Uk Convective General Discussion & Forecasts - April 2012 Part 4

[MP-R]

Well the Beeb has the thunderstorm symbol over Bristol at 1pm tomorrow so it's definitely game over here already

[A.J]

same old same old...naff all for the West Midlands......where's the blunt knife?...I feel the need to slash my ankles!

[Sprites]

Todays convection may be reserved for kent sussex and surrey, the cloud and rain is ready to move into east anglia, unless this breaks it up....

[Coast]

Todays convection may be reserved for kent sussex and surrey, the cloud and rain is ready to move into east anglia, unless this breaks it up....

Morning storm fans!

Let's have a look at what other organisations are saying for today, ESTOFEX to start:

Storm Forecast

Valid: Fri 27 Apr 2012 06:00 to Sat 28 Apr 2012 06:00 UTC

Issued: Fri 27 Apr 2012 00:35

Forecaster: TUSCHY

A level 1 was issued for parts of Bulgaria and W-CNTRL Turkey mainly for large hail.

A level 1 was issued for N-CNTRL Spain, parts of France, far W/N-Switzerland and far SW-Germany mainly for large hail and severe wind gusts.

SYNOPSIS

Cut-off process atop the Bay of Biscay is well underway during the end of the forecast period. The cut-off low reveals only low-end shift to the south (towards Portugal/NW Spain), whereas the northern part of the ancient trough lifts out to the NE atop the N-Sea to Norway/Sweden.

Downstream of that feature, prominent cold-core low over Romania/Bulgaria drops further to the south, leaving behind a strengthening and westward expanding high pressure area over the Ukraine.

This results in a well defined baroclinic zone which runs from the Iberian Peninsula to Germany all the way to the Baltic Sea. No real net motion of that boundary is forecast from Spain to SW-France with a northward shift over Germany and Baltic Sea due to strengthening WAA regime, especially during the night hours.

UKASF:

Forecaster: Dan

Last Updated: 2012-04-26 23:04:00

Valid: 2012-04-27 00:00:00 - 2012-04-27 23:59:00

Areas Affected:

MDT: Suffolk, Essex, London, Home Counties, Salisbury Plain, Devon, Dorset

SLGT: East Anglia, Midlands, Home Counties, CS + SW England, SE Wales

Synopsis:

Very sharp upper trough with the main jet over southeastern Britain will generate a strong surface convergence zone, where the focus for convection exists.

Discussion:

To the south of a quasi-stationary occlusion, a few hundred J/kg CAPE are likely to develop in response to rising LSTs. During the day a strong convergence zone is simulated by most model output, although it's exact position remains a little uncertain - the general western side has good agreement, but over East Anglia there is more uncertainty as to it's position. Close monitoring of observations during Friday will be key to determining where the convergence will develop.

Nonetheless, along aforementioned CZ a line of heavy showers and thunderstorms are forecast to develop, in a favourable environment. With the jet aloft, some 70kts DLS will allow convection to become organised into a distinct line along the convergence, spanning from Dorset towards Suffolk. This line will remain almost stationary throughout the day, only very slowly drifting a little further southwards with time. As such any showers or storms that do develop will be very slow moving, giving large amounts of rainfall in localised areas and significantly increasing the risk of flash flooding.

Light, converging winds and >20kts LLS increases the risk of a funnel or tornado developing along the CZ, while hail perhaps >1.0cm in diameter is possible in stronger cells. The convergence line will gradually ease as daytime heating subsides during the evening hours. Slight concern is excessive cloud from occlusion debris which may hinder convection at times, but for now we remain optimistic of some good cloud breaks to allow insolation to increase SFC temps.

TORRO tend to be nearer the time of anything and nothing again from SkyWarn. I'll just go and get a load of charts for you to scroll through!!!!

[Lynxus]

Damn this is heavy rain.

Hopefully will clear away later.

Unlikely to see any storms today ( Then again even the days when I have been likely its been quiet )

Still.... Will be keeping an eye on the radar etc.

[Convective]

Clear sky bar a few scattered clouds.. Meant to be chilly though today. The temperature seems to be on the up though by Tuesday I believe.

[Coast]

Right, is anyone in for any convective weather today? Here are some indicators:

21st OWS showing Wales, the SW and some of the South :

Their lightning possibility charts again show the SW and Wales with more chances as the afternoon goes on:

General forecast has some storms in the SW toward the end of the afternoon (nothing before):

NW storm risk:

CAPE is virtually non existent

That convergence running SW to NE across South Western counties might be the feature to watch?

