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Convective/Thunderstorm Discussion Autumn/Winter 2018/2019

  • 18-09-2018 3:21pm
    #1
    Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,101 Mod ✭✭✭✭ DOCARCH


    A new thread for Autumn/Winter....surprised we got so far into September without one!

    Anyway....

    A few sparks showing up this afternoon in the midlands/north Offaly area.


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Comments

  • Registered Users Posts: 1,713 ✭✭✭ Bsal


    Strong pileus or cap cloud formation about 30min ago near Swords

    5069079b1fd35c5493237a2e8a821074.jpg


  • Registered Users Posts: 663 ✭✭✭ Ilyushin76


    Loads of activity of the west coast wonder will it make it as-far as land?


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,101 Mod ✭✭✭✭ DOCARCH


    Quite a lot of sferics showing up now in (off) Galway and Mayo. http://en.blitzortung.org/live_lightning_maps.php?map=12


  • Registered Users Posts: 9,391 ✭✭✭ Oscar Bravo


    Anyone in Mayo, look out west. what a show!


  • Registered Users Posts: 1,733 ✭✭✭ sunbeam


    Intermittent thunder and lightning here in Achill for the past hour. Seems to be intensifying now as the wind increases.


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  • Registered Users Posts: 578 ✭✭✭ Dank Janniels


    Blue flashes in north east Galway around Dunmore+ Glenamaddy, heavy hailstone showers afterwards, dying down abit now


  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    Heavy showers across Northern counties tomorrow some of which may become electrified.

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  • Registered Users Posts: 47,641 ✭✭✭✭ km79


    Just after driving to Shannon along motorway from Galway
    Treated to an unexpected light show to the south west of Ardrahan and Gort
    5 huge flashes over that stretch of the journey


  • Registered Users Posts: 6,440 ✭✭✭ pad199207


    Fabulous convection displays to my S and SE


  • Registered Users Posts: 663 ✭✭✭ Ilyushin76




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  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    Some convective set up possible tomorrow , sporadic lightning a low possibility, maybe more so over water close to coasts , in the S, SE perhaps, low possibility later in the W ? Heavy rain again along the S tomorrow.

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  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


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    Convective Weather.co.uk

    Day 2 Convective Outlook
    VALID 06:00 UTC Tue 06 Nov 2018 - 05:59 UTC Wed 07 Nov 2018

    ISSUED 21:25 UTC Mon 05 Nov 2018

    ISSUED BY: Dan

    A complicated upper pattern exists on Tuesday, with an upper low over the Pyrenees weakening allowing elements of upper forcing to be drawn northwards across the British Isles on the forward side of the main Atlantic upper trough. At the same time, the next Atlantic upper trough will pivot such that it becomes more negatively-tilted as it crosses Biscay on Tuesday night into SW England by Wednesday morning.


    Through Tuesday daytime, elements of elevated convection from mid-level instability release will produce some sporadic bursts of showery rain across some central and eastern parts of the British Isles - but similar to Monday, the risk of lightning is considered very low (below 5%), and hence no threat level has been issued.

    A series of frontal zones will provide pulses of occasionally heavy rain northwards over Ireland and western Britain throughout this forecast period, which may produce some localised sporadic lightning, but the vast majority will probably remain lightning-free at this point.
    The main interest is during Tuesday evening and night as stronger upper forcing approaches, overlapping warm, moist low-levels (and atop warm SSTs), helping to generate 400-700 J/kg CAPE. Cyclogenesis is also expected to occur close to or over SW England, encouraging a wrap-around occlusion to develop. Given this environment, an increase in lightning activity seems likely amongst a rather messy precipitation pattern. Strong gusts of wind and hail up to 1.5cm in diameter will be possible with the most intense cells, while an isolated tornado cannot be ruled out. There is a risk of localised flooding where convergence zones develop across SW England and/or west Wales, providing prolonged heavy downpours.


  • Registered Users Posts: 5,068 ✭✭✭ Iancar29


    An interesting forecast for this evening and tonight.
    A shortwave trough passes near to the south coast bringing a chance of organised convective cells with some sparodic lightning.
    00z
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    03z
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    With both good deep and low level shear, some lined squall segments with hail is possible, even a weak funnel cloud.
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    Pity its due during the hours of darkness, however.



    May set the alarm once or twice thought just to have a peak at the radar. :rolleyes:


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,101 Mod ✭✭✭✭ DOCARCH


    Quite a lot sferics south of Ireland atm, down towards Bay of Biscay.

    http://en.blitzortung.org/live_lightning_maps.php?map=10


  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    Heavy showers going through here in Kerry. Looks like some good convection from Satellite and cloud top charts show temps of about -40 to -50C . Will see if we get enough forcing to produce a few sparks. Would imagine best potential over the sea near the S and SE coasts, the relatively warm SST's aiding instability perhaps.

