16th Sept - 18th Sept 2011 Storm/convective Forecast Discussion And Reports

[lewisosd]

So what exactly are we expecting tomorrow? Elevated storms? Pulse type? Isolated? Hope everyone is enjoying the nice weather we have been having recently!

[staplehurst]

So what exactly are we expecting tomorrow? Elevated storms? Pulse type? Isolated? Hope everyone is enjoying the nice weather we have been having recently!

Pulse type in a classic rPm airmass

[Costa Del Fal]

Much of the country at risk tomorrow. Cape not to get excited about but good enough and some of the best Lapse (28-30 over some central areas especially) rates on offer for some time.

Some very low Equilibrium Levels tomorrow also with as low as -50c for a time with -30 to -40c for much of the day for many which could allow some good lightning.

Edited September 16, 2011 by Blizzards

[lewisosd]

Sorry to sound a bit dense but what does rpm airmass mean?

[Bluebreezer54]

^^ Returning Polar Maritime I believe

[LeeKay]

Looking forward to tomorrow, for one a day off work and second, September storms!

GFS view so far 12z: & 18z

Strange i didnt hear any thunder thismorning as i was up at 0600 and lighting was recoreded on ADT up until 0800 just north east of home.. dam!

Anyway, round 2 tomorrow

[Jane Louise]

Ok,

Here's tomorrows forecast from UKASF. I'm in the severe area but I doubt anything at all will happen for me lol.

Can't seem to post the map up so best to click on the link.

Good luck and look forward to seeing reports and pics if anybody does get anything lol .

http://ukasf.co.uk/storm-forecasts/107

Areas Affected:

SVR: SE Wales, W Country, S + W Midlands

MDT: Northern Ireland, E Ireland, S + SE Scotland, NE + E England, S Wales, W Country

SLGT: Whole of the United Kingdom

Synopsis:

Upper trough becomes a cut-off upper low with a cold core. Cold mid-levels atop daytime heating will result in widespread convection across most parts of the United Kingdom on Saturday.

Discussion:

Cold mid-levels will overspread the country during the day, with T500s as low as -27C locally. With daytime heating, lapse rates, already reasonably steep over seas due to high SSTs, will steepen across inland environs, resulting in over 600 J/kg CAPE. Widespread showers and thunderstorms are expected, with two main areas of greatest lightning coverage (MDT areas). ELT's as low as -45C will also aid widespread lightning coverage, whilst such cold air aloft will allow hail to fall in many of the showers.

Northern Ireland, S + SE Scotland, NE + E England will be under the main centre of the low, and thus winds will be lighter allowing cells to mature and benefit from better conditions for widespread lightning coverage. Meagre DLS limits the severe potential.

Across S Wales and the W Country, stronger winds may inhibit cell growth due to shearing of anvils etc but it is likely under the trough axis and the coldest mid-levels that coverage could still be widespread enough to warrant a MDT level.

Under the SVR threat level regions, an overlap of typically ~40kts DLS and >20kts LLS significantly increases the potential for a tornado to develop. Equally, given the cold air aloft and cold cloud top temperatures, hail >2cm in diameter is quite possible, and thus both instances meet our criteria for a SVR threat level.

Showers and thunderstorms will continue well into the evening and overnight, but becoming increasingly confined to coastal areas where the highest surface temperatures remain (as a result of high SSTs vs cooler land surface temperatures).

[Costa Del Fal]

Looking forward to tomorrow with some of the best ingredients of the 2011 storm season and a risk exisitng almost all day from early hours until well into the evening.

Would love one last night display. Had about 3 this year of them.

Edited September 16, 2011 by Blizzards

[Aaron]

Doesn't look all too interesting for my area. But I've already had an amazing storm today so I cannot really complain!

Edited September 16, 2011 by Aaron

[Chris K]

First time ive seen myself under severe from UKASF...

[Purplepixii]

Apparently I have a 56% chance of storms around 22:00 tomorrow but I wont hold my breath - it's been a poopy year for sferics here this year!

[ZONE 51]

Widespread downpours and thunderstorms-can we get excited!!

heres the cold upper air at 500hpa, surface temps,wind-GFS for afternoon, and NAE ppn for saturday, have put some lightning on the last 2 indicating storms continuing well into late eve/overnight for some!

the first 2 i dont need to mark on as we know the storms are building up on saturday afternoon, because some may think after dark all fades a way, it does usually ,but not in this situation, so any storms staying around especially to late and giving some fantastic displays for some!

here is the radar at 135am BST if anyone wants to see whats about now but dont have access to rad, the lines of showers out West England and Wales im expecting to develop and move into and across Southern England soon,

-surface wind-generally windy or gusty for some areas

-anvil spotting/hail!

