Convective / Storm Risk Discussion - 21st July 2013 onwards

[Tom Jarvis]

Upper ridging persists across Central Europe and the North Sea, while an upper trough slowly approaches from the Atlantic. On the forward side, advection of high WBPT plume northwards across the British Isles will occur, destabilising in response from either various shortwave troughs or diurnal heating (or both). Several bouts of thunderstorm activity is possible during this forecast period.

Discussion:... CS + SW ENGLAND, SE WALES, S MIDLANDS ...

Ongoing thunderstorms currently over northern France this evening, associated with a shortwave trough, will continue to drift northwards across the English Channel overnight and through the early morning hours, becoming increasingly elevated. Further elevated development is possible ahead and behind this cluster of thunderstorms as the moisture plume destabilises. Therefore, elevated thunderstorms are expected across parts of Hampshire, Dorset, Isle of Wight during the early hours, migrating further north across the West Country and possibly SE Wales/S Midlands/Home Counties towards and after dawn. Slow-moving storms with PWAT >30mm could cause some local flooding, and given degree of instability (MLCAPE up to 1,500 J/kg) some hail up to 1.5cm in diameter is possible in any stronger cores, particularly in Dorset/Hampshire/IoW, before the storms weaken in intensity and coverage during Monday morning.

... MIDLANDS, N WALES, EAST ANGLIA, HOME COUNTIES ...

There is likely to be various amounts of cloud debris from decaying overnight elevated convection drifting slowly northwards, which may inhibit strong insolation at times. Nonetheless, low-level wind convergence and high surface temperatures/dewpoints (30C/19C being a conservative range respectively) coupled with the progress of an upper trough is likely to result in scattered surface-based thunderstorms during the afternoon and evening hours, becoming more widespread with time. CAPE >2,500 J/kg will result in some very electrically active thunderstorms, with hail up to 3.0cm in diameter possible. Shear is rather weak, so cell organisation is likely to be limited at times, but backed surface winds with slight directional shear may allow a funnel or weak tornado to form briefly. Again, slow-moving downpours and PWAT in the high 30's mm locally could result in local flooding given dry ground currently present. Given hail and rainfall thresholds, this is borderline SVR and may require an upgrade during Monday if development continues to look likely (dependent on cloud clearance etc).

... NW ENGLAND, SW SCOTLAND, YORKSHIRE, NE ENGLAND ...

Gradual upscale growth of scattered thunderstorms is expected during Monday evening as destabilisation continues to occur along the moisture plume axis. Therefore scattered thunderstorms are likely to form over these areas through Monday evening and night, the development extending progressively further northwestwards across the SLGT and perhaps ISOL areas. Heavy downpours may result with some localised flooding, with some hail also possible in any stronger cores.

... W/NW IRELAND, W NORTHERN IRELAND ...

Scattered showers and a few thunderstorms are expected to develop during the afternoon and evening hours in response to diurnal heating and the development of a low pressure centre over the Atlantic just north of Connaught. Hail up to 1.0cm in diameter is possible, with storms gradually moving offshore to the

AND FOR THE SOUTH EAST

ZILCH LOL

http://ukasf.co.uk/storm-forecasts/256

[PeterDoswell]

Looking with an untrained eye at radar over the last hour Storms to make landfall in Southampton Portsmouth area in next 2 - 3 hours . Pressure 1014mb in Southampton and unstable . Definately heading NE across the channel . Lets hope for a big breakdown  

[NO LONGER POSTING]

come on storms!!! lets make everybody happy!!

[NO LONGER POSTING]

Dont know about anybody else but I am sweating buckets!

Edited July 21, 2013 by Surrey

[Willsy]

the storms are here. theres an epic cumulonimbus jusd sw of me in poole. theres flashes every 3 secs atleast

[Allseasons-Si]

The old MCS has died but  it looks like a new one is forming to the NW of it

Edited July 21, 2013 by allseasons-si

[NO LONGER POSTING]

http://www.flightradar24.com/51.35,-0.73/7

 

 

Planes playing dodge the storms..

[DAVID SNOW]

The old MCS has died but  it looks like a new one is forming to the NW of

Bombay?

[poseidon]

[paul m]

Dont know about anybody else but I am sweating buckets!

Painful....

[NO LONGER POSTING]

Painful....

 

Dont even go there with pain... 

[Wet'n'Dry]

In my opinion everyone is hoping for imports to arrive from France but in reality I feel the storms will be fuelled by the moist air approaching from the west. Some may see a few strikes off our southern coast but that's not to be relied upon to make a storm of any note!

The last few days have seen humidity levels down at the 30% region, only today have they risen to 60% but despite that we have had little moisture to allow convection.

I'm no expert but my gut feeling tells me to look to the west, as without fuel the storms are not going to happen!

[paul m]

Anyone with a decent live webcam on the south coast care to share as the Poole one really peeing me off now

[Petorious]

Glad to see these storms making it across, as it did look a bit hit and miss to start with, hopefully they will build up over the land taking in the extra humidity and feed up to my location for early hours of the morning as  I look to be in their path (very very south midlands)

[Lazz]

Anyone else a bit surprised that estofex hasn't issued any warnings?

[ZONE 51]

Recent image:

[Allseasons-Si]

Anyone with a decent live webcam on the south coast care to share as the Poole one really peeing me off now

Just as good as dead if you ask me,now who gave us this link lol.

 

on a serious note,surely there could be some better stat cams out there,anyone

[ZONE 51]

Anyone else a bit surprised that estofex hasn't issued any warnings?

I've been to busy..

Edited July 21, 2013 by ElectricSnowStorm

[JK1]

Probably won't get any thunderstorms in my area expecting to miss out again

Edited July 21, 2013 by JK1

[Moleyroley]

I'm on Portland , and currently watching a light show from my roof terrace ! Love it

[viking_smb]

is there much thunder?

[Costa Del Fal]

Good chance if this hitting here tonight. And with tomorrow evening and Tuesday morning at chance here, I'd say this area has one if the best multiple chances!!!

[Moleyroley]

A few rumbles , more lightening than anything , and one heavy downpour

[Supacell]

Not sure how far north the elevated storms are likely to get tonight. Certainly counties such as Dorset, Hampshire, Wiltshire, Gloucestershire and surrounding have a good chance though.

[Wilxy]

Hopefully they wont die out as they move more inland.