Storm & Convective Discussion - 20th August 2015 onwards

[<<Ryan>>]

Just heard a lovely deep rolling peel from the channel - though haven't seen a flash yet! Odd

I'm down hastingS and seeing flashes and bolts of lightning every minute or two, so unsure why you can't? The odd deep rumble also

[Harry]

I'm down hastingS and seeing flashes and bolts of lightning every minute or two, so unsure why you can't? The odd deep rumble also

I have now, a few really impressive flashes

This lot definitely sliding past - might get luckier later if more storms fire further west

Edited August 29, 2015 by Harry

[Hirudine]

Ahahhahahahaha check the beast out in the Atlantic lmfao..

Not sure I've ever seen something like that before..

Cool

 

That is quite bizarre looking, like someone plonked a big ole storm infront of an industrial strength fan!

[matt_in_dudley]

Typical, was in Hastings this morning! Back home in Dudley now! 

[Team Jo]

Well this is odd- I'm sure I can hear rumbling here, but blitzortung and the nw detector are telling me otherwise, we don't usually get anything from the channel storms this far north,

[Speedway Slider]

What is the situation weatherwise for Monday evening.......? Looking at met office forecasting, it looks like rain from Sunday evening constant through to early hours of Tuesday! With temps more associated with March/early April...

Is this gonna change much do you think? Surely we need more warmth to initiate any thundery stuff....?

[<<Ryan>>]

Im really sorry that you have to look at such a bad picture - but it's the best i could get with my cheap smartphone. If you look close enough you may just see the 'lightning'  Missed some monster cg's out to sea though! Can see the flashes of lightning across in France, pretty constant stuff over there..

[Nick F]

As the storms rumble through the Channel and across the far north of France tonight before clearing NE along the coast of the Low Countries, tomorrow looks to see a repeat performance later in the day according to GFS, though UKMO/BBC forecasts backed up by UKMO meso indicate that brighter or sunny conditions developing across the far SE may trigger isolated hvy showers or thunderstorms afternoon/early evening - more particularly Kent and Sussex, also risk of storms coming up from the Channel late evening/ Sunday night.

 

Have issued a storm forecast for Sunday: http://www.netweather.tv/index.cgi?action=convective;sess=

Edited August 29, 2015 by Nick F

[<<Ryan>>]

That new clump of storms just exploded into life - was at 98 strikes a minute just now! I can dream..

half an hour later - still going strong at 100+ strikes a minute just now. Shame i'm not down Hastings anymore..

Edited August 29, 2015 by <<Ryan>>

[TropicThunder]

Just been up to the roof terrace and can see the odd very distant flash. Mostly to the SE but a few directly to the East as well so they must be quite close to the mainland.

[Flash bang flash bang etc]

Must be a supercell - checkout the Pourville webcam from France - an absolute beast!

Probably the most prolific storm of the summer - blitzortung can't keep up!

[Flash bang flash bang etc]

http://www.viewsurf.com/univers/surf/vue/12264-france-haute-normandie-pourville-live

The link to Pourville live cam if anyone is interested in watching the southern side of the storm. Not the greatest quality but would love to be there now watching it pass by...

[Condor Vitesse]

any cams in the Dover area..

[Flash bang flash bang etc]

Hastings pier cam could be a good one - except for all the street lamps :-(

Some bright echoes coming from a rain storm developing and moving into Southampton area. Maybe this could produce a few sparks as it passes over London later?

Edited August 30, 2015 by Flash bang flash bang etc

[Condor Vitesse]

Just found a Folkestone one. Hopefully will get interesting soon 

[TropicThunder]

Hastings pier cam could be a good one - except for all the street lamps :-(

Some bright echoes coming from a rain storm developing and moving into Southampton area. Maybe this could produce a few sparks as it passes over London later?

Yes I've had my eye on that too, unfortunately it's not been kicking out any sferics though, but might see a bit of heavy rain for a while.

Edited August 30, 2015 by TropicThunder

[Condor Vitesse]

Lightning now showing on  Hastings pier webcam 

[Updraft]

lots of lightning over the channel here in Dover but it looks like the whole lot is missing us and it heading into northern France/Belgium!

[Convective]

That storm near Calais really is quite impressive. I've never seen a strike rate like that before!

