3rd Aug 2011 - Storm/convective Forecast Discusion And Reports

[Jane Louise]

Another stormy day betides although nothing in store for me again. But good luck to everyone else.

[Aaron]

Tomorrow might be better for me. Hopefully the wind will switch to a more southerly/south easterly direction, when we do best for our storms. Here's hoping

[JamieUK]

Oh wowwwww. The storm here is torrential! The wind has picked up. It's fierce out there! Thunder and lightning. THE LOT!

[Jane Louise]

Oh wowwwww. The storm here is torrential! The wind has picked up. It's fierce out there! Thunder and lightning. THE LOT!

Shouldn't that be posted in the other thread? I'm even more jealous now.

[Costa Del Fal]

Although I have have little faith in the Met Offices weather symbols, the updated Invent is correlating into some interesting symbols which is a load of Hail across the area here in the morning. I for one minute think this is extremely unlikely. Hail is such a fine margin and I dont know why they bother having a symbol for it in my opinion??? Then by the evening there is Thunderstorms/Thundery showers over the region.

I highly suspect the next update will shunt things East.... this thought based on the West's rotten luck lately and how other models are having none of this.

[VillagePlank]

[London/Kent/ESussex]

Here's the skew-T, London-Heathrow, 15z tomorrow.

Convection will be initiated by surface heating quite early on probably sometime between 9z and 12z although it's on the margin with surface Theta-W at 22C (the initiation temperature) Showers that form have around 69% chance of becoming thunderstorms.

My view is that GFS is under doing the temperature. This run looks suspect - and CAPE >1000j/kgs? Well, we've seen that before on the charts haven't we?

Edited August 2, 2011 by Sparticle

[Static Prevails]

I'm really not sure about tomorrow. Obviously, it seems like things will be further south and east, but maybe I'll nick something...

If not, I'll just go on Red Dead Redemption and catch some virtual storms. Even they've been evading me lately though. :lol:

[Jane Louise]

I have Mackeral sky here with Ac Cas.... hopefully a good omen for tomorrows potential. 7am I think a shower is due here according to the Met office invent.

[NUT]

Not sure about tomorrow here but thursday admittedly so far according to the zentrale GFS cape+lifted thingy is looking pretty good for most of Scotland and east england

Edited August 2, 2011 by NUT

[Staffordshire]

Can someon. Post a link to meto invent please?

[80sWeather]

Very muggy now after earlier shower,gone very dark again and heavy rain just started.God i love this type of weather

[Jane Louise]

Can someon. Post a link to meto invent please?

Here you go Staffordshire.

http://www.metoffice.gov.uk/public/pws/invent/weathermap/

[Phelpsy]

seen nice large glaciated cloud top earlier with beautiful pileous on top. Then started forming into what looked like an anvil. Must have been a line on way to Aylsebury? Anyway still muggy and also have mackerel sky and AC cast to Jane. here's hoping lol

[Raidan]

Mackrel sky here to.

[Stuart]

Last Updated: 20:02 Tuesday, 2nd August 2011

Valid: 00:00 Wednesday, 3rd August 2011 - 23:59 Wednesday, 3rd August 2011

Areas Affected:

Central and Eastern England

Synopsis:

A marked upper trough is evident to the west of the U.K. and this is supporting cyclonic activity at surface levels as low pressure and frontal systems move into parts of Ireland and South-west England during the day. Ahead of this a very warm and humid air mass is forecast to persist and it is within this air mass that convective activity is greatest.

Discussion:

The progression towards cooler and fresher conditions is forecast to take place tomorrow, but prior to this there is a significant threat of convective activity and thunderstorms across Central and Eastern areas of England in particular. The UKMO MESO, NAE, WRF and NMM models are all signalling some well broken cloud during the course of Wednesday morning which will lead to a significant amount of solar input and surface heating.

Forecast soundings across parts of the East Midlands and down towards South-east England (eg Nottingham to Cambridge) are showing that a completely unstable atmosphere is expected with surface temperatures near 25C and dew points near to 16C, but with a few degrees variation possible. Given that predicted Tmax temperatures between 25C and 29C are expected generally within the High Risk area, then these surface conditions are forecast to be achieved. A high plume of theta-w air (14C to 16C) exists across parts of Central and Eastern England through tomorrow and it is within this zone of high theta-w that the greatest threat of convection exists. Also, despite some model divergence there also seems to be the potential for a marked convergence zone developing from the Greater London region northwards up to the Wash area during the course of the afternoon.

