Storm & Convective Discussion - SPANISH PLUME - 30/06/15 onwards

[VillagePlank]

40C in mid France and Spain today. My Aunty and Uncle in Greece have been issued with a public warning this morning and businesses are being advised to remain closed.

 

 

Along with the banks!!

Thunderstorm warnings out from the met office

 

Issued at: 1026 on Tue 30 Jun 2015

Valid from: 1600 on Wed 1 Jul 2015

Valid to: 2350 on Wed 1 Jul 2015

 

Isolated heavy, and possibly severe thunderstorms are expected to develop late Wednesday afternoon across parts of Northern England and Southern Scotland. Some torrential downpours are possible leading to localised surface water flooding, with hail and frequent lightning also possible hazards. The public should be aware that there is a chance of some very localised significant disruption.

 

Chief Forecaster's assessment

 

By Wednesday, a hot and increasingly humid airmass is expected to be in situ across much of the UK. This airmass looks conducive to isolated thunderstorm development during the afternoon and into the evening. With large amounts of energy available in the atmosphere, storms could be severe, with torrential downpours and hail of up to 1cm in size. 20-30 mm of rain is possible in less than an hour, with as much as 60 mm possible in 3 hours very locally. Large uncertainty remains regarding areas most at risk from storms, and many areas will miss these altogether and stay dry. However, where they do develop, very localised significant disruption is possible.

 

http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1435705200&regionName=uk

 

Almost certainly that's going to be updated as we go through today, and tomorrow.

[toggerob]

NMM has initiation of the storms much farther south and centralized that the MetO suggests, storms breaking out west to east from Wrexham to Burton-upon-Trent.

[Harry]

Along with the banks!!

 

Almost certainly that's going to be updated as we go through today, and tomorrow.

 

Would certainly expect that to expand northwards.

 

Hope you're optimism is correct VillagePlank...soul destroying when these setups come along and fail to detonate.

[ChezWeather]

Wednesday

UKMO seemingly agreeing with this sort of precip for now 

 

Could all shift South and East yet

Edited June 30, 2015 by ChezWeather

[Pat Butcher]

Up to Saturday morning from here http://www.meteociel.fr/modeles/wrfnmm.php?ech=96&mode=1&map=0

 

Wow, tomorrow afternoon/evening is absolutely exceptional on that model, storms running east to west across the spine of northern mainland Britain. Less so on GFS but more than enough energy to kick off.

 

I'll be interested to see what the experts (Nick F, Estofex) make of the severe threat. The models definitely don't scream tornadoes however there's hugely significant disagreement (see the two 0-6km shear models).

[Harry]

06z GFS still keen on storms developing into the SE tomorrow...hmmmmm!!

Edited June 30, 2015 by Harry

[Greeny]

I haven't been chart watching for that long but I haven't seen theta-E values this high before

[Mapantz]

Forecasts and warnings exactly what I expected.

I'm a little surprised that parts Southern Scotland are not in the MetO warning. I remember a similar situation a few years ago, some nasty cells erupted and caused flash flooding.

Friday still looks interesting in the South/Southeast, though.

Edited June 30, 2015 by Mapantz

[Chris K]

Can't believe I'm too far South to see any storms, let alone too far west

 

At least I can enjoy the fantastic weather I guess! Just wanted it to end with some fireworks which doesn't currently look very likely IMBY...

[VillagePlank]

Would certainly expect that to expand northwards.

 

Hope you're optimism is correct VillagePlank...soul destroying when these setups come along and fail to detonate.

 

Yes, quite. The trigger is everything - even a loaded gun situation with the CIN that's around.

[ChezWeather]

Can't believe I'm too far South to see any storms, let alone too far west

 

At least I can enjoy the fantastic weather I guess! Just wanted it to end with some fireworks which doesn't currently look very likely IMBY...

I wouldn't worry yet, we've seen time and time again that the models can get it wrong, remember they are only a guideline 

 

Plenty of time for change before tomorrow 

[sn0wman]

Thunderstorm warnings out from the met office

 

Issued at: 1026 on Tue 30 Jun 2015

Valid from: 1600 on Wed 1 Jul 2015

Valid to: 2350 on Wed 1 Jul 2015

 

Isolated heavy, and possibly severe thunderstorms are expected to develop late Wednesday afternoon across parts of Northern England and Southern Scotland. Some torrential downpours are possible leading to localised surface water flooding, with hail and frequent lightning also possible hazards. The public should be aware that there is a chance of some very localised significant disruption.

