Storm discussion: including convective possibilities

[risk of sleet]

Lashings of rain shown for W Scotland from Wednesday afternoon onwards according to latest GFS precip charts. Meto though seem to think this will be more W England, Wales.

[azores92]

Lashings of rain shown for W Scotland from Wednesday afternoon onwards according to latest GFS precip charts. Meto though seem to think this will be more W England, Wales.

at the moment, i reckon the warnings will retract back west tomorrow. i very much doubt at this current time that the midlands will see much action until friday at the earliest, and possibly only western wales/sw scotland/sw england will see any heavy rain on weds/thurs

[Roger J Smith]

Where is Sherman going to be on Saturday, that's the main clue to future developments.

[Mondy]

I can't remember how the gutter press named last weeks southern storm - something like "one in a 3 year event"??

If Saturday's progged low comes off, will they again issue the "one in a so many years event storm.."? I doubt it!

[Cookie]

Large divergence between the 'big three' models from the 12z output for Saturday and Sunday, ECM has a much shallower feature tracking NE across Ireland to Scotland, while UKMO has a slow moving low wallowing to the SW of Ireland both days.

So the jury's out for now ... until we get nearer in time, probably Weds-Thurs the models might have a better handle - though GFS seems quite persistent, but it maybe overdeepening its dartboard lows!

as usall, seem to get that quite a bit.

[Paul Sherman]

Where is Sherman going to be on Saturday, that's the main clue to future developments.

LOL @ Roger

Did any of you guys know that Saturday will be 28 years to the day since the Uk & Europe's biggest ever Tornado Outbreak, namely 21st November 1981 when 105 Tornadoes touched down in nearly every county of the Uk from Glamorgan to Kent, on that day a low to the SW Of Scotland and Incredibly Strong Cold Front headed South East during the afternoon and evening, they even had Hurricane Force winds in the North Sea as the low heading into the Continent.

The Camera will be with me this weekend whatever happens.

Paul S

[NL]

ESTOFEX have issued a level 1 risk for (potential) tornadoes.

...Ireland, UK...

At about 15Z an Atlantic shortwave trough with unstable air should arrive to this area, backed by a PV anomaly, and a jet (left exit) to its south. Although overlap with CAPE is small, with up to 35 m/s DLS and 15 m/s LLS interfering with any convection a potential for tornadoes exists. Over the North Sea, both convective and non-convective gusts could reach over 25 m/s.

http://www.estofex.org/

Edited November 17, 2009 by NL

[Coast]

ESTOFEX have issued a level 1 risk for (potential) tornadoes.

Nice!

Nothing from TORRO or UKASF yet. Pictures from the interweb:

I think this one has Jane Louise's name on it!!!

[maidstone weather]

Hot off the press from TORRO:

A TORRO CONVECTIVE DISCUSSION has been issued at 09:25GMT on Tuesday 17th November 2009

Valid from/until: 09:25 - 21:00GMT on Tuesday 17th November 2009 for the following regions of the United Kingdom & Eire:

Eire

N Ireland

N Wales

N England

Central and southern Scotland

THREATS

Wind gusts to up to 55mph; isolated tornadoes; isolated CG lightning; hail 10-15mm diameter.

SYNOPSIS

Upper trough in unstable airmass is producing an area of heavy showers/isol TS across western Eire ATTM. This will move ENE through today. Shear will be marginally sufficient for cell organisation/rotation. Thus, a risk exists for marginally severe wind gusts/hail, and perhaps a tornado.

Forecaster: RPK.

http://www.torro.org.uk/site/forecast.php

[Jane Louise]

Oh Coast, my turn will be in 2015 :cray:I've just got to be patient lol.

[dogs32]

Yesterday BBC forcast was for deluge of heavy rain or Showers for the North West..(Wales)

Hinting the rain could cause some problems later with flooding...

Edited November 17, 2009 by dogs32

[hobbielancie]

Strong winds are forecast for the East as well Weds and Thurs. Though I will believe it when I see it as we missed last weekend storms in Norfolk (again!) Bought a new Weather Station so looking forward to testing it out.

[A.J]

For us in the west/north midlands, there are some very bright echos on radar and odd sferics mixed in with this band of rain moving in from the west..Might be worth keeping one eye on the sky this evening :blink:

[multi cellular thunderstorm]

For us in the west/north midlands, there are some very bright echos on radar and odd sferics mixed in with this band of rain moving in from the west..Might be worth keeping one eye on the sky this evening :lol:

Same up here, there's some heavy showers further west with a few sferics.

Looks like it's heading right this way so hopefully an exciting drive home with downpours and lightning :blink:

[The PIT]

Well the next few days could be very interesting wind wise and possibly rainwise. Met office is extremely poor in predicting rainfall amounts so 120mm I would take with a pinch of salt. However if it does come off we could looking at flooding like we had in 2007 in parts of the country.