SBCAPE values in excess of 800j/kg are forecast, but a more modest 300 to 500j/kg of MLCAPE is evident. What is significant however is the depth of instability that may well be available when convection occurs. Forecast soundings are signalling instability up to 30 to 35,000ft which is a large portion of the atmosphere. The primary driving force will be the heat, humidity and potential convergence zones as there is little or no LLS or DLS shear with both values less than 15 or 20KT. As a result more single celled storms are expected, but where these do develop given such deep instability then there is a threat of some localised flooding from torrential, localised downpours, hail and gusty winds, particularly as any cells/storms reach maturity. The convergence zone may well aid to bring a threat of funnel clouds, but rather high LCL levels, a lack of shear and helicity are likely to signal little or no risk of any funnel or tornado activity overall.

http://www.ukasf.co.uk/storm-forecasts/60

[Staffordshire]

Here you go Staffordshire.

http://www.metoffice.gov.uk/public/pws/invent/weathermap/

Dosent look to bad aii? Are they generally correct or just rubbish?

[Jane Louise]

From UKWeatherworld for tomorrow.

Sorry I can't post the risk map up.

8.30pm Tues

Slight Risk of Isolated Thunderstorm 15Z-21Z Central East regions as per map

Some uncertainties here regarding moisture mixing out up and over the potentially high surface temps!!

Atlantic low makes slow progress toward the east ( positioned Ireland) maintaining a fairly sustained surface flow from Biscay. Forecast temps could well reach 27 deg or more across central eastern region by early afternoon. This will likely have the net effect of broadening the gap between the available dew surface points. Resulting in at best, elevated cloud bases and at worst complete mixing out of moisture! Similar scenarios have delayed convective initiation to as late as 6pm on occasions. Conversely prime supporting factor here will be moisture convergence, the absence of which would make this convective discussion pretty much pointless.

Once again rather weak upper support and only marginal lifting influence from mid level PVA. Strongest lapse rates remain near surface though there is some moderate influence for potential instability from the west late in the period. All in all not a day to lay any bets for any outcome hence 'Slight' risk is more appropriate.

If surface convergence is able to trigger a storm then this is likely to become quite intense for a time in the form of a cluster with the risk of moderate sized hail and intense CG's!

http://www.ukweatherworld.co.uk/forum/forums/thread-view.asp?tid=44242#M643965

[Costa Del Fal]

Tony from UKWW keeping things only for the East tomorrow but UKASF bringing the threat to more Central areas also. I think UKASF are closer to the mark so far especially given the more varied models this evening and gives scope for further potential changes.

[Aaron]

Tony from UKWW keeping things only for the East tomorrow but UKASF bringing the threat to more Central areas also. I think UKASF are closer to the mark so far especially given the more varied models this evening and gives scope for further potential changes.

UKASF storm forecast looking very good for all central and eastern areas of England, even some Pennine areas and west of the Pennines are in the main risk area. It'll probably change more tomorrow though.

[Static Prevails]

UKASF is pretty good for tomorrow, with some definite potential around most central areas. It's nice to see I'm in the orange risk zone too! This is slightly unrelated, but I also like the fact it may be sunnier tomorrow; that'll bring higher temperatures and the sun and heat will only aid convection.

Also, by the way, which direction will the storms be moving in tomorrow?

Edited August 2, 2011 by IAmJohnnyDisco

[Cheshire Freeze]

Tony from UKWW keeping things only for the East tomorrow but UKASF bringing the threat to more Central areas also. I think UKASF are closer to the mark so far especially given the more varied models this evening and gives scope for further potential changes.

lol the western extent of the 'main risk zone' is 15 miles to the east of here over Stoke on Trent Baaaaahhhh humbug

[Polar Bear]

Ok so as i understand it tomorrow we as in Newbury won't see much of the storms and the potential is further west. I only have iPhone here which isn't helping look into things abit more. The question is though I am looking forward to watching things develop however I am also intending to ride the horse tomorrow morning in wide open countryside. Realistically is there s potential out there of instability which should make me reconsider and just spend my time watching things develop instead?

[Harry]

My thoughts for what they're worth

Edited August 2, 2011 by Harry

[Static Prevails]

lol the western extent of the 'main risk zone' is 15 miles to the east of here over Stoke on Trent Baaaaahhhh humbug

I had that today from UKASF. It's annoying, isn't it? :lol:

It didn't make a difference though, nothing has happened today bar the odd thundery shower in Central Southern England.

My thoughts for what they're worth

It's nice to see you've included your area in the main risk zone.

No, but joking aside, I'd agree with that! Tomorrow will hopefully be much, much better than today.

[Cheshire Freeze]

I had that today from UKASF. It's annoying, isn't it? :lol:

It didn't make a difference though, nothing has happened today bar the odd thundery shower in Central Southern England.

If it does make a difference and Stoke gets a thunderstorm I shall not be impressed though I shoudn't be surprised it's happened before!

Even if there was a solid wall of thunderstorm approaching which was 40 miles long and 10 miles wide, we'd still go through the gap with the weakest precip lol