21st July 2011 - Storm/convective Forecast, Discussion & Reports

[Staffordshire]

What are the chances for tommorow...

Edited July 20, 2011 by Staffordshire

[Chris K]

What are the chances for tommorow...

Looking at the MetO surface pressure charts, a trough is moving south during the daytime, but all weather forecasts ive seen so far are predicting fewer showers, some possibly heavy but generally lighter than today.

[Costa Del Fal]

What are the chances for tommorow...

Very little imo. Some heavy showers yes but im pretty sure a No for any thundery weather. Typical when the East has loads and when something finally comes West there is no Thundery element left. :lol:

[ZONE 51]

take a look at this chart...il be back...

[ZONE 51]

Estofex- yes we are included in a small risk of some action! and over a large area

[UKVoodoo]

Does including us in with the thunderstorm risk on Estofex mean we're looking for action in France first as a sign of anything possible in the UK or is it just for ease of explanation on the diagram ?

Sorry I do try to be as clued up as possible reguarding weather and the warnings but sometimes I miss the explanations of the more obvious and relevant info because I cant see the forest for the trees

[ZONE 51]

Does including us in with the thunderstorm risk on Estofex mean we're looking for action in France first as a sign of anything possible in the UK or is it just for ease of explanation on the diagram ?

Sorry I do try to be as clued up as possible reguarding weather and the warnings but sometimes I miss the explanations of the more obvious and relevant info because I cant see the forest for the trees

we have a trough inland, nothing imported.

the Estofex includes us as some of the heavierr downpours could contain thunder in them

see image cut out from their chart below-read the bit ive highlighted in blue.

heres our feature for thursday.

Edited July 21, 2011 by ElectricSnowStorm

[vortex_liam]

I see the cap is screwed on TIGHT

[Lynxus]

Cant see much happening today.

Yes we have a trough passing through over there isnt much else going on.

So yeah, Showers, Some possibly heavy. Slight risk of thunder.

Nothing worth noting here..

No convergence lines.. nada.

Storm risk is pretty minimal.

Meh

I recon theres a "chance" of something. Just depends on this trough.

[Coast]

Estofex- yes we are included in a small risk of some action! and over a large area

Morning all. Been looking out for some action for a couple of days now, so eyes down for a full house!!!!

UKASF:

Forecaster: Dan

Last Updated: 22:07 Wednesday, 20th July 2011

Valid: 00:00 Thursday, 21st July 2011 - 23:59 Thursday, 21st July 2011

Areas Affected:

C/W/S Scotland, NW England, Midlands, Wales, Home Counties and West Country

Synopsis:

A negatively-tiled upper trough will be located over Scandinavia and eastern Europe, whilst an upper ridge builds over the North Atlantic. Consequently, slightly unstable conditions will develop across the United Kingdom in a rather slack surface northerly airflow.

Discussion:

Diurnal heating is likely to aid convective potential, with a fair few scattered showers developing during the day. Forecast soundings indicate a dry layer above 600mb will inhibit deep convection, but shallow convection is still expected to produce a scattering of heavy showers. It is likely that local convergence zones, the remnants of an occluded front and local topography, or perhaps a combination of all three, will provide additional forcing and may develop an isolated thunderstorm.

The best potential is likely to be over Wales and the West Midlands with ELT's as low as -20C, but even here the risk of lightning remains severely limited. Extensive cloud cover may also inhibit noteworthy convection.

With light winds both at the surface and upper levels, and predominately N/NWerly, showers that do form will be slow moving and may give locally large rainfall accumulations. Weak DLS and LLS and CAPE of just 300 J/kg suggest the risk of any severe weather is very low. Showers that do develop will slowly decrease in coverage during the evening hours.

No forecast from SkyWarn, their overview stating:

Severe Weather Risk: Low

Heavy showers moving through Northeastern England, possibly continuing overnight. Elsewhere cloudy and cool with occasional showers, brighter and drier towards the end of the week.

Nothing for a while from TORRO.