[Nick F]

Some strong wind damage reports from West Flanders in Belgium following a severe storm that tracked through there last night, either straightline or possible tornado, no reports/survey or eyewitness accounts to suggest either way yet. Photos here: https://www.facebook.com/NoodweerBenelux

 

Large hail (3cm) reports near Eindhoven, The Netherlends too.

 

Back here, chance of some thundestorms brewing over N France crossing the Channel and glancing SE England overnight, maybe some isolated heavy showers developing before then in any warm sunny spells later across the far SE - where temps could reach 25C if the sun comes out.

 

Gatwick TAF suggest risk of thunder between 6pm tonight and 9am tomorrow:

 

EGKK 300506Z 3006/3112 04006KT 9999 SCT030 TEMPO 3006/3018 BKN014 PROB30 TEMPO 3006/3010 BKN008 BECMG 3018/3021 8000 BKN010 TEMPO 3018/3112 SHRA PROB30 TEMPO 3018/3109 +TSRA BECMG 3021/3024 2000 BR BKN003 PROB30 3100/3108 0300 FG BKN001 BECMG 3109/3112 30010KT 8000 NSW SCT006 BKN010

 

Netweather storm forecast for today issued last night:

 

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

Edited August 30, 2015 by Nick F

[Harry]

The Beeb precip model shows good chance for thunderstorms across the far SE tonight (conveniently I'm staying Dymchurch) although I'm well aware of how unpredictable it is and historically how unreliable the model the Beeb relies upon can be.

Pleasantly warm here with a notable breeze. Fingers crossed some of what I saw last night visits properly

[NO LONGER POSTING]

The further north that front goes the better, cloud breaks here now and sun trying so hard,

Beeb I don't think have a scooby, yes some models show ppn across the south, some show it merely getting Kent.

I think all summer with all the setups we have had,this has to be the most will it won't we yet.

Loads of potential, I think some people will some flashes tonight, where we'll best chances the further south East you are thats for sure

[Tamara]

Essentially the massive August B/H front stretching SW-NE from the Azores all the way to NE Europe and Russia that divides the line between the hot humid air over the continent, and the cooler maritime air to the north west (as directed by the omnipresent 2015 summer season troughing to the NW and N of Scotland) is a very symbolic close to the  summer in terms of a general synoptic pattern that has mostly dominated since the second half of June.

 

Its symbolic too, that it finally gets pushed away through tomorrow and the first part of next week, right on the cue of official start of autumn, as high pressure replaces the dominant LP trough to the NW - ending the two month sequence of heat pulses and plumes which have regularly advected north eastwards across the nearby continent, and fringed at times with southern and more especially southern eastern parts of our country

 

The stuck overall larger scale synoptic pattern with the UK being boundary line between heat and cool Atlantic air, has very much determined the knife edge nature of plume type convective events this summer, this side of the channel. Distribution of classic plume mid level heat storms as expected has been dictated by this wandering boundary - its very northern most extent generally the south eastern quadrant of the UK before briefly wandering back towards central Europe... and then returning again

 

 Other than the start of July, plume type storm potential has mainly been reserved for the SE quadrant of the country however. There has actually been relatively little Polar maritime/rPm convection this summer - although the NW of the UK has seen some this weekend f.e close to the main upper Atlantic trough.. Although perceived as an underwhelming season generally, I think this is a distinction that separates 2015 from a truly poor summer like 2012 when atlantic pulse storm convection was much more dominant then plumes. Save for the spectacular late June event - where strong destabilisation occurred over many northern and western parts and ironically convection was capped and nothing happened in the SE where the highest temperatures occued

 

The boundary distribution of elevated storms was classically illustrated last night. There are actually basically two 'sub boundaries' this weekend. First, a warm front which constitutes the northward extent of the warmer boundary, and sub 8 to 10C 850hPa uppers in the cooler maritime air north of the midlands). There is also a second boundary, which last night sat straddling the eastern channel and is now to our east over Germany indicated as a convective trough feature as indicated by todays dawn fax.

 

https://max.nwstatic.co.uk/fax/20150830.0725.PPVA89.png

 

 

This linear trough feature and associated line of thunderstorms tracking eastwards along it is an indicator of where the main theta plume lies to the south of it.

 

A sub division of warmth exists with 10 to 15C 850hPa uppers sitting over south east England (south of the main warm front,) from a main circa 18 to 21C 850 hPa heat plume over Europe. It is this, that is, and will continue to determine the thundery threat for SE parts through the rest of today and into tomorrow

 

http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2015/08/30/basis00/ukuk/t850/15083000_3000.gif.