Nice colours within that area signifying a possible funnel or spout:

I think the rainfall chart shows the areas most likely to get anything quite well:

So my interest for today is the narrow band from Cornwall to East Anglia passing through London mid to late afternoon, with emphasis more to the West?

[Coast]

Enjoy what we have currently, looks like it's coming to an end for a while soon:

[Darren Bown]

Down at Thorpe park today so may catch some lively showers later in the day!

[Lynxus]

Already seeing some strike south of the IOW...

[Robbie Garrett]

Already some good looking CBs about in SE London

[NO LONGER POSTING]

Down at Thorpe park today so may catch some lively showers later in the day!

OMG! I can see that from my house! Have fun...Be safe and make sure you get there early!!! It gets PACKED!!! Don't go back through staines either if you are going back home...easily add 2 hours to your journey...

Already some good looking CBs about in SE London

Had a very heavy shower this morning with one rumble!!! I had a dream last night of thunderstorms sooo you never know

[chionomaniac]

With such a distinctive convergence zone today which will be slowly transfering slightly south as the day goes on, there must be a good opportunity for those able to chase along the zone. There could be localised flooding and photo chances to catch a funnel or two in stronger cells.

Here is the mid afternoon convergence zone.

[NO LONGER POSTING]

With such a distinctive convergence zone today which will be slowly transfering slightly south as the day goes on, there must be a good opportunity for those able to chase along the zone. There could be localised flooding and photo chances to catch a funnel or two in stronger cells.

Here is the mid afternoon convergence zone.

phahaha right over my house...The local river burst it's banks last night not extreme but flooded the lower parts of the field

[chionomaniac]

phahaha right over my house...The local river burst it's banks last night not extreme but flooded the lower parts of the field

At the moment the actual southern end of the convergence line looks angled more towards Dorset/ Hampshire rather than Cornwall.

Edited April 27, 2012 by chionomaniac

[Coast]

With such a distinctive convergence zone today which will be slowly transfering slightly south as the day goes on, there must be a good opportunity for those able to chase along the zone. There could be localised flooding and photo chances to catch a funnel or two in stronger cells.

It does look like a distinctive line today and quite a few people should be able to home in on it in their locality!

[Robbie Garrett]

OMG! I can see that from my house! Have fun...Be safe and make sure you get there early!!! It gets PACKED!!! Don't go back through staines either if you are going back home...easily add 2 hours to your journey...

Had a very heavy shower this morning with one rumble!!! I had a dream last night of thunderstorms sooo you never know

Ahaha, well that was some immense Shower, the roof of the bus on my way to college was soooo loud!! Some torrential rainfull, and showers getting going really really early this morning, let's hope to add another 2 or 3 thunderstorms to my total this year

[Norfolk Sheep]

Todays convection may be reserved for kent sussex and surrey, the cloud and rain is ready to move into east anglia, unless this breaks it up....

Yep, was nice and clear first thing, now we're under the default grey blanket

[NO LONGER POSTING]

feeling it today!!! come on baby!

[MP-R]

Hmmm, I'm skeptical about today. Some very unstable looking clouds around this morning and dead calm but the convergence zone looks a bit far south for here. We shall see though.

There are some pretty heavy radar returns up over Gloucestershire and surrounds at the moment, likelihood for some flooding there.

[chionomaniac]

It does look like a distinctive line today and quite a few people should be able to home in on it in their locality!

Evidence today of a strong LLJ heading Northeastwards feeding into the convergence zone. I can see it above my head and recognise it from chasing in America.

[Lynxus]

Evidence today of a strong LLJ heading Northeastwards feeding into the convergence zone. I can see it above my head and recognise it from chasing in America.

Pics or it didnt happen!

// Whats an LLJ ( or am I just being thick today )

[Eskimo]

Pics or it didnt happen!

// Whats an LLJ ( or am I just being thick today )

Low Level Jet

[Robbie Garrett]

Pics or it didnt happen!

// Whats an LLJ ( or am I just being thick today )

Ladies like jokes!!

[Supacell]

Well I am afraid that it is all just too far away for me today, especially considering I am at work until 4pm. Good luck all, and you can be safe in the knowledge that Supacell and his mobile storm shield will be a good 200-250 miles north of any storms today