Convective / Storm Discussion - 27th July 2013

[Captain Shortwave]

Hmm that cell over the Caen area looks to have quite a good trajectory at the moment. Looks to be tracking towards Kent and Sussex, then up the eastern half of East Anglia.

[shaky]

The 06z wrf nmm shifts things westwards slightly again!!its got some real torrential rain and storms across the east midlands from this evening until the early hours of sunday!!am gona try not to take too much note of it though cos this nmm keeps changing every run!!

[A.J]

from reading the posts in this thread this morning, any new members wouldn't have a clue what the forecast is, I mean, it's almost like chinese whisper in here....lol

 

Estofex issued warnings late last night to cover the forecasting period up to 06z tomorrow, and too much has been made (incorrectly) of the Benelux MCS. This system was never seriously progged to affect the SE, more the near continent, so the very fact that members reported audible thunder earlier this morning is a promising development.

 

The warnings issued by Estofex, Meto, and other agencies refer to a frontal wave developing currently to the SW of the UK over Western France & Biscay. The eastern flank of this Wave will destablize to encourage strong to severe thunderstorms to develop in a area of high moisture & warm air advection in conjunction with surface & mid level instability. These storms will affect the low countries and may affect parts of SE England during the forecast period.

 

The warnings also cover the risk of heavy rain & localized flooding for more central & western parts of the UK due to high PWAT (Precipitable water) values in the air mass, this saturated profile will inhibit sferic activity on the western flank of the frontal wave (and on the frontal wave) but does not preclude it

 

In my opinion, nothing has really much changed from where we were last night. The same areas that are at risk from last nights forecast and still at risk, so in closing, watch the radar, pay attention to hi-res modelling and try and avoid the temptation of getting caught up in the inevitable 'ramp/downgrade' posts!

[Adi F]

Can't believe anyone is writing anything off at this stage...gobsmacking to be honest!!

 

 

Sadly people writing it off on here is more predictable than the storms. The day has not even started yet. I was thinking I would head for Beachyhead earlier this morning but I am waiting to see now, it is shaping up nicely.  

[cheese]

Lunch time forecast really put the nail in the coffin for any widespread storms tonight just mentioning the odd flash lightning possible. Instead the focus was on heavy rain. Local forecast didn't even mention lightning at all but then did say the afternoon would be wet and then in the next breath said it would be mostly dry until evening.

All eyes on tomorrow then.

Really? I watched the BBC lunchtime weather and it didn't appear anywhere near as bad as you are making out. The local weather was pretty bad though.

[chionomaniac]

A lovely line of storms is forming from Exeter southwards to France. Worth watching these will be.

[Dean E]

Really got some development in the Bay of Biscay now, as one storm exits into Northern France, another fire's up straight away. This is looking more threatening too.

 

I think the MetO are playing it safe, like people have said, no modern model can predict where a storm or MCS will form, just a general area.

 

SM

[BA Baracus]

A quick shower in the Dewsbury area just now. Coming in from a south easterly direction. Skies temporarily very dark.

[Dean E]

Sadly people writing it off on here is more predictable than the storms. The day has not even started yet. I was thinking I would head for Beachyhead earlier this morning but I am waiting to see now, it is shaping up nicely.  

 You might not need to move Adi... famous last words? 

 

SM

[PolarWarsaw]

I'm not sure why everyone is screaming downgrade? As far as I'm concerned anywhere away from SE/East Anglia were never in line for storms, it was just about a very heavy band of rain moving north with convective elements and the odd rumble of thunder. That's what looks like happening? As far as I'm concerned the 'Thunderstorm' threat is far wide and greater tommorrow and Monday.

[Evening thunder]

Just had a brief very heavy shower, more went west of here but it had some very big thundery drops in.

 

Interesting line of heavy showers south of here with sefrics in too now! didn't really expect this.

[Harry]

On the road :-) 3G sim working a treat (no I'm not driving lol!)

[Roger J Smith]

I don't see any downgrade in the setup at all, the fact that the leading wave missed to the east is beside the point as the event was always expected to be the developing wave over France. With temps in central France above 30 C and signs of subsidence aloft over south central England (7-10 C dp) the future evolution is fairly obvious, wave will rapidly destabilize after crossing Channel and the climatology of these types of events is usually an overnight rainfall max just to the west and north of the developing low, which suggests heaviest rain for the east Midlands. A secondary region of moderate rain will be found west of the main band through inland Wales, Severn valley extending into Lancs.

