Storms And Convective Discussion

[Harry]

I should've added to my post "Not that I pay any attention to the BBC forecast, as they're a complete waste of time!" :lol:

Well - certainly at storm-casting anyway!! Some many times this year, they have forecast them and nothing, or other times when to any 'lay-member' on here, there was a mod-high risk, when to them, one hour before the event the first mention of thunder is put out....

I expect a similar case tomorrow - morning will be heavier showers, lunchtime maybe a risk of thunder, while summing up in the evening "some areas saw some potent storms today"...

MetO are now going to for 'heavier showers' for especially Kent, London, Sussex and Surrey (KESUREX, YAY!!!!!), along with a decent chance for Essex and Suffolk too!!

[maidstone weather]

Harry, I can tell you now exactly when it will storm in Kent. Anytime after 8am on Sunday morning, since that is when I will be on my way to Norwich to start my 3-year course at UEA! Based on my past experience (i.e. when I went to Cumbria) I would say the chance of a storm in Kent on Sunday whilst I am away is quite high :lol:

Edited September 18, 2009 by maidstone weather

[BrickFielder]

Slight risk of storms todays for south coast, south east and east anglia although the best parameters don't overlap that well. Mid level lapse rates are fairly poor and moisture from the continent tends to be over egged at times.

There is a marked low level wind convergence zone but it does not overlap too well with surface based instability.It does give rise to a slight risk of convergence zone tornadoes, but I am not convinced convective activity will be strong enough at this point.

Looking at forecast skewT's suggest things will be rather marginal and the weak lapse rates are likely to limit cloud top heights. Some divergence of upper level winds might help, but probably not enough.

Over all I would suggest a very slight risk of storm development with storms unlikely to be severe, hence no detailed convective forecast discussion today.

[Tom Montalbano]

Thanks for that BF, as you state nothing too strong likely on the storm front. Convergence zone projected further NW now, with greater instability more likely in the extreme south and east. Although I do have a headache this morning. Ouch that hurt!

Like you Harry, noticed the Alt Cas on my journey home from Croydon to Lee last night.

We'll soon know our fate!

Regards,

Tom.

[Harry]

Thanks for that BF, as you state nothing too strong likely on the storm front. Convergence zone projected further NW now, with greater instability more likely in the extreme south and east. Although I do have a headache this morning. Ouch that hurt!

Like you Harry, noticed the Alt Cas on my journey home from Croydon to Lee last night.

We'll soon know our fate!

Regards,

Tom.

Cheers BF as ever! Not precisely the news I was hoping for, but thanks all the same.

TomSE20, it does feel like there is potential. Although it is very cloudy at the moment, it does seem like breaking up. There is certainly the feel of more moisture in the air too (perhaps that is why there is grey sky)..

As ever, a case of radar watching and chart watching through the day, and all will be revealed later.

EDIT - Cloud starting to break here :lol:

Edited September 19, 2009 by Harry

[NorthNorfolkWeather]

Harry, I can tell you now exactly when it will storm in Kent. Anytime after 8am on Sunday morning, since that is when I will be on my way to Norwich to start my 3-year course at UEA! Based on my past experience (i.e. when I went to Cumbria) I would say the chance of a storm in Kent on Sunday whilst I am away is quite high

Never fear MW, I normally work away from home and the storms that happen in Norfolk usually happen when I'm away, so unless your storm shield and mine combine to destroy all storms in South East England and East Anglia (wouldn't that make us popular here), you should have something at least.

O/T what are you studying at UEA?

[Coast]

I've been out of the loop this week and haven't had time to go through all the usual charts etc. Bricks analysis above looks good for me and the dew point is already 14.5 DgC in Eastbourne with buckets of sunshine heading for the early 20's (DgC) today.

ESTOFEX's TStorm watch area is just skimming the beach at Eastbourne, UKASF have a bigger area and more inland:

Storm Forecast Issued: 2009-09-18 22:53:00

Valid: 2009-09-19 00:00:00 - 2009-09-19 23:59:00

Regions Affected

East Anglia, Home Counties SE & CS England ( The Midlands and parts of SW England are included in the WATCH )

Synopsis

A complex setup is forecast over the United Kingdom for Saturday - a cold front moves from west to east across central and western parts of the UK during the forecast period, with an extension of the Azores High building behind it. Ahead of the cold front, a warm and slightly unstable airmass is advected northwards from France into southern and eastern England during the day. Surface LOW's are expected to develop over northern France.

As a result, during the afternoon hours, scattered heavy showers and thunderstorms, albeit quite isolated, are expected to develop across some parts of southern, eastern and southeastern England. These showers are expected to persist well into the evening, with further showers likely to develop overnight as a result of additional forcing from the approaching weak cold front.

Due to the slow-moving nature of these showers, some places may receive large rainfall amounts due to prolonged torrential downpours, which may cause flash flooding in places either as a result from either recent downpours earlier in the week or due to the dry soils as a result of the lack of recent rain.

The showers/storms are expected to be non-severe in nature. Cloud height appears to be a limiting factor, which may limit how many showers become electrified.

For 'complex' I read unlikely down here, I think anything coming this way will be out to sea or lurking over France as we have seen so many times this year.

[Nick F]

00z Trappes (Paris) ascent earlier this morning showed fairly unstable mid-levels, with warm moist advection aloft becoming increasingly unstable today in vicinity of trough over France drifting north - shown by the darker area on WV imagery:

- 00z Trappes (Paris) ascent

- 0600 WV imagery

With any cloud breaks over Nern France temps of 27-28C expected - which would make the airmass even more unstable with scattered heavy showers and t-storms breaking out during the afternoon - perhaps drifting across the SE.

