall, predicting up to 175mm of rainfall for some western areas over the next 10 days.

    November is looking increasingly unsettled well into the month, could we be on track for a re-run of the November 2009 floods?



  • Registered Users Posts: 28,573 ✭✭✭✭Wanderer78


    shite, and i wanted to go camping next week!



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  • Registered Users Posts: 6,804 ✭✭✭pauldry


    Probably another 100mm in most places the next 2 weeks. Some dry spells in between the heavy rains too so it might feel OK at times.

    Coastal stations of the West and South could get over 150mm more

    By the by Gonzo where do I get those charts for Accum Precip?



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    My house is kind of perched on a raised concrete base... Where that ends a moat develops between concrete path and gate. I learned why my first winter here and am deeply appreciative..

    West Mayo offshore



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


    Getting fed up of this rain now - Luckily the mid-month of September was dry. Think five or six weeks of this is enough for any soul to bare.



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    There is nothing optional unfortunately.



  • Registered Users Posts: 177 ✭✭odyboody


    Hmm, Its what followed the floods I'd be waiting for.



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  • Registered Users Posts: 7,072 ✭✭✭pad199207




  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    That does it. Hibernation definitely calls...



  • Moderators, Science, Health & Environment Moderators Posts: 16,631 Mod ✭✭✭✭Gonzo


    Visit the Meteociel website https://www.meteociel.fr/modeles/gfs/royaume-uni/precipitations/3h.htm

    click GFS with the UK flag and then in the options click the Accu. precipitations thumbnail and that will show you the precipitation totals over 10 days for Ireland and the UK.



  • Registered Users Posts: 8,193 ✭✭✭Cluedo Monopoly


    The Shannon is rising.

    Athlone station.

    Realtime waterlevel

    What are they doing in the Hyacinth House?



  • Registered Users Posts: 14,235 ✭✭✭✭M.T. Cranium


    The 12z and 18z GFS output is a little less dramatic for total rainfall potential, but this could go in cycles for a few days. The reason for the downgrade (if 70-90 mm can be called that) is no particularly strong low to follow around 1-2 Nov from a southerly direction. It could return to the picture though.

    One wave of rainfall has pretty much come and gone in the past six hours, with some downpours in various locations. A stronger south wind will develop overnight and it could get briefly rather blustery on the Mayo coast around 0300-0600h. That will relent gradually during the morning and the next wind maximum looks like being mostly for the southeast coastal areas around midnight to 0300h Friday early morning, with a sharply defined front heading for Britain, could produce a broken squall line feature for south central and eastern counties during the night (Thursday night into Friday morning).

    Nothing too dramatic shown for following days but the 12z GFS prolonged the mild signal and had some fairly energetic looking systems as far out as 8-10 November.



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    Just normal autumn weather! We had such a lovely spell....



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    And it has morphed into a loud, violent morning. Everything that can be moved outside has been ...relocated.

    And it gets worser and worser and some of the guttering is loose now. Shaking and rattling...

    Hard heavy rain.

    Welcome autumn!

    West Mayo offshore

    Post edited by Graces7 on


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 17,534 Mod ✭✭✭✭DOCARCH


    A heap of rain overnight in Greystones. 37.4mm since yesterday afternoon.



  • Registered Users Posts: 10,010 ✭✭✭✭Oscar Bravo


    A gust of 61 knots(113km/h) at Mace Head on the 7am met reports. Stormy along the Galway/Mayo coast



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    Indeed it is. Stormy.. Tempestuous. Sudden bellows of gale sound... ... Hoping the power holds ..It is the gusts that tend to do the damage

    West Mayo offshore



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  • Registered Users Posts: 14,235 ✭✭✭✭M.T. Cranium


    So after its pause the GFS model has returned to a very stormy outlook 1-2 Nov, which would return the total rainfall to the more extreme values as well as providing risk of locally very strong winds. Track is from SSW to NNE through the midlands. European model has the development a bit later (more like 2-3 Nov) and approaching from southwest. GEM has not detected anything intense but shows the larger scale pattern (this would not be the first time GEM took its time catching up).

    Usually if you have cross-model convergence on a solution by day five in these situations, you've got an actual storm and not a model fantasy session, the timing fits my research model also. Already two or three jogs in the road to the actual outcome but to give some idea how gradually models have been responding to this stormy signal, there were charts a week ago showing cold northeast flow and sleet potential in early November. The strength and duration of this mild spell were poorly handled in the longer range charts available mid-month. So the trend is towards more development, of course that could over-correct at some point.



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    It is always hard to assess the first storms.- from a layperson;s viewpoint - after a period of such deep calm as we have just enjoyed.

    Initial assessment from a simple resident. is of considerable ferocity. A day to take great care. ie stay inside when living so near the ocean. Just a field away at the back here.

    A steady strong wind is less potent and damaging than this fiercely gusting gale. I learned in my first winter here to respect utterly this phenomenon. I opened the door as a gust hit and was literally flung bodily across the concrete path almost to the stone wall.

    Now the door is safe;y anchored so it cannot swing out like that.

    Please take great care out there.



  • Registered Users Posts: 672 ✭✭✭cheezums


    Early morning Friday looking pretty wild.



  • Registered Users Posts: 32,634 ✭✭✭✭Graces7


    easing a little for now. Bright sun! What St Patrick ( The Lorican) referred to as " The whirling wind's tempestuous shocks" have eased somewhat. For now...

    Post edited by Graces7 on


  • Registered Users Posts: 2,866 ✭✭✭JanuarySnowstor


    Disruptive rainfall due tonight with possible lightning through midland areas.

    Surprised not a orange warning for rain



  • Registered Users Posts: 10,010 ✭✭✭✭Oscar Bravo


    Status Orange - Rain and thunderstorm warning for Leinster, Cavan, Monaghan, Tipperary, Waterford

    Met Éireann Weather Warning

    Heavy rainfall with embedded thunderstorms likely to cause flooding.

    Valid: 23:00 Thursday 27/10/2022 to 07:00 Friday 28/10/2022

    Issued: 09:44 Thursday 27/10/2022

    Updated: 17:15 Thursday 27/10/2022



  • Registered Users Posts: 7,072 ✭✭✭pad199207


    Not surprised. The air is thick with moisture out there. Very humid.



  • Registered Users Posts: 10,010 ✭✭✭✭Oscar Bravo


    Heavy rain corresponding to warning




  • Registered Users Posts: 2,866 ✭✭✭JanuarySnowstor


    Cork missing eventhough an onshore southeast gale coupled with high tide means only one thing for the morning imo



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  • Registered Users Posts: 2,866 ✭✭✭JanuarySnowstor


    The extreme stuff showing up on the radar to the South of Ireland. It should show its hand over the South first after midnight. Looks extreme to me and likely to cause a lot of surface flooding as it moves North.

    I differ to Met Eireann in that the orange alert should be for Munster and Connacht, not further East!

    Let's see what happens!



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