Convective/Storm Discussion early to mid June (merged)

[chapmanslade]

22.6C here and convection kicking off to my South, although not forming huge towers yet. There is a slight cap today with a few small inversions, but I would think that temperatures will be sufficient, combined with sea breeze induced wind conversion zones for a few showers along the M4 corridor later. How developed these become is down to very small local factors.

[*Stormforce~beka*]

Right you lot whats my chance for today? And is this stupid cloud going to disappear to even give me a chance!! ... Still no storms since last August for me --- Getting close to Pauls record! We must be twinned ...

[Stuart]

just seen the bbc weather forcast they did not say anything about storms for the weekend

Edited June 9, 2007 by Stuart H

[Costa Del Fal]

Oh yeah BBC Predicts Thunderstorms/Thundery Showers for Us on Monday.

As ive Looked so far This goes for Birmingham, Worcester, Bristol, Yeovil, Taunton and Ilfracombe.

So its Just the South West Part of the UK That may see something on Monday.

Edited June 9, 2007 by Blizzards

[*Stormforce~beka*]

Right, Fine, I'll ditch it then! Long shot as always for me. See ya laters chaps x

[chapmanslade]

Temp 23.6C with a dew point of 17C now, lots of convection to the south

[Stormraider]

Some nice towers going up all over the place round here esp to the North.

[Karen Ann]

Temp 23.6C with a dew point of 17C now, lots of convection to the south

That'll be the ones I'm looking at to my N and NE then! Going up quite nicely now, been watching them periodically for the last hour.

[Lynxus]

Fair bit of convection around gloucester/cheltenham however the sky is still very misty.. Im hoping it will burn off but until this goes theres no chance of storms

[Stuart]

lots of convection here

[Joneseye]

Afternoon all!

Warm and humid here with lots of convection kicking off in the last couple of hours after the temperature reached 24.2C. The latest dew point isn't anything to write home about at only 9C mind.

[Nick F]

Sea breeze front has become evident across Sern England this afternoon, amongst the general cu bubbling up over England and Wales, this front or wind convergence line will slowly move inland towards the M4 as the sea breeze strengthens this afternoon, this convergence line will most likely be the area where TCu will build high enough for heavy showers to form.

Recent Wind chart chows convergence line over Sern counties:

1200hrs satellite shows general fields of Cu bubbling up inland, but notice distinct line of cu with clear air to South over Hants, Dorset and Somerset - this the sea breeze front:

GFS shows moderate CAPE values to tap into, quite a moist/humid boundary layer with upper cold pool over Channel aloft creating steepening lapse rates this afternoon, at 15z convergence line/SB front moves further inland:

[Supacell]

Are cloud tops likely to rise high enough for the formation of thunderstorms?

[Lynxus]

Sounds good to me.

I love it when convergence lines are directly over me 15:00

Fingers crossed

[Joneseye]

Sea breeze front has become evident across Sern England this afternoon, amongst the general cu bubbling up over England and Wales, this front or wind convergence line will slowly move inland towards the M4 as the sea breeze strengthens this afternoon, this convergence line will most likely be the area where TCu will build high enough for heavy showers to form.

Recent Wind chart chows convergence line over Sern counties:

There are already some echoes appearing in the New Forest area along the convergence zone.

[Andy Bown]

Temp 23.6C with a dew point of 17C now, lots of convection to the south

And over Salisbury Plain now, I guess as the zone Nick mentioned is edging Northwards.

Touching 25c with high humidity too.

[Nick F]

Are cloud tops likely to rise high enough for the formation of thunderstorms?

Interestingly, the Herstmonceux 00z Ascent, assuming the airmass hasn't altered much over Sern England, shows a rather moist profile upto around 600mb which would become unstable with surface heating and help of lift. There were small weak inversions at 00z, but with a convective temp of 23-24C, an adjusted skew-t (shown below) shows that the inversion/caps would be overcome and that 300-400 j/kg CAPE could be tapped into:

Could tops 300-350mb, so thunderstorms are possible IMO.

[chapmanslade]

26.0C with dew point backed off a little to 15.9C, visibility has improved to show some half decent towers, some now showing pileus cloud type layers suggesting they are starting to push through the inversion layer.

Is that rain on the radar to the North of Poole, or is it anaprop, or even high based stuff not reaching the ground ?

Edited June 9, 2007 by chapmanslade

[*Stormforce~beka*]

Temp here 25.5c - dew point at 14.6c - some hope after all then ...

[Nick F]

12z Herstmonceux sounding is out, although the ascent itself didn't suggest much instability with with the noon surface temp there - with lapse rates not quite steep enough (though no capping now), a convective temp a few degrees higher, say 23C, would yield some moderate CAPE with cloud tops reaching 300mb:

Few echoes over Dorset atm.

[Paul]

I think the Dorset echos are anaprop at the moment.

[chapmanslade]

Does it mean the cloud tops are currently where I have marked with a red line ? (pileus cloud showing)

[Lightning Hunter]

I've just come back from underneath the cells over Hants/Dorset. Very poor visibility, and very capped from viewing from the south. Underneath, light rain and drizzle, odd large raindrop, some very wet patches on A31 near Burley, but nothing of note. No structure visible due to haze underneath.

This was about 30 minutes ago.

[chapmanslade]

I've just come back from underneath the cells over Hants/Dorset. Very poor visibility, and very capped from viewing from the south. Underneath, light rain and drizzle, odd large raindrop, some very wet patches on A31 near Burley, but nothing of note. No structure visible due to haze underneath.

This was about 30 minutes ago.

Definite cap here still, but very vigorous convection below that. Temp flattening out at 26.1C with a dew point of 15.2C - awaiting the sea breeze front which normally arrives here around 16.00

[Supacell]

Definite cap here still, but very vigorous convection below that. Temp flattening out at 26.1C with a dew point of 15.2C - awaiting the sea breeze front which normally arrives here around 16.00

I'm surprised the cap hasn't been broken with temps that high. Maybe the front you mention will help force those clouds up through the cap. I'm hoping they then move northwards towards the Midlands.