-warm in SE/EA especially at 17c/18c-even 15c if the sunshine is out it feels warm, but in downpours or storms feeling quite cold, up mountains and hills would get cold-take coat in case!

Edited September 17, 2011 by ElectricSnowStorm

[Liam Ellis]

Thunderstorm has popped up here in NW Wales - nothing big but It's something.....

[ZONE 51]

Thunderstorm has popped up here in NW Wales - nothing big but It's something.....

already! now thats a start to the day! think today is one of the best this season to come, the elements are there for some mega lightning displays, and i dont think even Se Englands going to get nothing as usually nothing turns up here! Edited September 17, 2011 by ElectricSnowStorm

[Chris.R]

Hoping for something interesting later today, have already had some moderate showers and am having quite a heavy shower ATM.

[Nick F]

Good morning storm fanatics, should be quite an active day hopefully, already some storms rumbling away across NW England (Lancs, Sern Cumbria). My forecast for today:

Convective / Storm forecast - Issued 17/09/2011 07:00

Forecast Summary Map

Click for full size

Valid: 17/09/2011 06:00 - 18/09/2011 06:00

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

Synopsis

Upper low sits sits above the UK during Saturday, with a surface low centred over Nern Scotland at 12z with troughs/wrap around occlusions rotating around the centre.

… UK and EIRE …

Readily unstable rPm airmass across the UK today, characterised by steep lapse rates beneath cold pool of upper low, will see an active day of convection across much of the UK. Thunderstorms have already been affecting NW England this morning along an occluded front moving east and we should see increased thundestorm activity later this morning and through the afternoon. A trough is expected to enter from the west across Wales and SW England by noon then continuing E and SE - which will increase activity and also surface heating will allow scattered heavy showers and thunderstorms to develop more widely elsewhere across the UK. Vertical shear will be rather weak, as winds will be blowing the same direction at all levels and the strong jet will be sliding away from southern England, so no severe weather is anticipated. Any storms may be accompanied by hail, gusty winds and torrential rain with risk of localised flooding. Low LCLs towards the west, buoyant updrafts over now warm SSTs and local topography may allow funnels or even a brief weak tornado to form across coastal SW England and Wales. A few storms may continue around southern and western coasts overnight, given warm SSTs and cold air aloft.

[georgiedre]

i too was woken up by a thunderstorm at about 4ish i think.. very heavy rain and about 6 lightning strikes .. the wind really picked up during it too! we have been lucky for storms here this year!!

[The watcher]

Greetings from Austria everyone. Still on my eurotrip. Hope some of you get the storms forecast. I'm excited for tomorrows level 2 issued for where iam at the minute. already had 1 nighttime storm in Calais on the 3rd September. Good luck all.

[Chris.R]

No thunder here and no sferics apparent either though there was a few near by earlier.

[DeepSnow]

It is looking good for today! Hope to get some good storms! http://ukasf.co.uk/storm-forecasts/107

Edited September 17, 2011 by DeepSnow

[Jane Louise]

Good luck everybody It really looks promising today, maybe the best potential of the year so far.

[Guest Quantumsnow]

Good luck everybody It really looks promising today, maybe the best potential of the year so far.

That's what I like to hear! Been so dead round these parts this year, well for quite a few years now. Come on storms do your best!

Good luck all

[Lynxus]

It is looking good for today! Hope to get some good storms! http://ukasf.co.uk/storm-forecasts/107

LOLOLOLOLOLOLOL ......... x10^10000

U mad?

Is that a red area with me / jane / tricky / dogs etc all in it?

naaa

Your mad.

Im gonna have to do some research today. .

Dont believe ya.

[SteveB]

Not as many showers as the Beeb were predicting last night. Expected to be woken up in the early hours by a rash of showers, but instead just had the one about an hour ago which was blustery and heavy.

Hoping for much more today, but fear its not going to live up to expectations.

[Lynxus]

Right then..

Camera on charge : ☑

Beer : ☑

New radar subscription : ☑

Storms: ☒

Edited September 17, 2011 by Lynxus