227 replies to this topic

[Blizzards]

18z GFS is even worse. I certainly have my doubts now about this week...

Edited by Blizzards, 01 August 2011 - 21:55 .

[Nick F]

Convective / Storm forecast - Issued 01/08/2011 22:30



Valid: 02/08/2011 10:00 - 03/08/2011 06:00

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

Synopsis
A large low pressure system in the Atlantic to the west of the UK and ridge over central southern Europe on Tuesday ... draws a warm moist and increasingly unstable S to SW flow across the UK. At 12z, slow-moving cold front expected to lie from Penzance - Manchester - Inverness, front decays in situ by 00z Weds.

... MIDLANDS, NERN and E ENGLAND, S SCOTLAND ...

Falling heights downstream of large upper trough and slightly cooler air advection above warm moist Tm airmass to east of cold front across the west will lead to some modest destabilisation during Tuesday afternoon - enhanced by strong surface heating and wind convergence likely ahead of weakening front ... particularly from The Midlands north into Sern Scotland. So here the development of isolated to scattered thunderstorms are possible during the afternoon and early evening during peak surface heating. Given rather weak vertical shear is indicated, no organised severe weather is likely to evolve. However, given rather high precipitable water values indicated (up to 30-33mm) - there is some concern of some localised torrential downpours with a risk of flash flooding.

Issued by: Nick F - Forecaster for Netweather

Also can be found here: http://www.netweathe...onvective;sess=

[NUT]

Latest updates are less encouraging does seem awful touch and go.........we could well miss out just

[anvilhead]

seems to be something heading for the IOW right now, doesnt look massively potent, but its building

[ElectricSnowStorm]

anvilhead, on 01 August 2011 - 23:51 , said:

seems to be something heading for the IOW right now, doesnt look massively potent, but its building

i am keeping a watch on this one! and keep check on the stuff in the SW!

i think this has the potential to blow into a thunderstorm when it hits the shores..

Edited by ElectricSnowStorm, 02 August 2011 - 00:34 .

[ElectricSnowStorm]

They have reached our shores, just along the South coast but no thunder or lightning going by Blitzortung detector. a few showers inland developing around the SE , and a lot of heavy ppn in other areas to, but no lightning detected.

some incredible convective cloud building to my south now! can see rain streaks!

[ElectricSnowStorm]

this one must be heavy, all lit up orange with rain streaks and its about to hit London, looks very heavy but not shown on radar yet, these shower could grow as sun rises!

it looks amazing, must be local as cant see on radar any heavy stuff around Surrey, il check rain today.

[ElectricSnowStorm]

just arrowed the one that brushed here and with another coming in..


ok last one but i just have to show the Southeasterners this...

we have something interesting going on here..

im looking at big convective cloud going up around here

Edited by ElectricSnowStorm, 02 August 2011 - 05:00 .

[ElectricSnowStorm]

The GFS 00z(new morning update!) is good if you like thunderstorms and intense downpours, not for everyone, but il leave it to others to post on this as i have to go now, another hot day in places with a humid feel with high dew points in places.

Edited by ElectricSnowStorm, 02 August 2011 - 05:22 .

[Chris K]

Tiny bit fresher outside this morning with drizzle. Looking through the gaps in the cloud I can see towers building already
I think some you guys in east/ne could be looking at some fun...maybe.

[Reevesie1]

Absolutely throwing it down in Central London. Caught everyone ... myself included ... by surprise. Rivers in the street style rain

[Coast]

Jane Louise, on 01 August 2011 - 20:42 , said:

A potent short-wave trough will be moving from N Iberia across the Bay of Biscay towards UK, pushing an EML into France. Nothing from UKASF yet, but I'm sure Stuart will post up when its out. Can't seem to post the image up ,will keep trying for you Staffordshire.

Morning all!, here's the piccies to go with ESTOFEX and UKASF:

Quote

Forecaster: Dan
Last Updated: 22:29 Monday, 1st August 2011
Valid: 00:00 Tuesday, 2nd August 2011 - 23:59 Tuesday, 2nd August 2011
MDT: SE Scotland, NE England and E Midlands
SLGT: E Scotland, N England, Midlands, W Country, East Anglia and Home Counties
Synopsis:

An upper ridge continues to strengthen to the east of the United Kingdom, whilst a quasi-stationary cold front will straddle W-C Britain. The main bulk of any noteworthy convective activity will be along and to the east of this frontal boundary.
Discussion:

High WBPT's continue to be advected northwards across C and E Britain during the forecast period, associated with a warm and humid airmass. Diurnal heating will allow a few hundred J/kg CAPE to develop, providing an environment favourable for convective initiation. In fact, due to the more widespread coverage of insolation compared to Monday, lightning is more likely to occur.

