Storms and Convective discussion - 20th March 2023 onwards

[Eagle Eye]

Thursday 

Convective Outlook ️

 

Heavy showers will push NE around the late morning. Behind these showers will quickly follow an unstable atmosphere allowing CAPE to rise in the SW, where an AOI was issued.

 

We did not issue a SLGHT due to the saturated profiles.

Tomorrow is looking much more interesting and I think it may be the first moderate over England of the year. Annoyingly,the timings for me are quite difficult but Sunday looks better for me anyway. We'll have to see.

Storm season has gone off to a quick stsrt despite no big setups coming up from France yet. Makes it harder for them to bust as they stop in the channel which is a huge plus for homegrown Storms.

[ChannelThunder]

This morning's weak front has left behind a legacy of AC Cas, which is always promising to see. Along with Dan's SLT down here, my interest has been piqued. A very low-end set-up though of course 

[*Stormforce~beka*]

Something going on around the channel islands? Likely to come this way?

[Jamie M]

Loving the instability in the sky 

[ChannelThunder]

Nice little storm in the channel, heading towards Worthing.

[Metwatch]

Looking pretty interesting from a brighton webcam in the last 20 minutes.

[Metwatch]

A little time lapse from here not long ago, some weak mid level instability but otherwise dry and warm. Tomorrow looking like the main course for storm lovers alike. 

[Jamie M]

Crept above 18C and look at that instability in the clouds, certainly not moaning about it

[The Tall Weatherman]

Some sferics off the south coast heading N/NW. Dan on his forecast earlier mentioned storms might get stronger over land.

[Mapantz]

Lightning detected.

[Flash bang flash bang etc]

Sun is pretty hot here in the west of Surrey

[Flash bang flash bang etc]

HOT cold HOT cold HOT cold WIND calm WIND calm HOT calm WIND cold HOT

[ChannelThunder]

52 minutes ago, Jamie M said:

Crept above 18C and look at that instability in the clouds, certainly not moaning about it

Classic thundery skies!

[The PIT]

Interesting some showers with thundery rain popped up out of nowhere here. Could be good news for places to the north west of Sheffield.

[Harry's House]

1 hour ago, The Tall Weatherman said:

Some sferics off the south coast heading N/NW. Dan on his forecast earlier mentioned storms might get stronger over land.

Did not hear thunder at my house in Pagham despite strikes well within 10km according to lightning maps.

[Rufus Butterfield]

Looks sort of thundery here with the altocumulus and showers moving in.

[Thomas Green]

A short bust of very heavy rain just came over while very muggy definitely feels stormy with some interesting cloud structures, lovely smell of Petrichor in the air

[It's a Philcast]

The build up just passed overhead with the band of showers south of Brum here in Bromsgrove...skies gone green heading out towards Redditch and lickey hills...Big one for Brum maybe? 

[Hirudine]

Just started chucking it down here, but just heavy rain- no sferics.

[matty40s]

The High Plains of Northamptonshire...

[Metwatch]

Certainly some interesting clouds about even though the heavy shower missed me. I can see some convection in the distance towards Birmingham though (first picture) and it's extremely moody to my north/east. 

 

 

Edited May 4, 2023 by Metwatch

[Eagle Eye]

Convective Outlook ️

Thu 04 2200 May - Fri 05 2300 May

A small plume of moist Theta-E air along with surface heating and the most bouyant surface-boundary layer air parcels of the year so far will provide ample 3CAPE for strong convection. Though shear is fairly unfavourable (weak), the EL is quite deep and so tall convection is still possible.

Convergence with strong PV lobes will provide that strong bouyancy and that appears to run quite deep into the atmosphere and so could counteract the amount of shear and aid storm height. With storm height, the potential for lightning tends to increase and so we have issue a low-end moderate.

Generally this favours quite a high amount of entrainment CAPE. With moderately favourable kinematics and quite high CAPE. 1000 J/KG of CAPE appears likely in areas quite wide and the strongest we've seen so far this year which is a huge favour towards why we introduced the moderate risk.

Despite the moderately saturated profiles, those shouldn't be too much of a worry for lightning potential though very organised potential is low. Some weak clusters may form given forcing but the main problem is lack of deep-layer shearing so mostly pulse thunderstorms appear to be the main mode.

