Uk Convective General Discussion & Forecasts, 7th July 2012>

[Robbie Garrett]

Just had lightning and thunder here in SE17.... wohoo!! Storm Number 12!! 2nd overnight storm of the year.

[andymcpool]

Slight rumble in Battersea

[Robbie Garrett]

Slight rumble in Battersea

Definitely can confirm, must be from nocturnal cooling. Would be a rather good MCS if there was some oompth in it if it was a MCS, quite amazing how this cell fired up briefly right over South London, within this band of heavy rain.

Interesting to see what the rest of this band can produce.

Edited July 7, 2012 by Robbie Garrett

[Robbie Garrett]

Gatwick Confirmed Thunderstorm, heading this way....

EGKK 072350Z 04005KT 5000 TSRA SCT003 SCT006 BKN010CB 14/14 Q1004

[Dean E]

Clearly something has set this off. Northern France has recently gone boom too, especially over Paris. Connected maybe?

[Tim B]

Gimme gimme gimme a storm after midnight, oh some static help me keep the boredom at bay!

Sorry, couldn't resist!

Looked good at first but oh well.

[Darren Bown]

http://ukasf.co.uk/storm-forecasts/192 a general storm forecast from ukasf for much of England and wales except east of Pennines and southern coastal counties ( is this Manchester/bolton's turn?!) day off today playing games and storm radar watching.

[knocker]

UK storm risk 1500.

[Norfolk Sheep]

Just rain here overnight as per usual. Still, cleans the patio nicely I suppose!

[Nick F]

Might have the best chance of the last 7 days of hearing thunder today, though not holding my breath, still not heard thunder since I came back from storm chasing on the 12th June.

Storm forecast for today: http://www.netweathe...0c901ac33106e3c

Valid: 08/07/2012 09:00 - 09/07/2012 06:00

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

Synopsis

Upper low overspreads England during the forecast period, surface low situated across SE England at 07z Sun will drift NE over the S North Sea by 18z.

... E WALES, MIDLANDS, S/SE ENGLAND AND E ANGLIA ...

Subject to cloud cover from morning showers, diurnal heating in cloud breaks of a moist boundary layer here (DPs 14-15C) beneath mid-upper low/cold pool will likely yield 300-600 j/kg SBCAPE. Although heavy showers are ongoing, insolation will generate sufficient cloud height for scattered thunderstorms to develop late morning and through the afternoon/early evening. Vertical shear and upper winds will again be rather weak, so an organised threat of severe weather is unlikely, though a few wind convergence zones will likely focus showers/storms and with light winds aloft, slow-moving downpours may lead to some localised flash flooding. Storms may also be accompanied by hail, gusty winds and also there is a chance of funnels or even brief weak tornadoes/waterspouts where wind convergence helps more buoyant updrafts to rotate. Storms should fade later this evening as diurnal heating wanes.

Issued by: Nick F - Forecaster for Netweather

[Coast]

So apart from the rain, what's in store for today?

Well no forecast from ESTOFEX but I'm not sure that means no storms? UKASF forecast:

Forecaster: Chris

Last Updated: 2012-07-07 22:15:00

Valid: 2012-07-08 00:00:00 - 2012-07-08 23:59:00

Areas Affected:

Wales, Central England.

Synopsis:

An upper low vortex will continue to spin across Britain bringing generally unsettled conditions to most places. At the surface the low will be centred just to the east of Norfolk in the North Sea with generally a N to NW flow aloft across southern Britain.

Discussion:

Low confidence of lightning, however, most models indicate somewhere between 300-600j/kg of CAPE through the middle part of the day, however the Spainish HiRLAM, shows very limited CAPE values, most likely due to it's handling of cloud cover through the day. The NAE suggest that any early low cloud and rain should clear across the SLGT risk area allowing for enough sunshine to produce some sharp showers. If these develop a few of them may turn thundery from late morning through mid-afternoon. Very little shear is forecast across the risk area, therefore most showers will be of the short-lived pulse variety. However, given the risk of some surface convergence with the close proximity of the surface low + insolation around midday, low level CAPE could be enough to help support an isolated funnel from the early stages of a developing shower.

