Convective / Storm Discussion Thread - 27th Feb onwards

[carl1980]

19 minutes ago, carl1980 said:

Starting to rain,just heard thunder in the distance I think

Think it was a plane taking off from Liverpool 

[NO LONGER POSTING]

Picture of the front going through too good luck further north today 

[Man With Beard]

Awesome thunderstorm last night between 4 and 5am!! From a quick read in here, looks like we weren't the only ones!!

[Buckster]

whats with the heavy showers coming into the mid-south - s-east ?

thought they weren't predicted to come in land this morning? 

[Norfolk Sheep]

BBC forecast just now not really going for anything much tbh, certainly not compared to other convective forecasts. At least the H word wasn't mentioned!

[Stuart]

Storm Forecast
Valid: Sat 27 May 2017 06:00 to Sun 28 May 2017 06:00 UTC
Issued: Sat 27 May 2017 06:51
Forecaster: TASZAREK

A level 1 was issued for N Spain, N France and Benelux mainly for the large hail, severe wind gusts and excessive precipitation.

A level 1 was issued for E British Isles mainly for large hail, severe wind gusts, excessive precipitation and in lesser extent for isolated tornado event.

SYNOPSIS

Spanish plume with a steep lapse rates and rich boundary layer moisture continues to develop over W parts of Europe. A typical for this feature ridge extends from NW Africa up to N Germany. A small shortwave providing lift moves trough British Isles, N France and Benelux in the afternoon hours. Although high shear values are displaced from the best instability areas, severe thunderstorms capable of producing large hail, severe wind gusts and heavy rain are possible. A broad thunderstorm activity within the long-wave trough is also possible on the other side of the ridge over Balkan Peninsula and parts of E Europe. However, due to small wind shear and weak instability severe weather potential over this area is strongly limited. Isolated storms with a heavy precipitation potential may develop over W and CNTRL Alps, but due to strong uncertainty regarding CI, no level threat is issued for this area.

DISCUSSION

... W Europe ...

The mixture of elevated mixed layer with lapse rates exceeding 7 K/km along with low-level moisture pooling (mixing ratios ~ 12-13 g/kg) and strong diurnal heating, develops a moderate to high instability (ML CAPE ~ 1500-3000 J/kg) in the belt from N Spain up to Benelux. DLS is not very high and amounts mostly 10 m/s (apart from N edge of France where 15 m/s may be available) which limits supercell potential and overall severity of convective cells. However, thanks to high thermodynamic instability large hail locally exceeding 3-4cm cannot be ruled out. Very large hail may occur if thunderstorms will develop in the better shear environment over N edge of France. Slow motion of the cells and high PW (~ 35mm) will also favour heavy rain events and a possible local flash flooding. Local severe wind gusts due to microburst phenomena are also involved. Limitation of this forecast is associated with the uncertain magnitude of the cap which may limit CI, especially over N France. The magnitude of lift seems to be also not very high, even besides WAA.

Severe thunderstorms will be also possible in the warm sector over E British Isles. Although these stay under weaker thermodynamic instability area, trough centre is closer and thus provide better lift and overall kinematics. Thunderstorm developing in this area may be capable of clustering into multicells capable of producing severe wind gusts and heavy rain. Few large hail incidents exceeding 2-3cm also cannot be ruled out. A marginal tornado potential also exists over tritple-point in E-CNTRL British Isles where low-level shear and helicity will be enhanced.

Majority of surface-based thunderstorms capable of producing severe weather will develop in the afternoon hours over N Spain, N France and E British Isles. In the evening hours, thunderstorm should move to Benelux and become elevated. A band of storms (squall line) moving through North Sea is also possible.

... SE Europe ...