[dogs32]

Well the next few days could be very interesting wind wise and possibly rainwise. Met office is extremely poor in predicting rainfall amounts so 120mm I would take with a pinch of salt. However if it does come off we could looking at flooding like we had in 2007 in parts of the country.

Im glad you said that PIT.Someone else is thinking on the same lines

..I was so surprised how concerned Alex Deacon was with his forecast for problems leading to flooding..

Though things might still change and it might never happen as many times they dont

Edited November 17, 2009 by dogs32

[johnholmes]

Forecasters, professional or amateur, have little option but to warn when 2 models are suggesting similar totals over a similar period.

Human forecasting of rainfall totals was worse, and never beyond 12-24 hours ahead; believe me, I was there!

[The PIT]

Forecasters, professional or amateur, have little option but to warn when 2 models are suggesting similar totals over a similar period.

Human forecasting of rainfall totals was worse, and never beyond 12-24 hours ahead; believe me, I was there!

Most of the time they said heavy rain without specifying amounts. Until the technology gets better I prefer if they stop giving out amounts except to the emergency services and just forecast heavy rain. When Sheffield and South Yorkshire had the floods the first forecast was extremely accurate. The next two miles off. Got to admit at the time I did say the predicted amounts were unlikely as the two large amounts we already had so close together were almost unheard off so having three and then four was extremely unlikely.

[dogs32]

even though its interesting seeing these events...On this occasion its best if it doesnt happen as extreme flooding is dire for the people invoilved..

Best to keep a close eye on this one.

will be be watching this closely with what could or may not be

[PeterDoswell]

seems that there is some nasty weather along south coast tonight . shipping forecast 1725

Gale warnings - Issued: 1002 Tue 17 Nov

Southwesterly gale force 8 expected soon, increasing severe gale force 9 later

Shipping Forecast - Issued: 1725 Tue 17 Nov

WindSouthwesterly 6 to gale 8 increasing 7 to severe gale 9, perhaps storm 10 later.

Sea StateRough or very rough.

WeatherRain or squally showers.

VisibilityModerate or good.

[weatherobsuk]

The GFS had a area of developing winds out into the Southern North Sea by midnight, transitioning across to the Netherlands by 3am and then heading NE towards South Norway by early Weds Morning. Had the system been 6 hours earlier this same windfield would be developing around the Isle of Wight, heading up to London.

[multi cellular thunderstorm]

Same up here, there's some heavy showers further west with a few sferics.

Looks like it's heading right this way so hopefully an exciting drive home with downpours and lightning :lol:

Didn't quite get lightning but certainly plenty of heavy downpours on my way home.

Also I was quite surprised to see some sleet on my windscreen in one of the heavier birsts, I was at about 220m.

It could have maybe been soft hail breaking up but it certainly looked like sleet to me.

[Tom Lynch]

Large divergence between the 'big three' models from the 12z output for Saturday and Sunday, ECM has a much shallower feature tracking NE across Ireland to Scotland, while UKMO has a slow moving low wallowing to the SW of Ireland both days.

So the jury's out for now ... until we get nearer in time, probably Weds-Thurs the models might have a better handle - though GFS seems quite persistent, but it maybe overdeepening its dartboard lows!

Hi Nick

Everything seems to happening north of my present location La Rochelle. Any ideas as to where anything of interest might happen. I was going to head south and see if we could get into the sun. We might even go south and find a place with Sky so that we can watch Preston V Newcastle, that is on Monday.

Tom

[Nick F]

Hi Nick

Everything seems to happening north of my present location La Rochelle. Any ideas as to where anything of interest might happen. I was going to head south and see if we could get into the sun. We might even go south and find a place with Sky so that we can watch Preston V Newcastle, that is on Monday.

Tom

Hi Tom

Looks like any storm potential will remain N of you over Wern UK mostly for the foreseeable future with a ridge keeping the air stable over France. Though by Sunday might be some convective potential over Brittany.

Looking at the situation for Saturday, GFS still at odds with the Euros even at t+96 - with the Euros keeping the Atlantic trough further west and hence not the deep low GFS suggests battering Ireland and Scotland, though ECM still would be rather windy over Ireland. UKMO looks a little too far west with its prog on Saturday IMO - so I would go for something between GFS and ECM.

[Tom Lynch]

Hi Tom

Looks like any storm potential will remain N of you over Wern UK mostly for the foreseeable future with a ridge keeping the air stable over France. Though by Sunday might be some convective potential over Brittany.

Looking at the situation for Saturday, GFS still at odds with the Euros even at t+96 - with the Euros keeping the Atlantic trough further west and hence not the deep low GFS suggests battering Ireland and Scotland, though ECM still would be rather windy over Ireland. UKMO looks a little too far west with its prog on Saturday IMO - so I would go for something between GFS and ECM.

Thanks Nick

What I think you are saying is that unless you are back in the UK, head for somewhere with Sky tv so I can watch the match.

Tom