If cloud breaks across London and the home Counties - could see the odd isolated heavy shower or storm develop too, as temps heat up towards the mid-20s destabilising the increasingly humid airmass drifting N.

GFS shows pool of potential instability drifting across the SE this evening/tonight, forced ascent of the warm moist air drifting north aided by the trough over France extending north across the SE this evening - so any storms may continue overnight ahead of the approaching cold front.

[magicpatch]

I'm out this afternoon, should I be prepared for a storm? The sun is breaking the cloud up around here now, the BBC said if the sun breaks you could well get a heavy downpour. Although the sun is breaking the clouds the temps aren't rising too dramatically yet, its currently 17.3c which is up 0.6c or so from an hour ago.

[Harry]

Cheers Coast/Nick F!

The glorious golden globe is well and truly breaking through here. My Dad rang a short while ago and said the weather in Dymchurch (Kent coast) is absolutely beautiful. The bit that made my ears prick up was "hazy skies"

I think tonight could be fun - even if any thunderstorms don't make it overhead, there could well be some pretty cushty light shows to my S and SE! Always happy with a good light show

[maidstone weather]

Never fear MW, I normally work away from home and the storms that happen in Norfolk usually happen when I'm away, so unless your storm shield and mine combine to destroy all storms in South East England and East Anglia (wouldn't that make us popular here), you should have something at least.

O/T what are you studying at UEA?

Meteorology and Oceanography

[Paul Sherman]

Agree with Nick the Soundings from over the Lake are very good and show a mass of Instability, this does indeed clip the South East which makes me more confident as we are not solely relying on Solar Input with this Set-Up and something could fire later this evening when the sun is long gone due to warm air advection out of NE France.

Places that look likely to get a Thunderstorm include Suffolk, Essex, Kent and Sussex but something could makes its way further West than these areas, Radar watching for once this evening, It has been a long time coming!!

Paul S

[Nick F]

Have decided to issue a convective forecast:

http://www.netweather.tv/index.cgi?action=convective;sess=83b042793c902e3ff8b5e6445ca74535

Cloud breaking nicely here ...

[Neilsouth]

Feeling good for a storm here , feels humid... hazy.. and a small breeze!. Some altocumulus this morning and last night

[dogs32]

Pure blue sky here for a few hrs...

Just hope the prediction's are wrong and we here in the South Midland's end up with a Storm..

As Jane is getting very impatient now

[Harry]

Pure blue sky here for a few hrs...

Just hope the prediction's are wrong and we here in the South Midland's end up with a Storm..

As Jane is getting very impatient now

BF was suggesting the possibility of a CZ a bit further N and W of London - so some parts of the Midlands MAY be in with a shout.

Saw the BBC forecast earlier, the most suggested was 'sharp showers' and that was exclusively for the SE...though as I have said previously, their forecasting of anything storm related is left to be desired. They were suggested the showers to last right through the night, which is something I suppose...just no confidence/inclination to suggest thunder yet.

[dogs32]

yes Harry I never give up hope...

A few times thing's have happened when we didnt expect it...

Not got my hopes up but I have a open mind as always

[Jane Louise]

Oh cool Lol...Just a slight chance of a storm will make my day

As dogs mentioned,it's a beautiful hazy clear bluesky, sunny warm day here.

Good luck Harry and co and please if you get anything down your way,please send it up my way.Im begging now,actually begging Lol

[chapmanslade]

Trough destabilising over N France now with CB reported at LeHavre. I think the cold front is moving in too fast for us here in the West Country.

[Jane Louise]

looking at the hazy sky with my sunglasses on I can see at least one cloud building high. One can hope I suppose Lol

[maidstone weather]

mist and low cloud this morning lifted to give a very warm and sticky morning with hazy sunshine. Can now see some reasonable sized puffy Cumulus clouds building above the haze layer, and if anything the sun is less bright.

[Harry]

mist and low cloud this morning lifted to give a very warm and sticky morning with hazy sunshine. Can now see some reasonable sized puffy Cumulus clouds building above the haze layer, and if anything the sun is less bright.

It is a very muggy and increasingly warm day...things slowly falling into place?

[OldGreggsTundraBoy]

I'd be surprised if there was thunderstorm this late in the year, even thought temperature and humidity are at their highest today, there not extremely high, could be wrong but uno it's not exactly 30C with steam rising from the earth peeeps! [maybe a bit in my garden because of all the watering- it's been so dry]

Good luck1!!

[Neilsouth]

I'd be surprised if there was thunderstorm this late in the year, even thought temperature and humidity are at their highest today, there not extremely high, could be wrong but uno it's not exactly 30C with steam rising from the earth peeeps! [maybe a bit in my garden because of all the watering- it's been so dry]

Good luck1!! :lol:

What? , you get thunderstorms in winter when it's snowing outside so you are abit off....

[Harry]

I'd be surprised if there was thunderstorm this late in the year, even thought temperature and humidity are at their highest today, there not extremely high, could be wrong but uno it's not exactly 30C with steam rising from the earth peeeps! [maybe a bit in my garden because of all the watering- it's been so dry]

Good luck1!! :lol:

Meaning? You get thunderstorms with air temps of 0C...?? lol. One of the best thunderstorms in recent years was mid September - if you read back through this thread, you will see some of the comments regarding said storm...it was a meany!! Besides, IF we are going to receive imports, the temps across the Channel are approaching 30C

Made an observation just now -

Humidity up + enchanced smells from the fields = ONIONS!! The air REEKS with onions, lol

We need a nice downpour/storm now just to clear to smell, lol