Strong diurnal heating, enhanced low-level moisture due to evapotranspiration and lack of cap will favour "internal-airmass" convection over Balkan Peninsula, E Ukraine, SW Russia and Turkey. ML CAPE is predicted to be mostly small, locally moderate (up to 1000 J/kg). Along with weak environmental wind shear severe weather potential within these storms is strongly limited. However, few local events of heavy rain and severe wind gusts cannot be ruled out, but the overall threat seems to lie below level 5% severe probability.

http://www.estofex.org/cgi-bin/polygon/showforecast.cgi?text=yes&fcstfile=2017052806_201705270651_1_stormforecast.xml

 

[Supacell]

So if I want to see anything today it looks like I will have to head north, the showery band moving towards me has fizzled out. I cannot see it turning thundery again now.

Looks like the thundery stuff last night remained way to the south and west of here.

The Estofex forecast above interests me.

[philglossop]

What a night. That was the best storm here for over 20 years just insane levels of lightning.

At least 2 houses hit in Mutley. Then second cell travelled East of me towards Ivy bridge and Dartmoor. 

One for the memories. Now just muggy and misty mind 

[Thunderstruck]

Little line of rain over Sussex and SW London sort of area that looks like it might be heading this way. Doesn't seem electrified though.

 

Spoke too soon. Sferics SW of Tunbridge Wells!

Edited May 27, 2017 by Jcweather

[Stozzy]

Im goin to York races today , any chance there could be some storms there ? Looked further north and west on BBC forcast

[Guest]

12 minutes ago, Supacell said:

So if I want to see anything today it looks like I will have to head north, the showery band moving towards me has fizzled out. I cannot see it turning thundery again now.

Looks like the thundery stuff last night remained way to the south and west of here.

The Estofex forecast above interests me.

Yep the showery band is a hindrance at the moment.  Thinking of heading NE myself, but will read around for opinions first

[Sussex Jules]

Couple of rumbles and some big fat rain drops which meant had to dash out and rescue furniture that had been left out overnight. Wasn't expcting to receive anything today hence leaving stuff out overnight. Second shower just come through a bit heavier and a flash just now.

[Storm mad]

Well I've just out of the window and there are big towers to the south and south West....look to be developing rapidly...so.maybe a chance here...meanwhile Sunday nights potential action on the bbc graphics looks like being West of here...but will take with a pinch of salt until tomorrow....best of luck to everyone..

[Thunderstruck]

Yes I've got visual of that too. Put out quite a few strikes over SE London by the looks of it

[sunnijim]

Rapid convection in SE London in the last twenty minutes.

Heavy convective rain just started and first rumble of thunder heard.

[Boro Snow]

Well looking at the forecast on here we have gone from 80% to 32% storm risk overnight and it's expected to stay dry. Surely that's not the case for my location I thought I was in a good spot 

[Storm mad]

Black to the south West so Base visible...still nothing heard but this looks like quite a mature storm...other towers going up too...

[Thunderstruck]

Very bright echoes around the Orpington area, and I do believe it's heading this way!

[Tom Jarvis]

All high bases convection in Sussex. Not surface based yet and all the lightning is in the clouds good luck to the people further north

[Buckster]

I didn't think any storms were predicted for the S-East this morning ?

when I look at the charts nothing really immediately noticeable on them for this morning ?

[THE MISSFITS]

Morning everyone! We don't post very often (I aim to change that this year) but the Hastings webcam may be about to give us a show. Nothing here in Marlow at the moment but we should have some reports tomorrow and / or Monday.

https://www.beaming.co.uk/company/hastings-pier-webcam/

[Gordon Webb]

you can trace the SE rain back NW which I think is the trough that was expected to track NE during the morning , of course I could be completely wrong

Edited May 27, 2017 by Gordon Webb
correcting spelling

[Farmer Dave]

Just heard a rumble! 

[Thunderstruck]

Nearest strike now 21.2 miles away, so slowly getting closer. Haven't seen a morning storm in a while

[East_England_Stormchaser91]

Already surpassed 21c here, and can see a very distant huge looking CB way to the South. Hoping that line going through London will ignite even more on its way N/NE.