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Convective / Storm Discussion - 5th August onwards 2013

Jane Louise

By Jane Louise
in Storms & Severe Weather

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Guest William Grimsley

Guest William Grimsley

Posted
Posted

It looks like some quite active heavy/thundery showers will enter SW England on Saturday. It's something to watch.

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staplehurst Community Regular

staplehurst

Posted
  • Location: Norwich
  • Location: Norwich
Posted

 

 

SkyWarn, UKASF and TORRO also remaining stum so far (or enjoying the holiday season!) so what are the indications that have the BBC calling convection for today?

 

 

Been away for a few days over and either side of the weekend, but back now Posted Image

 

Tomorrow looks interesting...

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Coast Veteran

Coast

Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
Posted

Been away for a few days over and either side of the weekend, but back now Posted Image

 

I thought you might have been! Posted Image

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Coast Veteran

Coast

Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
Posted

I'll stick you forecast on for tomorrow then! Posted Image

 

 

post-6667-0-00709400-1377084628_thumb.jp

 

Synopsis

 
Upper trough, with axis over northern England at midnight, will track southeastwards through Thursday, becoming a cut-off upper low over the East Midlands by mid-afternoon. At the surface, advection of a warm and humid airmass will take place during Wednesday, with this airmass still present through Thursday. Meanwhile, a weakening cold front will continue to migrate southwards across England and Wales.
 
Discussion
 
Through the first half of this forecast period, an area of showery rain (from mid- and high-level cloud) is expected to develop across central and southern Britain, as a shortwave trough runs eastwards across these areas ahead of the advancing weak cold front. Very little lightning activity, if any, is expected from this.
 
During Thursday daytime, heating of the warm, moist surface airmass will generate 500-800 J/kg CAPE. With upper low aloft and low-level convergence/confluence (especially with aid from sea breeze development) and local topography, scattered showers and a few thunderstorms are forecast to develop, thunderstorms most likely in the SLGT area. Shear is rather weak (~20kts) so organisation of cells will be limited somewhat, and hence the risk of severe weather is considered fairly low. However, PWAT values of 30-35mm combined with slow storm motion may result in local flash flooding from prolonged downpours, while hail up to 1.5cm in diameter is possible from any stronger cells given dry air aloft. There may be the potential for a funnel given relatively low LCLs (especially during the late morning and again into the evening) and low-level convergence.

 

 

http://ukasf.co.uk/storm-forecasts/274

 

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Guest William Grimsley

Guest William Grimsley

Posted
Posted (edited)

I think we might have a storm on the way at the weekend.  Has anyone noticed the similarity?  Same ratios, same angles, same isobars.  Warm water, check.  Cold water, check.  Humidity, check.  It's like a balloon ready to pop.  And if it goes Saturday it's high tide at 1622, 4.1m in the South East so a surge towards London is a possibility.

 

Posted ImageKat2.png

Sorry, but oh my god! That's coming right at Newton Poppleford Weather and SW England! Posted Image

Edited by William Grimsley
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Guest William Grimsley

Guest William Grimsley

Posted
Posted

Tomorrow looks interesting...

Annoyingly, Newton Poppleford Weather is just too far SW of even the isolated area. :(

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wimblettben Rising Star

wimblettben

Posted
  • Location: Brongest,Wales
  • Weather Preferences: Stormy autumn, hot and sunny summer and thunderstorms all year round.
  • Location: Brongest,Wales
Posted

Annoyingly, Newton Poppleford Weather is just too far SW of even the isolated area. Posted Image

The risk seems to be higher for our area on Saturday so either way we should hopefully get something.

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Coast Veteran

Coast

Posted
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
  • Location: Eastbourne, East Sussex (work in Mid Sussex)
Posted

GFS currently have it in your general area:

 

Posted Image

 

Posted Image

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Cheshire Freeze Maestro

Cheshire Freeze

Posted
  • Location: Crewe, Cheshire
  • Weather Preferences: Snow, storms and other extremes
  • Location: Crewe, Cheshire
Posted (edited)

Seems the NAE has come round to the idea of showers breaking out tomorrow now on its 12z update. Midlands, C/N Wales and S Northern England look the areas at risk?

 

Posted Image

 

GFS 12z storm risk for tomorrow...

 

Posted Image

Edited by CreweCold
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Guest William Grimsley

Guest William Grimsley

Posted
Posted

The risk seems to be higher for our area on Saturday so either way we should hopefully get something.

Yes Saturday looks good.

I've just noticed a lot of showers getting going around the S and W coast of SW England. This could be interesting.

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Tim Bland Maestro

Tim Bland

Posted
  • Location: STEVENAGE, HERTS (100M ASL)
  • Location: STEVENAGE, HERTS (100M ASL)
Posted

Weatherpro (metro group ) which uses ECM data has a level 3 (highest) thunderstorm warning for Stevenage tommorow late evening. Never seen a level 3 before, during the major July storms it was a level 2. ECM fine detail must be showing a high risk!