 

My prediction for 24h amounts (mostly 6h as it works out) would be

 

50-100 mm east Midlands, Yorkshire with slight risk of 125-150 mm localized amounts

25-50 mm east Anglia, Kent, greater London

20-35 mm east Wales, Severn valley, Lancs, also later into northeast England, southeast Scotland

15-30 mm Thames valley inland south central

 

Also expect this to become very intense for lightning by the overnight hours. This event will release the considerable charge built up over 3-4 weeks of dry weather in many locations.

 

Research shows a strong energy peak at 03-04h overnight so would speculate the most intense thunderstorms will be in a zone from western Kent east London northwest through Cambs into Notts, Lincs and southeast Yorkshire.

 

The very least I would expect is about half this intensity which would still be a significant storm event for many. Map shows the expected pattern, should verify at multiples of 15 mm so about 75 mm for the red zone, 60 mm for the purple, etc.

 

 

 

[Adi F]

 You might not need to move Adi... famous last words? 

 

SM

Famous last words indeed. I moved from Warwickshire on Monday evening and missed everything that happened over night. Although I did have a problem with my camera hence leaving so not too upset The problem has been rectified now though so bring it on.

[Harry]

Estofex upgraded....levels 2 and 3 remain in place!!! New Level 3 for C/S France.....wow!!!!!

[LJS22]

http://www.livestream.com/rcdawlish

 

Raining heavily in Dawlish too

[Adi F]

On the road :-) 3G sim working a treat (no I'm not driving lol!)

 

Where you heading Harry... Oh ark at you, being driven whilst storm chasing. How decedent.

[Harry]

I don't see any downgrade in the setup at all, the fact that the leading wave missed to the east is beside the point as the event was always expected to be the developing wave over France. With temps in central France above 30 C and signs of subsidence aloft over south central England (7-10 C dp) the future evolution is fairly obvious, wave will rapidly destabilize after crossing Channel and the climatology of these types of events is usually an overnight rainfall max just to the west and north of the developing low, which suggests heaviest rain for the east Midlands. A secondary region of moderate rain will be found west of the main band through inland Wales, Severn valley extending into Lancs.

 

My prediction for 24h amounts (mostly 6h as it works out) would be

 

50-100 mm east Midlands, Yorkshire with slight risk of 125-150 mm localized amounts

25-50 mm east Anglia, Kent, greater London

20-35 mm east Wales, Severn valley, Lancs, also later into northeast England, southeast Scotland

15-30 mm Thames valley inland south central

 

Also expect this to become very intense for lightning by the overnight hours. This event will release the considerable charge built up over 3-4 weeks of dry weather in many locations.

 

Research shows a strong energy peak at 03-04h overnight so would speculate the most intense thunderstorms will be in a zone from western Kent east London northwest through Cambs into Notts, Lincs and southeast Yorkshire.

 

The very least I would expect is about half this intensity which would still be a significant storm event for many. Map shows the expected pattern, should verify at multiples of 15 mm so about 75 mm for the red zone, 60 mm for the purple, etc.

Noooooooo!!!!!!!!! I'm heading SE!!!!!!

[Buckster]

I'm more optimistic about our chances in Essex/Kent/London area now than I was last night

 

I think we'll certainly get something exciting later

[The PIT]

Really? I watched the BBC lunchtime weather and it didn't appear anywhere near as bad as you are making out. The local weather was pretty bad though.

Guess you didn't listen properly.   It did mention Thundery showers over Scotland and southern England. The ones of southern England merging into a larger area of heavy rain. However the emphasis was on the heavy rain with the odd flash of lightning possible tonight. No mention of widespread thunderstorms at all. I'm happy they're down playing it the more they jump around on TV the less likely anything is to happen. Now since they mention possible two inches of rain tonight I better hold fire on starting my monthly report about being a very dry month. 

Edited July 27, 2013 by The PIT

[Harry]

Where you heading Harry... Oh ark at you, being driven whilst storm chasing. How decedent.

Dymchurch (where else lol)...though judging by Roger Smith I might be making an error.....who knows lol!! We had spectacular lightning Monday night and we were on the edge of proceedings....still might get good lightning from the continent later if all does stay off shore.What is also promising is that estofex have elected not to alter the zones highlighted this morning!!! Edited July 27, 2013 by Harry

[cheese]

A shower has appeared on the radar near here, and I can see a shower passing to my west. Well, at least something has appeared..

[Adi F]

 You might not need to move Adi... famous last words? 

 

SM

 Check your messages SM

[dave48]

Heavy Echos across the channel now showing sferic returns.

[Adi F]

Dymchurch (where else lol)...though judging by Roger Smith I might be making an error.....who knows lol!! We had spectacular lightning Monday night and we were on the edge of proceedings....still might get good lightning from the continent later if all does stay off shore.What is also promising is that estofex have elected not to alter the zones highlighted this morning!!!

I might see you over there mate. Where do you park?