Storms and Convective discussion - 1st June 2020onwards

[ChannelThunder]

Seeing some lovely CBs to the north now. Once again stuck in the alleyway of nothingness between all the fun!

[staplehurst]

12z soundings from weather balloons launched at Nottingham and Herstmonceux highlight the subtle differences at play this afternoon between the heavy showers currently over the Chilterns / Oxfordshire vs Hampshire to Devon. I've modified both for typical surface temperatures and dewpoints present in the areas of interest, and both yield around 400-500 J/kg CAPE. However, Nottingham is much drier aloft and so this limits the depth of convection to around 18,000ft with cloud tops of -20C or so. Conversely, the profile ahead of the occlusion over central southern and SW England is moister with less mid-level inhibition, and so convection here can grow to 27,000ft or so with cloud tops potentially as low as -40C. Hence there has been sporadic lightning from the deeper convection over southern England, and so far none with the convection immediately behind the front currently over the Chilterns (started life over Beds/Herts at lunchtime).

Some modest 0-6km shear, around 25kts, over southern England too where convection is also being forced more strongly by confluence zone. Shower training/backbuilding over similar areas brings the risk of flash flooding given moist profiles and prolonged downpours.

Edited June 11, 2020 by staplehurst

[Flash bang flash bang etc]

12 minutes ago, jake44 said:

well well well looks like thunderstorm alley at the moment for the uk fingers crossed ramsgate will get some at some point

[Justin1705]

Some towering cumulus visible in south Essex however I’m sure we won’t get anything! Had my fix the other day can’t be too lucky !

[Justin1705]

Some towering cumulus visible in south Essex however I’m sure we won’t get anything! Had my fix the other day can’t be too lucky !

Edited June 11, 2020 by Justin1705

[convector]

10 minutes ago, staplehurst said:

12z soundings from weather balloons launched at Nottingham and Herstmonceux highlight the subtle differences at play this afternoon between the heavy showers currently over the Chilterns / Oxfordshire vs Hampshire to Devon. I've modified both for typical surface temperatures and dewpoints present in the areas of interest, and both yield around 400-500 J/kg CAPE. However, Nottingham is much drier aloft and so this limits the depth of convection to around 18,000ft with cloud tops of -20C or so. Conversely, the profile ahead of the occlusion over central southern and SW England is moister with less mid-level inhibition, and so convection here can grow to 27,000ft or so with cloud tops potentially as low as -40C. Hence there has been sporadic lightning from the deeper convection over southern England, and so far none with the convection immediately behind the front currently over the Chilterns (started life over Beds/Herts at lunchtime).

Some modest 0-6km shear, around 25kts, over southern England too where convection is also being forced more strongly by confluence zone. Shower training/backbuilding over similar areas brings the risk of flash flooding given moist profiles and prolonged downpours.

how did you get access to real weather balloon data? i can usually only find forecast skew-t's

[staplehurst]

1 minute ago, convector said:

how did you get access to real weather balloon data? i can usually only find forecast skew-t's

Various places, but the University of Wyoming often has data you can either download in raw format to import into software such as RAOB, or you can use the pre-made SkewTs in GIF or PDF format:

http://weather.uwyo.edu/upperair/sounding.html

[Guest]

I think underwhelming was a good description of what just passed over! 

[matt111]

That was a bit of a letdown considering how promising it looked beforehand. Sun back out now

 

[Cornishdave]

I’m a lurker here who never posts but is always watching! Cracking cell just gone past me outskirts Exeter, thunder ever couple mins. Nothing mad but great cloudscape and enough to get my thunder fix for now! Mass rainfall too! Very happy 

[Flash bang flash bang etc]

Looking straight up

 

[Zak M]

Really hope the SR and MR are correct for the early hours of Saturday.

   

[Mapantz]

Not a single rumble of thunder heard from all of that, even the rain is splitting in two before it gets here.

[Paul Sherman]

3 minutes ago, Zak M said:

Really hope the SR and MR are correct for the early hours of Saturday.

   

Good Good - Zippo over the Cone of Silence - Looks legit

[Ryukai]

3 hours ago, Mapantz said:

Temp responding nicely in the sunshine here. Most humid it has been for months!

Humidity started going silly last evening for us here, just the other side of the valley has that opaque washed-out look to the colours (due to the moisture in the air) and that's barely half a mile distant. 

[PurpleLED]

11 minutes ago, Zak M said:

Really hope the SR and MR are correct for the early hours of Saturday.

   

bout 75 miles or so south would be very nice, ah well ill see some flashes hopefully.

[Wilxy]

Torrential rain here although no thunder. 

[Ben Sainsbury]

1 minute ago, TomW said:

Torrential rain here although no thunder. 

Just waiting on that shower now to move WSW, pleaseeee!

[Guest]

Very interesting picture on Twitter of what looks a wall cloud/mesocyclone almost sat on the ground near Ringwood, Dorset I think. 

[sheikhy]

19 minutes ago, Zak M said:

Really hope the SR and MR are correct for the early hours of Saturday.

   

That will probably get downgraded too!!!either too far north or will just end up as big band of boring torrential rain!!

[Ben Sainsbury]

2 minutes ago, Alderc said:

Very interesting picture on Twitter of what looks a wall cloud/mesocyclone almost sat on the ground near Ringwood, Dorset I think. 

Link?

[Guest]

4 minutes ago, Ben Sainsbury said:

Link?

 

[matt111]

@Alderc @Ben Sainsbury Presume it's this one 

 

[Paul Sherman]

7 minutes ago, Alderc said:

 

Paul Hunter just sent me a picture as well looks Supercellular for sure from his pics

[Flash bang flash bang etc]

Showers beginning to develop just south and west of London. These moving westward and into a favourable environment. Could see something pop up here over the next 45 mins