    Charts showing convective potential at times over the coming days.


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  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    Some firing off well to the S earlier , bit quieter now off Ireland but some nice bow echos from active squall lines off the UK and France.


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  • Registered Users Posts: 9,391 ✭✭✭ Oscar Bravo


    Nice few flashes up along the west coast now


  • Registered Users Posts: 663 ✭✭✭ Ilyushin76


    Lots of strikes showing off the west coast now, will they make it as far as land I wonder :D


  • Registered Users Posts: 2,523 ✭✭✭ Darwin


    Shannon airport TAF giving 30% probability of a thunderstorm for a couple of hours from midday:

    Probability 30% :
    Temporary
    from 09 at 12 UTC to 09 at 16 UTC
    Visibility: 4000 m
    Broken clouds at a height of 1000 ft
    Broken clouds at a height of 1800 ft, Cumulonimbus.
    thunderstorm, rain


  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    Potential there but behind the main rain bands for the most part ,some thundery showers perhaps in the W , SW later under a passing trough. Good lapse rates, shear even though the uppers are not particularly cold.


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  • Registered Users Posts: 9,391 ✭✭✭ Oscar Bravo


    Strikes getting close to the coast near Dingle now


  • Registered Users Posts: 2,134 ✭✭✭ lolie


    Estofex have gone with a level 1 for Ireland today.

    2018111006_201811082338_1_stormforecast.xml.png
    The sharp cold front of the Atlantic cyclone will cross Ireland in the 11 to 18 UTC time frame. Forecast models agree on marginal CAPE and a very strong wind field with up to 20 m/s shear and up to 400 m^2/s^2 storm-relative helicity across the lowest kilometer, respectively. Supported by strong lift ahead of the new Atlantic short-wave trough, a cold frontal rainband could form. Severe wind gusts are possible, and one or two tornadoes are not ruled out in case discrete stronger updrafts form within such a line. It is questionable if convection will be deep enough to produce lightning, though, hence only a level 1 is issued.
    The cold front will encounter more stable air along its further path over England and Scotland and any remaining convection will gradually weaken. Scattered to widespread, non-convective severe wind gusts are still possible in the warm sector and along the cold front, but they are not reflected by the ESTOFEX threat level scheme.
    Scattered postfrontal showers will gradually grow deeper and might produce a little lightning over the Celtic Sea towards the end of the forecast period, but by then the wind field should relax enough to keep the wind gusts below 25 m/s.


  • Registered Users Posts: 17,664 ✭✭✭✭ JCX BXC


    2s6o7i9.jpg

    Interesting looking feature starting to show.


  • Registered Users Posts: 5,847 ✭✭✭ pauldry


    Just seen this feature and looked for this thread. So far only gusty winds and heavy rain in Sligo but maybe Galway got an extra boost!


  • Registered Users Posts: 17,664 ✭✭✭✭ JCX BXC


    pauldry wrote: »
    Just seen this feature and looked for this thread. So far only gusty winds and heavy rain in Sligo but maybe Galway got an extra boost!

    Died out before reaching Galway.


  • Registered Users Posts: 5,454 ✭✭✭ Storm 10


    I have never seen the sky as black from a front that is approaching Galway from the West now, its pit black and gone very dark.


  • Registered Users Posts: 17,664 ✭✭✭✭ JCX BXC


    Storm 10 wrote: »
    I have never seen the sky as black from a front that is approaching Galway from the West now, its pit black and gone very dark.

    Yup, very dark, currently caught outside in it :)

    Some streetlights have actually turned on.


  • Registered Users Posts: 6,440 ✭✭✭ pad199207


    Anyone confirm thunder and lightning North Wexford?


  • Registered Users Posts: 5,358 ✭✭✭ highdef


    pad199207 wrote: »
    Anyone confirm thunder and lightning North Wexford?

    5 lightning strikes have been picked up in North Wexford.


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  • Moderators, Science, Health & Environment Moderators Posts: 10,453 Mod ✭✭✭✭ Meteorite58


    IMO Entering a period of instability in the atmosphere over the next couple of days with the passage of numerous troughs and a colder pool of upper air. Probably mostly seeing sferics over the sea with the relatively warm SST's assisting convection and with a fair amount of shear and high lapse rates. Clear spells helping diurnal heating. Showers moving in a SW to NE surface wind direction mainly falling on S and W coasts that might become weakly electrified and produce some lightning ( probably low chance ) and possible hail. If anything some good cloudscapes with blue skies tomorrow :)

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This discussion has been closed.
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