 

Chief Forecaster's assessment

 

By Wednesday, a hot and increasingly humid airmass is expected to be in situ across much of the UK. This airmass looks conducive to isolated thunderstorm development during the afternoon and into the evening. With large amounts of energy available in the atmosphere, storms could be severe, with torrential downpours and hail of up to 1cm in size. 20-30 mm of rain is possible in less than an hour, with as much as 60 mm possible in 3 hours very locally. Large uncertainty remains regarding areas most at risk from storms, and many areas will miss these altogether and stay dry. However, where they do develop, very localised significant disruption is possible.

 

Areas under the warning

 

East Ayrshire, South Ayrshire, South Lanarkshire

 

Dumfries and Galloway, Scottish Borders

 

Conwy, Denbighshire, Flintshire, Wrexham

 

Blackburn with Darwen, Blackpool, Cheshire East, Cheshire West and Chester, Cumbria, Greater Manchester, Halton, Lancashire, Merseyside, Warrington

 

Darlington, Durham, Gateshead, Hartlepool, Middlesbrough, Newcastle upon Tyne, North Tyneside, Northumberland, Redcar and Cleveland, South Tyneside, Stockton-on-Tees, Sunderland

 

East Riding of Yorkshire, Kingston upon Hull, North Lincolnshire, North Yorkshire, South Yorkshire, West Yorkshire, York

 

Derbyshire

 

http://www.metoffice.gov.uk/public/weather/warnings/#?tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1435705200&regionName=uk

Very strange that they haven't put Central Scotland under the warning. Models are currently showing some of the most intense thunderstorms over this area.

[matty40s]

Just gone over 27 in Leicester.

[Chris K]

I wouldn't worry yet, we've seen time and time again that the models can get it wrong, remember they are only a guideline 

 

Plenty of time for change before tomorrow 

 

Yes you are of course right, but last time the models were showing storms for the W Country whereas the MetO were having none of it. Going by their forecast it looks like staying settled here...for now! Fingers, toes and bum cheeks crossed it doesn't 

Edited June 30, 2015 by Chris K

[Staffordshire]

Just gone over 27 in Leicester.

are you sure? Seems pretty exceptional for 11:50 considering that was pretty much the forecast high for that area today

[Chris.R]

are you sure? Seems pretty exceptional for 11:50 considering that was pretty much the forecast high for that area today

Well it's 26.8 here

[Flash bang flash bang etc]

So basically I guess the synopsis is this:

"Scotland will definitely get one storm at least - but nobody really knows where. Also, today is bright with clear skies - but it could thunder if there are clouds - but we don't know exactly where those clouds might be. Also the front might go east (but we don't know for sure) - and we definately don't know where it is or where it is likely to come from. And for the South of the UK it is highly likely we don't know when you will get storms."

[AL.]

Swindon currently 24C, with heat building every day and not a lot of cooling during the evening I'm sure there's going to be some big storms about soon.

[Jan]

Well it's 26.8 here

I can confirm that Chris, showing 26c/27c here

[Methuselah]

So basically I guess the synopsis is this:

"Scotland will definitely get one storm at least - but nobody really knows where. Also, today is bright with clear skies - but it could thunder if there are clouds - but we don't know exactly where those clouds might be. Also the front might go east (but we don't know for sure) - and we definately don't know where it is or where it is likely to come from. And for the South of the UK it is highly likely we don't know when you will get storms."

That about sums it up, FB...Almost always the way with thunderstorms...

[Trickster]

Well which model do I choose for this area?

 

GFS has storms here at midnight

Met Office have storms at 3am

ECM have storms at 6am

 

Definitely will be watching the radar closely this evening

[Nick F]

Heads up for next few days, have done storm forecasts for today and tomorrow:

 

DAY 1 CONVECTIVE OUTLOOK

 

 

... SYNOPSIS ...

An amplified upper pattern on Tuesday see a slow-moving upper trough extending S to the W of the UK and a an upper ridge extending N from the central med to central Europe. A plume of hot and increasingly moist air will spread N across the UK Tuesday,  the plume destabilising along across Nern and Wern areas later.