 

The 15C 850 line curves out of Northern France in an arc, and scribes a line right through the eastern mid channel and back into the continent. Interesting that the storms last night followed almost exactly the steering winds along this second boundary (the aforementioned upper trough) with the destabilisation occurring right where the strongest theta values start being found and following the trajectory of the strong upper jet stream.

 

The slightest fraction of veer of those winds coming out from Cherbourg just enough to take the storms towards Calais rather than landfall on the far SE coast.

 

This was the split difference of outcome that determined the advisory of warnings out for possible storms across Kent in the METO forecasts yesterday. The very good post from Harry yesterday well explained the scenario and the 50/50 nature of it. Models wavered over a 30/40 mile radius of where the destabilisation would occur and the consequent path that initiated storms would take.

 

That sort of distance is a lot in the Eastern channel that separates two countries!

 

http://expert-images.weatheronline.co.uk/daten/proficharts/en/2015/08/30/basis00/ukuk/uv85/15083000_3000.gif

 

Like others in the far SE corner have posted, the regular lightning and occasional distant tremors of thunder last night, illustrate just how close and yet so far are once again the UK has been to being the 'other side' of the real heat boundary, although some of that warmth is brushing the coast here - and in truth the summer here in the far SE, closest to the main continent under the dominating synoptics this summer, does not reflect the underwhelming picture given by the overall nationwide CET figures as a whole for the season

 

There are very slack surface conditions this weekend  - almost flat calm yesterday evening (and a slight easterly breeze this morning) but as dictated by the upper steering jet, the mid level AsCas which formed in conjunction with the destabilisation boundary (which was merely some 20 miles further south in the channel) was moving at quite a pace late yesterday evening from the SW and was well lit by the moon

 

The knife edge theme fully illustrated here, and the difference between a warm dry and humid night with distant T&L and what might have been some quite severe weather as illustrated by Nick F with the damage reports of the line of storms as they headed east across Belgium, The Netherlands and lately this morning Northern Germany - along the strong jet stream that separates the main thermal boundary

 

The longevity and training nature of the storms between yesterday evening and this morning illustrating fully how a strong jet can organise storms and make them stronger

 

The METO typically might come into some criticism for nothing materialising as often happens in these circumstances, but were well justified and quite right to place an advisory with severe weather brushing so close by. This is where the risk/effect matrix plays its part.

 

An advisory is just that - it is not intended as a definitive prediction to take literally, but to illustrate the potential and possibilities that exist, especially when weighed up against the possible severity of effects

 

They are also well justified in tonights advisory warnings - more so with an overall higher risk this side of the channel likely today.

 

This morning shows quite a wide variation of temperatures across a small area of the SE. Already heading into the low 20's here with hazy sunshine and feeling humid. Whilst closer to the main straggling (epic long!) warm front which has been stuck in a zone from CS/SW England and through the more northern home counties is seeing greyer damper conditions and temperatures supressed

 

Tonight shows a similar type of sequence to last night, but with a main low pressure circulation gathering and heading NNE and the steering winds over Northern France becoming more NNE'erly, then there looks to maybe a higher risk of elevated showers and storms making landfall and perhaps greater inroads inland.

 

ECM 0z deterministic model shows quite strong initiation of storms across Northern France by late afternoon and early evening

 

http://en.vedur.is/photos/atlant_evr_urkomuspa/150830_0000_21.png

 

http://en.vedur.is/photos/atlant_evr_urkomuspa/150830_0000_24.png

 

These steered more NNE over the channel through the evening across the SE as the main low circulation tracks up from France, and then through tomorrow gradually out into the North Sea, edging the warm air and humidity away slowly eastwards.

 

This looks to take much of the day in the far east and south east. Maybe a lot of "weather" to get through before the bank holiday is finished for these parts?

Edited August 30, 2015 by Tamara

[VillagePlank]

My take for the SE tonight and overnight https://forum.netweather.tv/topic/83478-southeast-england-east-anglia-weather-chatjuly-1st-2015/?p=3253382

[Dean E]

Will be interesting to see what happens to these storms that have been rumbling since this morning. They are moving at a fair old pace.

 

 

Later this afternoon, as destabilising occurs, it will be interesting to see where it happens. Its been a sunny/hazy morning here, with temperatures briefly hitting 23c. Now down to 22c and cloudy. Very humid feeling.