Scattered thunderstorms will develop in a weakly-sheared environment. ELT's as low as -35C are possible which would allow some decent deep convection to develop, particularly aided by topographic uplift and thus those areas to the east of high ground, based on a predominant southwesterly wind, will be at greatest risk of thunder and lightning. Severe weather is unlikely although some small hail and locally large rainfall totals are possible during some slow-moving storms.

Current thinking is that thunderstorms will initially develop over NE England/E Scottish Borders through the morning, and this development will then extend further south towards The Wash during the afternoon. Storms that do develop will pulse NEwards over the North Sea, where they will slowly decay during the evening.

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[gottolovethisweather]

Just posted this in response to Nick F's comments in the recent status updates.


Indeed, saw those on the NW radar and there was some local AcCas here in Newbury too. The skies are clearing well towards the west as far as I can see and with the sun getting to work, quite a few folk COULD GET LUCKY! Bring on the TL and perhaps we should keep our eyes on the stuff currently over France.

Let's all just keep our fingers crossed and maybe just maybe I'll add to my poor tally of 3 Thunder days, all of which have been pretty pitiful.

Thundery Cheers

gottolovethisweather

Edited by gottolovethisweather, 02 August 2011 - 06:44 .

[Coast]

and a few more charts to see what may be in store for today:







Nice orange blob smack bang in the middle of the country later:

Critical values KO.

> 6: no potential risk thunderstorms.
2-6: small potential risk for thunderstorms.
< 2: potential risk for thunderstorms.



Some critical values for the Soaring Index.

15-20: isolated showers, 20% risk for thunderstorms
20-25: occasionally showers, 20-40% risk for thunderstorms
25-30: frequent showers, 40-60% risk for thunderstorms.
30-35: 60-80% risk for thunderstorms.
>35 : >80% risk for thunderstorms.



Have we got enough CAPE and shear though?









A bit of rain through the day in places:



Lapse rates nothing special:





TBH, I see a day a bit like yesterday - not huge potential, but worth keeping an eye on the middle and slightly East of the country late afternoon.

[Harry]

About to drive through the only downpour I'm likely to see. Looks v much like a decaying storm, v elevated with nice features

[Harry]

www.sat24.com

Already some potent storms erupting over S of France...the low responsible is tracking North so hopefully will deliver something later....sheer fantasy I know but it'll be nice watching the satellite today any rate. I have just had this gut feeling for the past few days that the low could track further north and throw something towards S England, contrary to almost every model/forecast going...then again, pretty much every model, chart and forecast was breaking out thunderstorms across C/S England on 27th June which didn't materialise either....

Edited by Harry, 02 August 2011 - 07:51 .

[Static Prevails]

Harry, on 02 August 2011 - 07:49 , said:

www.sat24.com

Already some potent storms erupting over S of France...the low responsible is tracking North so hopefully will deliver something later....sheer fantasy I know but it'll be nice watching the satellite today any rate.

It also shows cloud starting to thin a little and break up, meaning more sunshine and therefore more chance for convection.

Certainly a day to keep an eye on.

[Coast]

Harry, on 02 August 2011 - 07:49 , said:

Already some potent storms erupting over S of France....

France looks like it will cop a big one today with Benelux countries and Germany getting the bulk of the action tomorrow. I'm holding out for any imports or something home grown, but the chances have receded a little. Anyway, fingers crossed!

[NUT]

Still the same this morning really for us up here. SE Scotland could get something but looks unlikely here in the lowlands. So near yet so far it would seem.............

[Paul-Michael]

Met Office seems to mention thunder again for the NE which was absent from yesterdays forecast:


Headline:
Rain clearing, but still a few sharp showers to come.


Today:
A cloudy morning with further rain at times, some of which again could be heavy. The rain should clear by midday with a brighter afternoon and a few sharp showers. Maximum temperature 24 °C.


Tonight:
A muggy night to come. Any heavy, locally thundery, showers slowly clearing during the evening, then some clear spells overnight. Minimum temperature 14 °C.


Wednesday:
Another hot and humid day, again with the risk of some scattered heavy, thundery showers developing. Maximum temperature 26 °C.

Updated: 0343 on Tue 2 Aug 2011