Here's my round up of potential:

The UKMO interpretation has nothing of note

NOAA's aviation weather shows the South and South East, both the charts from 21st OWS and NOAA highlighting "Cindy" on her way

KO index not encouraging:

Convective cloud is there though

CAPE doesn't really get going until later in the day

Shear:

Convergence:

Rain:

LCL:

Lapse rates ok:

CIN

So not a huge potential, but what there is, is in a better place for Southerners today

[Lynxus]

Some convection around now as expected.

Some heavy showers to the east of the country.

[Jane Louise]

Morning all,

I'm wondering if I may be in luck today for a rumble or two.

The Met Office has Gloucestershire on a yellow warning for heavy rain today. Can't wait to see some rain for a change.

[Lynxus]

Morning all,

I'm wondering if I may be in luck today for a rumble or two.

The Met Office has Gloucestershire on a yellow warning for heavy rain today. Can't wait to see some rain for a change.

You and me both Jane.

This summer is turning into the worst evar!

[Harry]

You and me both Jane.

This summer is turning into the worst evar!

Hehe so is some of the spelling on this furom

[Lynxus]

Hehe so is some of the spelling on this furom

Were you meant to misspell that

[Costa Del Fal]

Very slim thunder risk today imo. Less than 30% chance id say. Same story tomorrow with heavy showers but very low thunder risk.

Edited July 21, 2011 by Blizzards

[Harry]

Were you meant to misspell that

Indeed

[Nick F]

Convective / Storm forecast - Issued 21/07/2011 10:30

Forecast Summary Map

Valid: 21/07/2011 10:00 - 22/07/2011 06:00

Headline: ...THERE IS A RISK OF THUNDERSTORMS FORECAST...

Synopsis

A ridge of high pressure lies to the west of the UK while upper trough extends south across the UK with surface low pressure to the E and NE of the UK ... bringing a slack and unstable northerly flow across England and Wales.

... ENGLAND and WALES ...

Upper trough extending down from the north will spread increasingly colder air aloft southwards behind shortwave trough moving south across England and Wales this afternoon ... which will steepen lapse rates. Greatest mositure is likely across England and Wales today, away from NE England, so here we are likely to see the greatest potential for thunderstorms to develop this afternoon, aided by large scale ascent aloft, insolation and local wind convergence in slack flow. Coverage of thunderstorms is a little uncertain given rather weak CAPE indicated by models, so electrical activity maybe rather isolated. However, high precipitable water values indicated towards Sern UK (PWATs of 25mm+) and slack steering winds, suggests heavy showers and storms will be slow-moving ... bringing the threat of localised torrential downpours with risk of localised flooding.

Also, the slack flow aloft, wind convergence and low LCLs will again be favourable for funnel development and perhaps even a brief weak tornado, more espeicially across Wales, Midlands and NW England.

[Lynxus]

Where is this trough now?

Im trying to find something thats causing the current line of showers from east to west.. This cant be it? Its too far south.,

[Dean E]

Just got quite a downpour from those developing showers over the south coast. Its been overcast with dark clouds above for about an hour, and just 5 minutes ago the heavens opened.

Going to be a strange but productive day weather wise I think!

[Marcus_surfer]

Looks interesting for Mid and South/East Wales later, hopefully some pretty lively showers to come

[DeepSnow]

Looks interesting for Mid and South/East Wales later, hopefully some pretty lively showers to come

I was just thinking the same thing

Looks good for us so fingers crossed we will get a little something later!

[tomp456]

its quite warm and humid here, the sun is trying to show itself, too.

[Andy Bown]

Showers getting going across S.Gloucs and N.Wilts heading slowly SSE. Having fixed my eyes on quite a heavy looking cell approx 20 miles to my NE

I hadn't expected anything until that arrived, however there is a developing TCu overhead with large drops falling from it.

Of course things may not turn thundery but it's going to be a very interesting afternoon on what is a good clean convective day - meaning there is

a lot of clear sky between the showers rather than low level murk beneath/around the showers.

[fromey]

afternoon all.

looking at the radar loop on rain today looks like a cell/shower has just built over swindon, anybody that way to confirm this?

fromey