Stormy Wednesday 15th August 2012

[AWD]

being a non technical person on here, but trying to learn, can anyone offer an opinion what weather we COULD experience in hampshire, south coast area tomorrow? thanks in advance

In brief:

Wet & Windy morning with heavy, possibly thundery rain.

Drying up into the afternoon with sunny intervals but remaining very windy.

[lfcdude]

Ian Fergusson on BBC Points West spoke of the heavy rain moving North with thundery element possible in the East of the region (Wiltshire/Dorset)

so what that means for parts further East I'm not sure.

What has surprised me is how there seems likely to be (in this region) a very wet period between around 07.00-13.00 and then almost a complete

clearance to a sunny afternoon/evening.

Sounds good... think il get up nice and early to walk the dogs to avoide the rain/Hopefully Thunder...

[smoggyjester]

In brief:

Wet & Windy morning with heavy, possibly thundery rain.

Drying up into the afternoon with sunny intervals but remaining very windy.

thanks much appreciated

[Stuart]

Synopsis:

A deepening area of low pressure approaches from the Atlantic. Ahead of the cold front, strong WAA will allow a plume of significantly high ThetaE to advect northwestwards across the British Isles. There is potential for severe convection ahead/along the cold front.

Discussion:A strengthening jet will move northwards across southern Britain, driving an active frontal boundary northwards as a surface low deepens to the southwest of Ireland. Within the warm sector, a substantial plume of very high ThetaE is expected, which should destabilise with the approach of the cold front.

As is often the case with frontal destabilisation in plume events, there is some uncertainty as to how widespread such convection will be. General thinking is along the cold front, with 40kts DLS and 30kts LLS, LEWP/bowing segments may form, with locally torrential rain and occasional lightning. With such shear values and substantial backing of surface winds, bowing segments would also be capable of produce a weak to moderate tornado.

If there is any sufficient insolation within the warm sector, it is possible that isolated convection may form ahead of the main cold front. If this is the case, then such convection may benefit from 700-800J/kg CAPE, coupled with ample shear and helicity with backed surface winds, and possibly resulting in a supercell capable of producing moderate hail and a tornado. However, this scenario is heavily dependent on sufficient cloud clearance, which is questionable.

Also, there are indications in most models of the eastern portion of the cold front becoming a zone of broken convection (mainly East Anglia and South East England), which would benefit better from ample shear and helicity to intensify into scattered thunderstorms or supercells, with a heightened risk of hail and a tornado. PWAT values of >40mm would be more than capable of producing local flooding from cell backbuilding.

http://www.ukasf.co.uk/storm-forecasts/206

[Captain Shortwave]

It looked until the regional forecast that the area i live in was going to experience only a little rain, but that forecast has brightened my hope of some proper good thunderstorms. But can only help but think that living by the sea (Great Yarmouth) will probably scupper that chance, with the winds from the South East.

[smoggyjester]

what time are things expected to kick off around the south does anyone know?

Edited August 14, 2012 by smoggyjester

[Hathers]

Looking at the Ukasf storm forecast, I don't think I've ever seen such a large part of the country under a severe red warning before.

[smoggyjester]

Looking at the Ukasf storm forecast, I don't think I've ever seen such a large part of the country under a severe red warning before.

do you have a link please?

[Supacell]

I cannot see the ukasf map. Is West Yorkshire under the severe area anyone?

[CHOCOBLUE]

Yes villaman,but bugger all from the met.!

[Hathers]

http://www.ukasf.co.uk/storm-forecasts/206

I'm on my phone so can't post the map

[smoggyjester]

thanks im not in red lol

[Hathers]

I don't know how reliable Ukasf are with there storms forecasts though. I was under moderate on Sunday but saw nothing.

I'm looking forward to Estofexs update. Wouldn't a level 2 be nice.