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Supacell Accomplished

Supacell

Posted
  • Location: Belper, Derbyshire
  • Weather Preferences: Thunderstorms
  • Location: Belper, Derbyshire
Posted (edited)

Tomorrow looks good for some potent thunderstorms. Cooler air above a warm, humid airmass and a cold front moving in from the west. GFS 12z has upgraded CAPE for the Midlands area. Not much shear on offer so more than likely slow moving pulse storms, but where they do pulse up there could be some torrential rainfall and hail along with some decent lightning.

Edited by Supacell
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Guest William Grimsley

Guest William Grimsley

Posted
Posted

Weatherpro (metro group ) which uses ECM data has a level 3 (highest) thunderstorm warning for Stevenage tommorow late evening. Never seen a level 3 before, during the major July storms it was a level 2. ECM fine detail must be showing a high risk!

What is it showing for Devon?

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Guest William Grimsley

Guest William Grimsley

Posted
Posted

Tomorrow looks good for some potent thunderstorms. Cooler air above a warm, humid airmass and a cold front moving in from the west. GFS 12z has upgraded CAPE for the Midlands area. Not much shear on offer so more than likely slow moving pulse storms, but where they do pulse up there could be some torrential rainfall and hail along with some decent lightning.

Yes, nearly 1000 j/kg on offer for SE Midlands. Just a plain 50 j/kg for Newton Poppleford Weather.

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East_England_Stormchaser91 Veteran

East_England_Stormchaser91

Posted
  • Location: King’s Lynn, Norfolk.
  • Weather Preferences: Hot and Thundery, Cold and Snowy
  • Location: King’s Lynn, Norfolk.
Posted

Tomorrow looks good for some potent thunderstorms. Cooler air above a warm, humid airmass and a cold front moving in from the west. GFS 12z has upgraded CAPE for the Midlands area. Not much shear on offer so more than likely slow moving pulse storms, but where they do pulse up there could be some torrential rainfall and hail along with some decent lightning.

About time !! God this thread has been dead this year!

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Supacell Accomplished

Supacell

Posted
  • Location: Belper, Derbyshire
  • Weather Preferences: Thunderstorms
  • Location: Belper, Derbyshire
Posted

About time !! God this thread has been dead this year!

 

It has been a very poor year in general but for that 2 week spell at the end of July into the first couple of days of August. In that period I saw some of the best storms I have ever seen. We sure had to wait but for those that experienced the intensity of those storms the wait was worth it. Unfortunately we have reverted to waiting ever since though.

 

Must say I can't see tomorrow's storms being anything like as powerful as the 22nd/23rd July storms this year though, but even half as intense would still make a great storm :)

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cheese Veteran

cheese

Posted
  • Location: Leeds
  • Weather Preferences: snow, heat, thunderstorms
  • Location: Leeds
Posted (edited)

This year is a lot better than last year - because we actually got something.

Edited by cheese
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Raidan Enthusiast

Raidan

Posted
  • Location: BRISTOL
  • Location: BRISTOL
Posted

Just rained here and the people that were outside said they heard thunder,I think it was a plane to be honest and I haven't heard anything but there addiment it was thunder.

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wimblettben Rising Star

wimblettben

Posted
  • Location: Brongest,Wales
  • Weather Preferences: Stormy autumn, hot and sunny summer and thunderstorms all year round.
  • Location: Brongest,Wales
Posted

The sky definately does have that thundery type of look to it this evening.

 

Maybe a good sign of things to come for some areas tomorrow.

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Guest William Grimsley

Guest William Grimsley

Posted
Posted

The sky definately does have that thundery type of look to it this evening.

I was thinking the same thing.

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Summer Sun Maestro

Summer Sun

Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington
Posted (edited)

Synopsis

 

Upper trough, with axis over northern England at midnight, will track southeastwards through Thursday, becoming a cut-off upper low over the East Midlands by mid-afternoon. At the surface, advection of a warm and humid airmass will take place during Wednesday, with this airmass still present through Thursday. Meanwhile, a weakening cold front will continue to migrate southwards across England and Wales.

 

Discussion

 

Through the first half of this forecast period, an area of showery rain (from mid- and high-level cloud) is expected to develop across central and southern Britain, as a shortwave trough runs eastwards across these areas ahead of the advancing weak cold front.

During Thursday daytime, heating of the warm, moist surface airmass will generate 500-800 J/kg CAPE. With upper low aloft and low-level convergence/confluence (especially with aid from sea breeze development) and local topography, scattered showers and a few thunderstorms are forecast to develop, thunderstorms most likely in the SLGT area. Shear is rather weak (~20kts) so organisation of cells will be limited somewhat, and hence the risk of severe weather is considered fairly low. However, PWAT values of 30-35mm combined with slow storm motion may result in local flash flooding from prolonged downpours, while hail up to 1.5cm in diameter is possible from any stronger cells given dry air aloft.
There may be the potential for a funnel given relatively low LCLs (especially during the late morning and again into the evening) and low-level convergence.

 

http://ukasf.co.uk/storm-forecasts/274

Edited by Summer Sun
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ChezWeather Experienced

ChezWeather

Posted
  • Location: Chesterfield, Derbyshire, 110m
  • Location: Chesterfield, Derbyshire, 110m
Posted

Looks like there may be a chance for me tomorrow! been a very boring spell since the end of July here. 

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