Storms and Convective discussion - 20th March 2023 onwards

[LetItSnow!]

My first thunderstorm of the year! Angel, Islington missed out on the severest part of it given there were some purple colours on the radar, but a short but very sharp storm with torrential rain and thunder and loud booming thunder just moved through. Nothing to shake the table in a historical sense but of interest. That helped to make March 2023 even more of an exceptionally wet month!

[BB1979]

10 minutes ago, LetItSnow! said:

My first thunderstorm of the year! Angel, Islington missed out on the severest part of it given there were some purple colours on the radar, but a short but very sharp storm with torrential rain and thunder and loud booming thunder just moved through. Nothing to shake the table in a historical sense but of interest. That helped to make March 2023 even more of an exceptionally wet month!

Yes we heard at least two of those here in the City of London. Nice to kick 2023 off especially when I wasnt expecting anything here

[minus10]

Well look at that line of showers extending all the way from Truro to London ..

Pretty wet if you are under that...

[Arnie Pie]

A shot of the cell responsible for the strike just to the West of Stafford

 

[chapmanslade]

21 minutes ago, minus10 said:

Well look at that line of showers extending all the way from Truro to London ..

Pretty wet if you are under that...

Absolutely is. Just driven under that lot which is nicely lined up with the A303 and the flooding is severe in places

[Windblade]

Can't believe this convection line stretching all the way from Dorset to Essex. Incredible.

Edit - Beaten to it by Minus10! 

 

Also looks like North London had a massive storm not long ago. Could see the Cb's from here (Welling)...

 

 

Edited March 24, 2023 by Windblade

[MP-R]

42 minutes ago, minus10 said:

Well look at that line of showers extending all the way from Truro to London ..

Pretty wet if you are under that...

That would be the Day Riviera service…

[WeatherWatchmanG]

I have some data and photos in those Tweets this happened 90 minutes ago and the hail isn't all melted.

[Windblade]

Well, one things for sure...after an absolutely pitiful winter without a drop of rain for over TWO MONTHS  my fears of this being a crappy year for storms may be premature. It's certainly been quite a stormy week so far with all parts getting in on the act at some point and not just the usual suspects (Ireland, Scotland, Wales). Hopefully this'll turn out to be a terrific year for storms. Last year was the best I can ever remember having had 17 storm or thunder days in my area. I hope this year follows suit. 

Edited March 24, 2023 by Windblade

[TwisterGirl81]

1 hour ago, minus10 said:

Well look at that line of showers extending all the way from Truro to London ..

Pretty wet if you are under that...

We've been under that line of showers most of the day in Exeter, it's just cleared us, some very heavy windy showers on and off, no thunder of lightening though....Seems to be gaining energy further east

Edited March 24, 2023 by TwisterGirl81

[minus10]

27 minutes ago, Windblade said:

Can't believe this convection line stretching all the way from Dorset to Essex. Incredible.

Edit - Beaten to it by Minus10! 

 

Also looks like North London had a massive storm not long ago. Could see the Cb's from here (Welling)...

 

 

You can just see i think the convergence zone of winds from the sw to London responsible for the convection...

..just a subtle difference in direction..

[Robbie Garrett]

Just crossing Westminster Bridge

[minus10]

Just now, Robbie Garrett said:

Just crossing Westminster Bridge

Good view from the wheel ...

[alexisj9]

40 minutes ago, Windblade said:

Can't believe this convection line stretching all the way from Dorset to Essex. Incredible.

Edit - Beaten to it by Minus10! 

 

Also looks like North London had a massive storm not long ago. Could see the Cb's from here (Welling)...

 

 

It's a convergence zone.

[Windblade]

22 minutes ago, alexisj9 said:

It's a convergence zone.

Yes I know, but I've never seen one that long and narrow before! 

[Metwatch]

Some more convection goodness this afternoon. April showers but in March! 

[Metwatch]

Sunshine illuminating the rain few minutes ago. 

[Rufus Butterfield]

Decent afternoon convection, with some mammatus.

[ChannelThunder]

2 hours ago, Windblade said:

Well, one things for sure...after an absolutely pitiful winter without a drop of rain for over TWO MONTHS  my fears of this being a crappy year for storms may be premature. It's certainly been quite a stormy week so far with all parts getting in on the act at some point and not just the usual suspects (Ireland, Scotland, Wales). Hopefully this'll turn out to be a terrific year for storms. Last year was the best I can ever remember having had 17 storm or thunder days in my area. I hope this year follows suit. 

Definitely premature. Touker doesn't get out of bed for 1% (Dragons' Den reference), and I don't get out of bed for storms before April 

[Zak M]

It's a story of rainbows and mammatus...

                     

[Metwatch]

To finish off today, a gorgeous double rainbow with decaying showers and nice sunset colours. 

Will definitely remember this day as one of the best for convective cloudscapes in March.

Edited March 24, 2023 by Metwatch

[Eagle Eye]

A case of what could have been but wasn't here.

 

 

 

 

[WeatherWatchmanG]

Did anyone else have the most vivid rainbow they've seen in a long time today? I didn't have any cameras handy but it was very bright.

[alexisj9]

1 minute ago, WeatherWatchmanG said:

Did anyone else have the most vivid rainbow they've seen in a long time today? I didn't have any cameras handy but it was very bright.

Nope, just had a nice sunny but windy day with fair weather cloud here.

[Eagle Eye]

Convective Outlook ️

 

Fri 24th 21:30 - Sat 25th 20:00

 

Another messy setup with 3 diffuse occluded fronts over England with a SEwards ejecting low will allow for some showers along the warmest (relative to the cold air around it) sector with a lick of a moderately strong Theta-E lobe advecting from the south with another low out NW acting as a 'pump' for the moisture. Though it's likely to weaken as it pushes NE there may still be a lick of up to about 400 J/KG of SBCAPE given surface heating with increasing buoyancy given the temperature difference with surface heating compared to the local environment.

 

Convergence given the PV lobe sliding across the AOI may increase the chance of lightning given stronger and taller storms but the struggke is that clustering into more of a mess is possible given saturation. Still, lightning is more favourable in this environment given the vorticity and buoyancy characteristics favour taller storms but it's not expected to be strong enough for a slight risk unless the low can slide down colder air parcels and slightly drier in the mid Troposphere especially but that's looking unlikely for now.

 

Shear is advection parallel between the occlusions in central and southern England with 200 J/KG of MUCAPE perhaps allowing for a couple showers to form capable of a lightning strike ahead of the main frontal rain which is unlikely to have much in the way of lightning.

 

Main area is definitely the North of England on the southern side of the parallel sliding of shear just above the occlusion and the greatest mix of which along with the PV and CAPE characteristics is where the AOI is placed based off current modelling.

 

The UKV shows probably the best wind convergence overall and partially as a result has some of the strongest storms in a train like line sliding across the envelope (I don't know why it's called that either) of best convection, shearing and PV around the Dumfries to Hartlepool area though the AROME also shows another one further south stretching from Londonderry to Norwich so that may also be an area to best watch out for.

 

Another help for ascent and updraft formation may be the lapse-rates given the cold upper air and -8°C 0-0.6 mile lapse-rates hail up to a few CM's big with the strongest Storms are possible.

 

So heavy rain, flooding and sporadic lightning are all possible under diurnal heating conditions though lightning is hard to gauge.