Storm/convection Discussion

[Thundery wintry showers]

Had to pop down to Norwich from Cleadon today to fetch my laptop- saw some impressive convection around Peterborough on the way back (5-6pm) but I think the electrification must have died out by the time it got there.

[Phil UK]

A surprising day indeed. At 3:15pm, a storm blew up out of literally nowhere over Solihull.

Thought I'd imagined thunder at first but in all I counted a separate 22 further deep rumbles, I'm guessing all but one were caused by intra-cloud lightning, the other was a visible CG. Not much in the way of rain but it came, (to use the pun) out of the blue.

Lasted around half an hour or so but still a pleasant surprise nonetheless bearing in mind there was no weather activity of the sort forecasted in my part of the world today.

Phil. (Pics just after the storm was moving on ENE).

Edited August 25, 2009 by Phil UK

[Costa Del Fal]

That first picture phil was very similar to what we had here too. Wispy looking skies. Very nice.

Had some rumbles here too.

Edited August 25, 2009 by Blizzards

[Coast]

Well, for what it's worth, here's what people are saying:

Storm Forecast

Valid: Wed 26 Aug 2009 06:00 to Thu 27 Aug 2009 06:00 UTC

Issued: Tue 25 Aug 2009 23:27

Forecaster: KOROSEC

A level 1 was issued for W Mediterranean, coastal areas of southern France and SE Spain mainly for excessive rainfalls and large hail.

SYNOPSIS

An upper trough over SW Europe slowly moves NE-wards while transforming into a weak upper level cut off low by the end of forecast period. The British Isles are affected by the remnants of extra tropical storm Bill in the morning hours as quite deep cyclone races through. Another short wave trough crosses Baltic sea during the afternoon hours. At surface, a weak front is extending from Scandinavia into central Europe and convective activity is expected along this boundary. A weak surface cyclone along the Spanish and French coast brings another day for severe weather threat.

DISCUSSION

...British Isles...

Rather deep cyclone with a cold front rapidly crosses British Isles during the morning hours. Models simulate an impressive SREH and shear values along the warm front, but there are almost no signals of instability present. If at least some CAPE becomes available and convective cells form, a tornado event cannot be completely ruled out given the very strong LL shear (10-15m/s) and SR helicity (>500m^2/s^2) in place. A few convective storms are possible more to the south along the cold front where some CAPE could release.

UKASF and TORRO - all quiet on the Western front!

Doubtful for thunderstorms, but there could be a bit of wind and precip around later!

[dogs32]

Spain is where i Would love to be at the moment..Lots of Cape predicted over the next few days...

thanks for the update Coast

[Jane Louise]

Well, for what it's worth, here's what people are saying:

, but there could be a bit of wind and precip around later!

Thanks for posting these charts up Coast. I always look forward to reading them every morning!

Edited August 26, 2009 by Ross B
No need to quote all the images again, ta.

[Shiny_Bottom_1]

Can anybody advise as to what the ppn might be like between about 5pm and 8pm around here (probably best to use Ashby de la Zouch as the closest location to where i'm going to be)?

I've got my brother in law (9 years old) here, and he wanted to go fishing later on.

Looking at the forecast, it varies. In general, it does look like it might clear by 5pm, but there are some variances in the forecast, and a chance it might still be raining (and dont really want to take him to sit in the rain).

Cheers.

Chris

[dogs32]

I know its far from home but just discovered this of a live cam in Kansas with sound of a storm in the background

http://www.tomnliz.com/Live_Little_House/

havent seen any lightning yet but heard lots of thunder and the rain is getting heavier

Edited August 26, 2009 by dogs32

[Shiny_Bottom_1]

Interestingly, i'm not sure if today is panning out as planned.

I'm quite sure most forecasts were for rain this morning and early afternoon (the heaviest of it anyway).

In fact, BBC rain graphics were showing it to be raining by 10am.

Looking at the METO radar, it looks dry, with what looks like showers (rather than persistant rain) approaching from Wales.

Unless they intensify, it could be a drier day than planned (or knowing my luck, later than planned).

Even the sunshine keeps poking its head through (winds have picked up though).

Edited August 26, 2009 by Shiny_Bottom_1

[Ross B]

Went up the Chilterns this afternoon to watch the storm gust it's way nicely from Thame over to Aylesbury.

Nice captures Daniel! I didn't realise you had captured lightning in the first one until i clicked it

[Phil UK]

Have to say that this ex hurricane 'Bill' has not quite lived up to the expectations that I've seen forecast over the past couple of days. Not much rain and not much in the way of wind either. Have seen the Sun pop out on occasions since 9:30 this morning with just fast moving clouds.

Funny how yesterday no storms were forecast for my region, showers maybe but not a full blown thunderstorm and yet on the other hand, today was supposed to be quite a wild one with gales in places. (Maybe it was exclusively meant for Cumbria and southern Scotland which seems to have bore the brunt of the rain so far).

I dunno! As my Mum says... The weather is what is is outside. But she changed her tune quick on 2nd February when 3 inches of snow greeted us.

Phil. (Need to fix my sig properly. Tried to add to it last night and it all went crazy!)

[Wilxy]

Have to say that this ex hurricane 'Bill' has not quite lived up to the expectations that I've seen forecast over the past couple of days. Not much rain and not much in the way of wind either. Have seen the Sun pop out on occasions since 9:30 this morning with just fast moving clouds.