[Paul Sherman]

Agree with Nick F, The parameters are there for a re-run of 28th June 2012 if things fall into place, a lot can still go wrong if for instance an MCS Forms instead of a possible broken line of Severe Thunderstorms along the Cold Front. With South East winds and 40kts of Deep Layer Shear and with temps/dews spreads of 75/68 there could once again be some very large hail along with a few Tornadoes tomorrow mainly from Central Southern England up into the Midlands and East Anglia and dare i say it Lincolnshire again!

Have the kids so cannot chase but will be on the look out locally in SE Essex although i feel this will NOT Benefit like always in these set-ups, good luck to all venturing out

Paul S

[Weather Wizard]

I am flying tommorow from Luton should be a bumpy flight

[paul m]

I cannot see the ukasf map. Is West Yorkshire under the severe area anyone?

Looks like we are but what do you think of our chances up here

[AWD]

The threat is looking increasingly likely to be further NE from me tomorrow now. Working so can't get in amongst the action either.

Nice though that there is support for this event from professional bodies now though.

[Supacell]

Agree with Nick F, The parameters are there for a re-run of 28th June 2012 if things fall into place, a lot can still go wrong if for instance an MCS Forms instead of a possible broken line of Severe Thunderstorms along the Cold Front. With South East winds and 40kts of Deep Layer Shear and with temps/dews spreads of 75/68 there could once again be some very large hail along with a few Tornadoes tomorrow mainly from Central Southern England up into the Midlands and East Anglia and dare i say it Lincolnshire again!

Met Monkey seem to think that it will be Midlands up into Yorkshire the main risk area, which would make me very happy. To be honest though, expecting to win a fight over who gets a storm between West Yorkshire and Lincolnshire is a bit like putting Boris Johnson in a fight with David Haye lol!

So... if i can get out of work early i may head down into Lincolnshire for a re-run of the 28th June

Paul M, i think our best chance could be if the CF becomes broken and a line of severe storms can develop as mentioned in Paul Sherman's post above. However, we may just be too far northwest to benefit. Although it would only take the slightest of changes to put us in with a good chance. Would take something though to pull those storms away from the Lincolnshire hoover towards our region!

Edited August 14, 2012 by Supacell

[Cloud 10]

Storm taking shape nicely on latest sat.

[Eskimo]

In the middle of that red warning, sweet!

[A.J]

My mum's recently moved to Sleaford, lincolnshire to enjoy her retirement...Maybe I'll visit her tomorrow...lol

I can envisage the conservation...

"Son, how lovely to see you...Aw, have you brought the grandchildren with you?"

Me: "Grandchildren?....Nah, I've come here for supercells, tornadoes, & very large hail!!"

[Staffordshire]

I am flying tommorow from Luton should be a bumpy flight

i flew back to east midlands today, twas very bumpy indeed and we had 80+mph tail winds on the way back so if its similar you may have a longer than planned flight!

[Chris W]

I hope we get a good show (a moderate UKASF warning so nearly coming off on Monday for me, now a red one covering work and home) but that it moves quickly enough and hits the right areas to avoid serious damage - I would dearly love a good storm but will forego it at the drop of a hat for others to remain safe.

I notice that although the Met Office warning is yellow their precipitation forecast all day today for tomorrow has shown very intense bands eithin the main band through the morning and into the afternoon. I expect an amber warning to come into force for the south west through the midlands sooner rather than later, as far as I see the Met forecasting this event.

Edited August 14, 2012 by Chris W

[Robbie Garrett]

I don't want to annoy anyone by any magnitude, but I am in line with the MetOffice with this one.

http://www.metoffice.gov.uk/public/weather/warnings/

Cannot for the love of life see why a Severe has been issued, http://www.ukasf.co.uk/storm-forecasts/206 Fair this is lots of potential, but can't see what warrants this risk when according to the latest radar runs where the MetOffice warnings are out, is where the activity will be.

Unless this is another MetOffice cock up, a lot of Airlines are not going to be happy come tomorrow afternoon as the TAF is not indicative of anything severe. Looks like an Average British Weather day across most Southern Airports.

[Hathers]

can someone explain to me why the Met office don't seem onboard for Thunderstorms to develop? Ukasf, Met monkey, Net weather all seem convinced storms will break out.