Convective / Storm Discussion Thread - 27th Feb onwards

[TJS1998Tom]

Looks like here in the North we'll miss out, maybe next time though

[Gordon Webb]

2 minutes ago, Summer Sun said:

15:45 update

Day 1 Convective Outlook

VALID 06:00 UTC Sun 28 May 2017 - 05:59 UTC Mon 29 May 2017

ISSUED 14:45 UTC Sun 28 May 2017

ISSUED BY: Chris/Dan

*Update at 1430z on Sunday to shift the main empahsis a little further west due to model trends* 

Upper trough approaching Iberia will advect a plume of high ThetaW air northwards across southern Britain through the course of Sunday evening and overnight into Monday. Destabilisation of this plume is expected, with upper forcing combining with isentropic upglide to allow areas of elevated thunderstorms to develop and expand in coverage - at least for a time - before general weakening/reducing trend is anticipated later in the night. 

Current thinking is activity will develop around the 19-22z timeframe over the English Channel / Channel Islands / SW England, growing upscale as the whole area of potential shifts NE-wards through the night. Steep mid-level lapse rates and reasonable CAPE suggests lightning will be notably frequent with any thunderstorms, especially farther east where such parameters will be more favourable.

As is often the case in such situations, there is some uncertainty as to the exact forecast evolution and position of areas most likely to experience thunderstorms - as such, the exact position of the SLGT/MDT is subject to some alterations. Some hail and strong gusts of wind will be possible with some of this convective activity.

http://www.convectiveweather.co.uk/forecast.php?date=2017-05-28

 

you can tell the uncertainty with the area been moved slight West then this in the message

especially farther east where such parameters will be more favourable.

I would take all this with a pich of salt

even many places within the moderate zone may escape

[Windblade]

1 hour ago, Harry said:

Indeed, Dymchurch!! 

Good luck to you too matey - as I said earlier I think I'm not in the best position if models are to be believed, but fingers crossed!

Hope you get better soon!

Thanks man. It's a large vitamin D deficiency and possibly other factors (they're still doing tests) which makes me feel like I'm running on empty most of the time. Surviving on chocolate, cakes, crisps and sugary drinks at the mo which give me a small burst for about an hour every so often.

As you're in Dymchurch I recommend visiting the funfair while you wait and picking up some candy floss (they used to have a wicked arcade there in the 80's but sadly now it's just fruit machine crap). I can also recommend the chippy at the other end where the road forks opposite the car park (the one literally on the corner opposite the arcade). Gotta get some seaside chips while you're there waiting for the storms, plus the sea is right behind it so theres a stellar view and plenty of space on the new sea wall to set up camera equipment.

Good luck my friend.

 

Edited May 28, 2017 by Windblade

[Frosty hollows]

1 minute ago, Gordon Webb said:

 

you can tell the uncertainty with the area been moved slight West then this in the message

especially farther east where such parameters will be more favourable.

I would take all this with a pich of salt

even many places within the moderate zone may escape

That's the nature of thunderstorms unless we get a massive mcs! We had a storm here last summer that caused flash flooding here and our local Waitrose got a direct hit, but ten miles ago they just got a thundery shower. Making a good storm is like making a magic potion. You can chuck ingredients in, but only the right combination will do the trick.Despite the drizzle temps are on the rise here, so some energy is around, but whether everything comes together at he right time is anyone's (educated) guess. It's why we love storm chasing!

[Gordon Webb]

9 minutes ago, Jcweather said:

Hmmm. Westward shift in the MDT there. Still in the slight though, and I do feel like we'll see something tonight...

difference in slight and moderate is only 15% more chance to see lightning within 25 miles of your locale , you could do that and still miss any storm directly

edit - let me know if I seem to be cluttering up thread with repeated information

Edited May 28, 2017 by Gordon Webb

[Supacell]

As has been stated previously, storms tonight are not rooted to the boundary layer but rather an elevated plume and so any cloud, rain or cold sea temperatures are going to have no effect on them. It also won't feel that humid until after the intial mess has moved through as this is the warm front on the northern edge of the humid plume. Having said that it does feel humid here with dewpoints of 13c. The question is where any storms are likely to be and just how widespread.

This afternoon the estofex forecast read like this:

"Thunderstorms weaken offshore over the English Channel with cooler LL air while crossing a sharp E-W aligned CAPE gradient. CI will be more isolated in nature, although upscale growing convection can't be ruled out with one or two clusters affecting the English Channel until sunset."

This is what we are seeing, with a weakening of thunderstorm activity as planned.

For tonight Estofex has:

"Confidence in more widespread CI increases during the night with the development of a diffuse/weak LL vortex over the W-English Channel in response to the approaching upper trough. This vortex pushes a wavy front east and a cluster of organized thunderstorms is forecast to evolve over NW-France and/or SW-UK. Forecast soundings reveal more elevated convection with MUCAPE of 1 kJ/kg and 20 m/s DLS. Also, 0-3 km shear increases to 15-20 m/s over far S-UK. Expect thunderstorms to grow upscale into a cluster of storms while crossing S-UK from WSW to ENE. Large hail will be the main risk. However, given amount of 0-3 km shear and persistent influx of moist/warm air from the S, a severe wind gust theat with a rapidly eastbound moving bowing line is possible. Weak mid-level height falls and the quasi-stationary nature of the evolving LL vortex over the W-English Channel lower the chance for a forced line of convection but indicate more of an internally organized (cold pool driven) event. Hence, the final outcome of that event depends on mesoscale impacts and nowcasting of the front's placement during the night and remains somewhat uncertain right now."