Just north of London there are some very bouyant air parcels mid-aftenrnoon which would suggest very deep convection relative to the time of year is possible but highly saturated profiles have kept us from extending the moderate down towards there. Instead, in the moderate area, there is a lot less over saturation and the soundings run quite typical to a high-end setup in England. If it weren't for the weak shearing, I suspect it would be a high end moderate but the weak shear keeps organisation from happening so we are likely to keep at sparodic lightning, frequent for a time.

The max height of storms won't be realised if air parcels can't stay in the bouyant and less than over saturated areas for long enough given the weak shearing in place. However, I suspect that even if this were the case some quite strong storms may still occur in the moderate area just not as frequent lightning as was possible. There's no real way to tell at the moment.

In high end American setups, the more parallel an air parcel stays to the moist air mass, the better chance of breaking a CAP there is. There is no real CAP in place here but the air parcel movement should be fairly parallel to the mid-level flow aiding storm height plausible and the length the pulse storm can occur in. However, this is very experimental of me.

Given strong lapse-rates, surface based storms and moderate PWAT, small (<2cm) hail is quite plausible and heavy rainfall likely if hit by a storm. Along with frequent lightning for a time in the strongest areas of CAPE.

[Thunders]

Just now, Eagle Eye said:

Convective Outlook ️

Thu 04 2200 May - Fri 05 2300 May

A small plume of moist Theta-E air along with surface heating and the most bouyant surface-boundary layer air parcels of the year so far will provide ample 3CAPE for strong convection. Though shear is fairly unfavourable (weak), the EL is quite deep and so tall convection is still possible.

Convergence with strong PV lobes will provide that strong bouyancy and that appears to run quite deep into the atmosphere and so could counteract the amount of shear and aid storm height. With storm height, the potential for lightning tends to increase and so we have issue a low-end moderate.

Generally this favours quite a high amount of entrainment CAPE. With moderately favourable kinematics and quite high CAPE. 1000 J/KG of CAPE appears likely in areas quite wide and the strongest we've seen so far this year which is a huge favour towards why we introduced the moderate risk.

Despite the moderately saturated profiles, those shouldn't be too much of a worry for lightning potential though very organised potential is low. Some weak clusters may form given forcing but the main problem is lack of deep-layer shearing so mostly pulse thunderstorms appear to be the main mode.

Just north of London there are some very bouyant air parcels mid-aftenrnoon which would suggest very deep convection relative to the time of year is possible but highly saturated profiles have kept us from extending the moderate down towards there. Instead, in the moderate area, there is a lot less over saturation and the soundings run quite typical to a high-end setup in England. If it weren't for the weak shearing, I suspect it would be a high end moderate but the weak shear keeps organisation from happening so we are likely to keep at sparodic lightning, frequent for a time.

The max height of storms won't be realised if air parcels can't stay in the bouyant and less than over saturated areas for long enough given the weak shearing in place. However, I suspect that even if this were the case some quite strong storms may still occur in the moderate area just not as frequent lightning as was possible. There's no real way to tell at the moment.

In high end American setups, the more parallel an air parcel stays to the moist air mass, the better chance of breaking a CAP there is. There is no real CAP in place here but the air parcel movement should be fairly parallel to the mid-level flow aiding storm height plausible and the length the pulse storm can occur in. However, this is very experimental of me.

Given strong lapse-rates, surface based storms and moderate PWAT, small (<2cm) hail is quite plausible and heavy rainfall likely if hit by a storm. Along with frequent lightning for a time in the strongest areas of CAPE.

Ohh

 

1 minute ago, Thunders said:

Ohh

 

Not worth staying up tonight then?
 

[Eagle Eye]

3 minutes ago, Thunders said:

 

Not worth staying up tonight then?
 

Not really. Isolated showers with a few lightning strikes but not much tonight. May be a bit tomorrow morning just before or at sunrise with a renewed pulse. Might be good for pictures but you'd be very lucky to catch lightning tonight.

[Thunders]

Just now, Eagle Eye said:

Not really. Isolated showers with a few lightning strikes but not much tonight. May be a bit tomorrow morning just before or at sunrise with a renewed pulse. Might be good for pictures but you'd be very lucky to catch lightning tonight.

I’ll keep a close eye on the radar then. I’m a light sleeper anyways