Convective Storm/Discussion thread - 11/06/16 onwards

[James_southampton]

From nothing to monsoon rain and thunder in 5 mins! Literally formed overhead!

[TropicThunder]

Can hear thunder from that little cell that's popped up around Hedge End.

[William Grimsley]

Massive clap of thunder then!

[Raidan]

I am so confused i  just checked the lightning map and there is a big red blob over me and around me yet i have seen or heard nothing!

[tomp456]

19 minutes ago, East_England_Stormchaser91 said:

Well done to those in the south getting a dosage of storms  

12z has gone off on one again for storm porn!! A carbon copy of 28/06/12! I do hope the GFS is onto something here. 

So we can expect a bust then!

[James_southampton]

Unsure if they can be made out but some beefy cells visable from by view. Probably 70+ miles away 

[William Grimsley]

This cell is incredibly close to here, pouring just a few miles away whilst it's dry and sunny here!

[James_southampton]

Another cell forming overhead 

[ChezWeather]

Interesting video from yesterday, not uploaded by me

Not sure about the claims of a supercell, anyone care to comment views on this? 

[Dean E]

New cell forming all around me! Thunder heard

[William Grimsley]

Just had another torrential downpour here!

[Frosty hollows]

What a difference a day makes....my road 24h ago and tonight

[East_England_Stormchaser91]

47 minutes ago, ChezWeather said:

Interesting video from yesterday, not uploaded by me

Not sure about the claims of a supercell, anyone care to comment views on this? 

Looks good, but not quite a supercell. For a true supercell, there needs to be an adequate amount of wind shear aloft generally overlapping a very unstable environment, usually resulting in pea to golfball sized hail or in some cases, larger. Very frequent lightning activity and an associated mesocyclone where the tornado potential is at its greatest. Supercells in the northern hemisphere will also generally travel in the direction of S-N, SSW-NNE or SW-NE and take a right turn from approximately 10-30 degrees of the mean steering winds aloft (300-500 hpa). 

This however could be perceived as a supercell as the rotating winds around the centre of the low steer it anti clockwise, giving an image of rotation which can clearly be seen. 

Good video nevertheless! 

Edited June 17, 2016 by East_England_Stormchaser91

[TheToastPeople]

Cant help but notice the blue sky being replaced with low dark clouds, rain building towards the bedford/milton keynes area on the radar

[James_southampton]

http://m.dailyecho.co.uk/news/14565274.T20_match_cancelled_after_groundsmen_failed_to_cover_the_square/

 

Looks like the unexpectant rain caught the groundsman out at the rose bowl to. Its about a mile from me.

[Azazel]

2 hours ago, ChezWeather said:

Interesting video from yesterday, not uploaded by me

Not sure about the claims of a supercell, anyone care to comment views on this? 

Certainly evident rotation.

[Bolt from the Blue]

Chased a cell near Yeovil earlier, plenty of CGs. The storm died out before it reached me, here are the best screen grabs

Edited June 17, 2016 by AIRMET

[Nick F]

3 hours ago, ChezWeather said:

Interesting video from yesterday, not uploaded by me

Not sure about the claims of a supercell, anyone care to comment views on this? 

Having seen numerous supercells in the U.S.A, I can confidently sat that isn't one in the video, a supercell would have a rotating mesocyclone in the updraft area with separate rain core and evidence of striations around the perimeter of the storm. Can't see any signs of rotation in the storm, think the way the camera is angled in different positions gives the illusion of rotation.

Need strong wind shear for a supercell in this country, been little or no vertical wind shear this week, which has meant pulse type storms where downdrafts aren't separated from updrafts - which eventually suffocates the storm. We have see funnel or weak tornadoes this week, but you don't necessarily need a supercell to produce those, just surface convergence, low cloud base and weak wind aloft. Supercell would produce a stronger updraft rotation = larger hail and stronger tornadoes, given right conditions, than covergence / weak shear environment ever could.

 

Edited June 17, 2016 by Nick F

[Harry]

Strictly FI...but anyone with a weak heart should definitely not look at the GFS charts....uuummmmmmm, beeeeeeeeeerrrrrr!!!! *groooog*

 

[Buzzard]

1 hour ago, TheToastPeople said:

Cant help but notice the blue sky being replaced with low dark clouds, rain building towards the bedford/milton keynes area on the radar

Yep pretty heavy shower here in LB and perhaps the days last bit of lightning to my SW over the Chilterns. Funny as been benign all day, quite nice. 

[Harry]

4 minutes ago, Nick F said:

Having seen numerous supercells in the U.S.A, I can confidently sat that isn't one in the video, a supercell would have a rotating mesocyclone in the updraft area with separate rain core and evidence of striations around the perimeter of the storm. Can't see any signs f rotation in the storm, think the way the camera is angled in different positions give the illusion of rotation.

Need strong wind shear for a supercell in this country, been little or no vertical wind shear this week, which has meant pulse type storms where downdrafts are separated from up drafts which eventually suffocates the storm. We have see funnel or weak tornadoes this week, but you don't necessarily need a supercell to produce those, just surface convergence, low cloud base and weak wind aloft. Supercell would produce a stronger updraft rotation = larger hail and stronger tornadoes, given right conditions, than covergence / weak shear environment ever could.

 

At the risk of sounding like Gordon Brown...I agree with Nick. There is undoubtedly some broad rotation, but largely at the base, possibly the downdraughts colliding with the prevailing winds leading to some veering?? But as you look up the profile of the Cb there appears to me to be little or no change in wind direction...if you look at any of the supercell vids online, the veering winds are evident at different heights up the cloud. 

[Maxxie]

9 minutes ago, Harry said:

Strictly FI...but anyone with a weak heart should definitely not look at the GFS charts....uuummmmmmm, beeeeeeeeeerrrrrr!!!! *groooog*

 

Monday looks good

[Stormyking]

Wooo we finally got a proper storm between 5pm and 5:45pm, had bowls towards the North of the island, this cell developed which started popping out a few CGS, and then drove right under it, thunder was proper loud, and quite frequent too  Proper over the moon! 

[Nick F]

Storm clouds over north Kent near Sevenoaks looking SE from the North Downs this afternoon, not very electrically active but turned the hillier roads into rivers driving around under it.

With regards to the next storm potential, both 12z GFS and ECMWF hinting at strengthening WAA ahead of digging trough to west of Iberia and Biscay Weds/Thurs combining with a thundery low moving NE across northern France to bring a threat of convective rainfall to the SE early Thurs. ECMWF CAPE charts on wxbell show several  100 j/kg Thursday morning too. Long way off though, with the usual shift of the risk away on to the near continent possible! Here's precip from ECMWF for 06z Thursday ...

Edited June 17, 2016 by Nick F

[chapmanslade]

32 minutes ago, Harry said:

Strictly FI...but anyone with a weak heart should definitely not look at the GFS charts....uuummmmmmm, beeeeeeeeeerrrrrr!!!! *groooog*

 

CAPE isn't the be all and end all mind

 

It is only 'potential' without a trigger