 

...  N WALES, N ENGLAND , N. IRELAND and S and E SCOTLAND ...

 

Very warm and increasingly moist southerly flow combined by weaker heights and cooler temperatures aloft across northern and western Britain will allow 400-700 j/kg CAPE to build this afternoon across the above areas as peak heating occurs. Isolated heavy showers and thunderstorms are forecast to develop and drift north during the evening before clearing NE Scotland in the early hours.  20-30knts of DL shear may allow any storms to organise to produce some hail, gusty winds and torrential rain leading to flash flooding.

 

... SW/CENTRAL S ENGLAND , W MIDLANDS, WALES and IRISH SEA COASTS ...

 

An elevated mixed layer (EML) plume characterised by steep lapse rates is expected to spread N across SW/S England, Midlands, Wales and Irish Sea tonight, with MLCAPE in the order of 700-1000 j/kg CAPE indicated with this EML plume. Lift of unstable plume from a shortwave trough moving N/NE from the Bay of Biscay across the SW/W and central UK will allow isolated elevated storms to develop and drift north across the above areas overnight, with a risk of hail and frequent cloud-to-ground lightning.

 

---------------------------------------------------------------------------------------------------------------------------------------------------------

 

DAY 2 CONVECTIVE OUTLOOK

 

 

... SYNOPSIS ...

 

A plume of hot and increasingly moist air will be in place across much of the UK on Weds, the plume becoming increasingly unstable across northern, central  and western areas of the UK, as upper trough to the west moves closer allowing heights and pressure to fall, with a more widespread risk of thunderstorms from The Midlands north and west.

 

... WALES, MIDLANDS, N ENGLAND, N IRELAND and SCOTLAND ...

 

Overnight isolated elevated thunderstorms drifting north across the SW and W maybe ongoing across The Midlands, Wales and NW England in the morning, as a short wave trough continues N and NE across SW/W Britain. Thunderstorms are then expected to develop more widely across the above areas, particularly northern England northwards through the afternoon, as surface heating of the humid airmass into the high 20s deg C generates 1500-2000 j/kg SBCAPE beneath an EML which will likely be overcome by sea breeze convergence inland, orographic forcing and forcing from shortwave moving N/NE. Increasingly strong southerly jet shifting slowly east and sfc winds backed SEly will generate 40-50 knts of DL shear and will support organisation of thunderstorms, with bowing line segments and possibly supercells, perhaps eventually merging into NE moving MCS, these storms capable of producing the full range of severe weather risks. Large hail and damaging wind gusts are possible, along with sufficiently strong low-level shear indicated for the development of one or two tornadoes, if storms become surface-based. Other hazards will be torrential rain leading to flash flooding. Therefore have issued a MARGINAL and SLIGHT risk of severe weather.

 

... ELSEWHERE ...

 

The highest risk of thunderstorms will be from the Midlands north on Wednesday, but there is a risk of one or two isolated thunderstorms developing further south across central southern England  triggered by high temps. Also a risk later on into the overnight period of storms pushing over the Channel from France. All with a risk of severe weather too, but this is covered by a general thunderstorm area for now.

Edited June 30, 2015 by Nick F

[Paul Sherman]

Great Update Nick, Also Torro just updated and pretty much the same as Nick/Netweather

 

Possibility of Marginal Supercell Structures tomorrow near Scotland, with a more general risk of an MCS Moving up from La France for SE & East Anglia into early hours of Thursday morning.

 

The possible really nasty stuff could be in store for Friday, more on this next 24-48 hours 

[StormChaseUK]

Thanks Nick,  I think it will be the type of evening those in the NW will see distant flickers of lightning from Anglesey direction.

[Harry]

Great Update Nick, Also Torro just updated and pretty much the same as Nick/Netweather

 

Possibility of Marginal Supercell Structures tomorrow near Scotland, with a more general risk of an MCS Moving up from La France for SE & East Anglia into early hours of Thursday morning.

 

The possible really nasty stuff could be in store for Friday, more on this next 24-48 hours

Hi Paul, are you seeing potential for early hours imports Thursday then?

I'm just not seeing it