Funny how yesterday no storms were forecast for my region, showers maybe but not a full blown thunderstorm and yet on the other hand, today was supposed to be quite a wild one with gales in places. (Maybe it was exclusively meant for Cumbria and southern Scotland which seems to have bore the brunt of the rain so far).

I dunno! As my Mum says... The weather is what is is outside. But she changed her tune quick on 2nd February when 3 inches of snow greeted us.

Phil. (Need to fix my sig properly. Tried to add to it last night and it all went crazy!)

Well the effects of ex bill have for sure been felt here with very strong winds here maybe as high gusts as 50 mph

[Harry]

Agree with most of the comments on here - today has actually been by and large another pretty decent day. Has been a fair bit of cloud around from time to time, with literally spits of rain for about 90 seconds this morning, otherwise it has been warm (at least 23C), blue skies at times too.

Not quite the wet and windy day I was expecting, even if the SE was meant to miss the worst of it regardless.

[Phil UK]

Well, I in part retract what I said in my last comment.

Thought that it was over but not quite. For the last hour and a half (ish) there has been very intense drizzle. Could even see it blowing down in sheets as you would if it was heavy powder snow. The wind did get up slightly more but I think the worst seems to have now passed.

Friday could well be interesting, Weather09. But as long as it's a dry and reasonable Bank Holiday weekend then that will do for me.

Don't forget that this will be the last Bank Holiday until Christmas. Might even snow on the next one but way too far to predict as yet. (I'm not the stick my neck out get it wrong three times in a row Met Office after all! )

Phil.

[maidstone weather]

Read this today and thought to myself, do Met Office forecasters read these forums, in particular, ones where we discuss meteorological terms? This is from Met Office's 6-15 day forecast:

"Elsewhere generally dry and warm, the best of the sunshine in the southand east, becoming very warm in the southeast. But it doesn't last,with rain and perhaps thunderstorms spreading eastwards Tuesday and Wednesday marking the start of another changeable spell of weather forthe UK"

I like when they use 'thunderstorms' in their forecasts rather than 'showers' "..which could possibly turn thundery" Hopefully this is something they continue to do.

Ties in well with the GFS run I saw this morning, +20C upper air close to the UK! No doubt some downgrades but perhaps a 'proper' plume for the start of next week?

Edited August 26, 2009 by maidstone weather

[Costa Del Fal]

Friday is still looking good. Cape is similar, TT Index excellent, LL Shear even better on recent runs, Lapse Rates are very good. So if things fall into place then its looking very good.

Current Fax Charts suggest a trough for most passing early on in the morning but then perhaps another passing through later in the afternoon which will probably utilise the best of the storm ingredients available on the day.

Lets hope things dont change too much.

[A.J]

yep, and the 3-5 day forecast from the met-office uses the words 'thunderstorms'...something for us recently storm-starved west midlanders perhaps??

[azores92]

yep, and the 3-5 day forecast from the met-office uses the words 'thunderstorms'...something for us recently storm-starved west midlanders perhaps??

does it? all i can see is scattered heavy showers

[A.J]

does it? all i can see is scattered heavy showers

That should have read '6-15 day forecast'........Yes, I know....I should've gone to specsavers!

[Phil UK]

Nice back end to ex-hurricane, Bill...

And last, but not least, Stratus Fractus with hint of Iridescence...

Phil.

Edited August 26, 2009 by Phil UK

[Costa Del Fal]

yep, and the 3-5 day forecast from the met-office uses the words 'thunderstorms'...something for us recently storm-starved west midlanders perhaps??

No youve cursed it now. Tomorrow it will go back to saying rain with a risk of it turning thundery.

[Harry]

yep, and the 3-5 day forecast from the met-office uses the words 'thunderstorms'...something for us recently storm-starved west midlanders perhaps??

I think this is probably yet to update! As per the charts late last night and early this morning, then I would very much agree with the MetO

GFS has rather typically, wiped out the threat of a plume event - certainly wiped out the chance of widespread thunderstorms, or even isolated ones which it was keen on yesterday and early this morning!

I will be interested to see if this is a GFS 'miscalculation', or if the other charts will follow GFS' suit in eradicating our plume chances!??

As for Friday, the SE is not looking less favourable at present - late thursday/early friday will give a better indication.

Edited August 26, 2009 by Harry

[Coast]

yep, and the 3-5 day forecast from the met-office uses the words 'thunderstorms'...something for us recently storm-starved west mid landers perhaps??

Well I'm not holding out for it, but Friday into Saturday has 'indications' and 'trends' :ph34r:

But hey, you know how it is...... :ph34r:

Incidentally, I found this link to some useful learning material if you're interested in CAPE and CIN (no, not sin!): www.e-education.psu.edu Vertical wind shear: www.e-education.psu.edu and elevated storms: www.e-education.psu.edu + I also discovered this stunner on the site:

Edited August 27, 2009 by Coast

[Harry]

Incidentally, I found this link to some useful learning material if you're interested in CAPE and CIN (no, not sin!): www.e-education.psu.edu Vertical wind shear: www.e-education.psu.eduand elevated storms: www.e-education.psu.edu + I also discovered this stunner on the site:

Awesome! Cheers Coast

[Coast]

Awesome! Cheers Coast

Also forgot this one on Bow Echos: www.e-education.psu.edu

There is some really interesting reading on the site and of you're bored over the BH weekend, you can pick up a lot! Main site: www.met.psu.edu