Nothing from TORRO or SkyWarn so here's the charts:

Aviation charts have that area further North:

So do GFS:

Even more rain in the very SE corner!

SBCAPE:

Lapse rates in East Anglia:

HiRLAM confines it to the very East, a Kent Clipper+ ????

In simple terms:

An interesting one to keep an eye on if you're not watching tennis or the British GP over a roast dinner!!!

[Supacell]

I don't think it is my turn today.

Best areas will be as below I think (in black box). I have marked on where the convergence zones and higher CAPE overly each other in red, which could be focal point for storms.

Just seen Coast's charts. Look at the lightning risk chart for East Anglia at 12 noon today!!!

Edited July 8, 2012 by Supacell

[Coast]

I'm sure I heard something around 5.00am this morning, but nothing on any detectors. Fingers crossed for today though

[Cloudwatcher]

I don't think it is my turn today.

Best areas will be as below I think (in black box). I have marked on where the convergence zones and higher CAPE overly each other in red, which could be focal point for storms.

Just seen Coast's charts. Look at the lightning risk chart for East Anglia at 12 noon today!!!

We are at the top left of that risk zone but near the convergence line, Wonder if today will be our day....!

[Supacell]

Question for the experts here

With most of us being in a NW flow today, could this mean showers and storms would develop and filter through the Cheshire gap one after the other as per showers that occur in winter?

[Hurricane Debby]

Torrential rain here at the moment and pretty much throughout the night as well. And pleased to say I heard my first, singular rumble of thunder last night !!

[Nick F]

The grey skies and torrential rain here on and off since 4.30am - doesn't bode too well for storms today. Oh well.

[Robbie Garrett]

Nothing much interesting on the MetOffice radar till 1600, with some big blobs passing through.

Last night was mostly just heavy rain, I guess I was lucky to get an isolated TS. Brightening up now a tad...

[Cloudwatcher]

Question for the experts here

With most of us being in a NW flow today, could this mean showers and storms would develop and filter through the Cheshire gap one after the other as per showers that occur in winter?

I'm interested in the response to this too!

[Darren Bown]

Question for the experts here

With most of us being in a NW flow today, could this mean showers and storms would develop and filter through the Cheshire gap one after the other as per showers that occur in winter?

Clouds here are still moving from a more east to west pattern still like yesterday.

[Methuselah]

I'm interested in the response to this too!

I think it depends on the upper winds, too; unfortunately, it's too cloudy to see much of what's going-on up there!

[Thundery wintry showers]

Not looking good for convection here in North Yorkshire, or for that matter sunshine or warmth, with a thick sheet of stratocumulus overhead. I remarked in the "advantages of the wet summer" thread that I'm not against wet summers if they are frequently characterised by thundery downpours with sunshine in between, but during this summer such conditions have mostly been scuppered by large amounts of cloud.

[Chris.R]

I would like to know if i'm out of the picture because of the NW wind. This means that the wind is from the sea, but not as directly as if it was from the west. I'm trying not to think that we'll breed the showers and they'll only develop into storms as they track SE. PS, I would think the chesher gap effect would happen yes.

[Cloudwatcher]

I would like to know if i'm out of the picture because of the NW wind. This means that the wind is from the sea, but not as directly as if it was from the west. I'm trying not to think that we'll breed the showers and they'll only develop into storms as they track SE. PS, I would think the chesher gap effect would happen yes.

Can only go on what I'm seeing overhead but from my location the wind is blowing from NW to SE, in the direction of Chester. Some good heat out there today in the sunshine too.

[Chris.R]

But I'm a mile away from the coast and there is not much land apart from Formby point to the NorthWest of me. I'm just hoping the sea isn't too cold to sustain convection.