In other words the confidence grows that there will be elevated thunderstorms overnight over the Channel and push ENE and they will likely form into an MCS. The uncertainty is where they will form and this means it is not certain yet who will get them. Where they do occur it looks interesting

[Sparkiee storm]

Certainly staying up late tonight , the sky looks similar to 3rd/4th July 2015 around here, giving me hope, as we all know what happened that night. Humidity has also noticeably increased through the day.

[lassie23]

It's dark and raining but it looks like the thunder has been sucked out of these showers, pardon the technical term

[tomdewey]

I like thunder storm in 2015 over in Warminster I think it was that year and it had of lighting coming of it and I went on for ages 

[Chris K]

Met office warnings have updated and has expanded the risk zone to cover more areas further west & north than previously.

http://www.metoffice.gov.uk/public/weather/warnings

[Snoopie42]

Latest Arpege shows that the main event will not initiate until later this evening and into Monday morning sfter the really juicy airmass is insitu......certainly feels like the humidity is on the rise! Godd luck everybody and enjoy!

Edited May 28, 2017 by Snoopie42

[Gordon Webb]

32 minutes ago, Sparkiee storm said:

Certainly staying up late tonight , the sky looks similar to 3rd/4th July 2015 around here, giving me hope, as we all know what happened that night. Humidity has also noticeably increased through the day.

think that was the year bournemouth got absoulutely battered I believe , remember that night took an age to arrive then got a move on and were gone within the hour

 

Edited May 28, 2017 by Gordon Webb
more spelling mistakes

[philglossop]

Well at boyfriend's in Torpoint SE Cornwall and we abandoned BBQ due to sports of rain.

 

But it's colder here and lower humidity. Can't see a round 2 here now. Too cloudy and almost a westerly feeling tbh. 

[viking_smb]

bet you enjoyed the lightshow yesterday morning mate, we had it bad here in Cardiff as well.

[The PIT]

Quite a change in the forecast from lunchtime where it now says the first band fizzling out where before it was supposed to be expanding. The second pulse is still on the cards at the moment. We should have a good idea later on this evening.

[Windblade]

Directly underneath this cell now and we have moderate rain but not as heavy as radar imagary would suggest, although the darker core hasn't passed over just yet. It's actually pretty light under this thing, lots of light coming through which is surprising as it looked really dark when it was on the horizon coming towards us.

Edited May 28, 2017 by Windblade

[Southern Storm]

13 minutes ago, Gordon Webb said:

think that was the year bournemouth got absoulutely battered I believe , remember that night took an age to arrive then got a move on and were gone withing the hour

 

Best UK storm I have ever had the pleasure to experience, I was sat waiting in my favourite viewing spot, in and almost empty car park, let's just say that there is a lot of closet storm enthusiasts out there!

Within 5 minutes, the whole place was rammed with people trying to get pictures with their smartphones.

If we get anything close to that tonight I'll be more than happy.

This is my contribution from that night, a bit shaky but still gives a good idea to how amazing that storm was.

 

Edited May 28, 2017 by Christchurch storm nut

[Sparkiee storm]

8 minutes ago, Gordon Webb said:

think that was the year bournemouth got absoulutely battered I believe , remember that night took an age to arrive then got a move on and were gone within the hour

 

Yeah Bournemouth lit up like a christmas tree, incredible lightning rate with that storm, as it moved north it lost some of its immensity but still a good storm as the skirted us here in the West Midlands 

[Windblade]

I've been inside all day but it feels less humid to me and fresher than it has for days. I don't have measuring equipment to back this up but I'm definitely feeling cooler/more comfortable today which is nice as I can't stand being hot. The cell overhead is easing off and starting to pass northeast but no flashes or rumbles so combined with the fresher feel we may not have the right indegrients here just yet. However I think tonight may well be different as the forecast is for elevated mcs I believe.

Gonna pop off and watch the grand prix on catchup. Good luck for tonight everyone.

Edited May 28, 2017 by Windblade

[Karl83]

Cameras all charged up and ready for action! Just need to find a decent spot to set up and then hope for the best.

 

Any decent view points around the M4 corridor area that anyone can recommend? 

[matt111]

 Not that it makes much difference to tonight but the temperatures risen very quickly here in the last hour or so and it's starting to feel more humid. 

Edited May 28, 2017 by matt111

[East_England_Stormchaser91]

Popping off over Essex already! 

[Storm mad]

Massive crack of thunder...didn't expect that...made me jump

[Wet'n'Dry]

Wow!!!! Basildon just lit up, I've not heard thunder this loud in years!! CG's all over and very heavy vertical rain 

[MrNooo]

4 minutes ago, Karl83 said:

Cameras all charged up and ready for action! Just need to find a decent spot to set up and then hope for the best.

 

Any decent view points around the M4 corridor area that anyone can recommend? 

Marlborough Downs or on the Cotswold edge got to be in with a shout looking at the latest updated predictions.