Storm & Convective Discussion - 7th August Onwards

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Tue 02 Apr 2019 - 05:59 UTC Wed 03 Apr 2019

ISSUED 20:25 UTC Mon 01 Apr 2019

ISSUED BY: Dan

Elevated showers may be ongoing across coastal parts of East Anglia and Kent at the beginning of this forecast period, posing a low risk of lighting. These will soon clear, and thereafter the attention turns to the post-frontal environment already over Ireland and western Scotland, and extending across the remainder of the British Isles through Tuesday.

A potent upper trough will extend southwards across the British Isles, with notably cold mid/upper levels creating very steep lapse rates and a few hundred J/kg CAPE. Numerous wintry showers will develop, both in response to relatively warm SSTs and diurnal heating inland. The strongest cells may produce a few lightning strikes and some small hail.

Beneath the trough axis, shear will tend to be weak due to both similar speed and direction with height. However, around the periphery stronger shear will be present, particularly across southern and western Ireland and also E/SE England. Tricky attempting to be more specific to areas with a greater lightning potential given the extensive nature of somewhat marginal instability, but perhaps the best overlap of favourable conditions will exist in S + E Ireland and across the Celtic Sea towards SW England - these areas may require an upgrade to a low-end SLGT if confidence improves.

Showers inland will tend to become more isolated overnight as nocturnal cooling of the boundary layer commences, but some will likely persist aided by both upper forcing and relatively warm seas around western coasts.

http://www.convectiveweather.co.uk/forecast.php?date=2019-04-02

[Ben Sainsbury]

Might be a decent day according to ESTOFEX:

.... UK and Ireland ....

Under the core of the cold trough (even -38oC at 500 hPa), Ireland and the UK will be under the influence of strong N-NW flow. Strong surface fluxes are expected over the ocean, providing moisture to the lowest levels which can feed the instability over land, where diabatic heating of the land will provide lift to unstable air masses. Locally large amounts of small hail/graupel (even if storm cells will be moving fast) are expected, but also strong to severe wind gusts can verify, especially in Ireland in the afternoon, where there is a mid-level jet streak. 

[Azazel]

Rashes of convective showers breaking out today. My eyes are drawn to the following areas - anything in the orange zone with the potential to be a little stronger/more organised - yellow box for general squally showers.

 

 

[Azazel]

Sferic South East Wales between Newport & Gloucester.

[Mapantz]

7 minutes ago, Azazel said:

Sferic South East Wales between Newport & Gloucester.

Definitely warranted a level 2 by Estofex. 

[Azazel]

9 minutes ago, Mapantz said:

Definitely warranted a level 2 by Estofex. 

I'm so storm-starved that the 3-4 sferics being picked up around the country are making me moist.

The "mini plume" from last night has sparked into life over the continent - hope that's not the story of our summer.

 

edit: sporadic sferics appearing now - one just north of Newbury?

Edited April 2, 2019 by Azazel

[Chris.R]

I’m interested in a feature coming down early hours of tomorrow morning which seems to have a modest amount of CAPE associated with it.  Will be the best chance for my area to see some lightning and maybe back edge snow given the slack surface flow at that time. 

[Kirkcaldy Weather]

just had a hail shower here  showers in the distance earlier  

[MP-R]

Decent hail shower passing over Bristol now. Very dark.

Edited April 2, 2019 by MP-R
Photo

[Mapantz]

As reported in the Southwest regional thread.. I've just been caught out in a hail shower, the largest i've seen for a while. Only lasted a minute or so, but they were 20 pence piece sized. Amazing fallstreak as it heads Southeast.

[matt111]

Just had a decent hail shower here. 

[Frosty hollows]

32 minutes ago, Mapantz said:

As reported in the Southwest regional thread.. I've just been caught out in a hail shower, the largest i've seen for a while. Only lasted a minute or so, but they were 20 pence piece sized. Amazing fallstreak as it heads Southeast.

Have amazing fallstreak from a shower passing to my north.  Being elevated has it's advantages!

[East_England_Stormchaser91]

Nice to say I’m finally coming out of hibernation from a very unimpressive winter! 

Lets hope the convective side of things is more impressive. April off to not a bad start so far! 

[toggerob]

Showers moving through the south of Manchester currently and although not looking too great on Radar there's some quite heavy hail-cores within them.

[Weather-history]

 

[Arnie Pie]

7 hours ago, Chris.R said:

I’m interested in a feature coming down early hours of tomorrow morning which seems to have a modest amount of CAPE associated with it.  Will be the best chance for my area to see some lightning and maybe back edge snow given the slack surface flow at that time. 

An interesting line of weather just forming in the irish sea......I hope your right Chris

[Chris.R]

Expanding on my post from earlier. The WRF 12Z continues to show a signal for a trough feature associated with the coldest 500 MB temps  running SSE in the early hours. For 3 am at my location it shows a spike of CAPE to  >400 j/kg. It is also marked by a slight veering of surface win from NNW to N.   

I will report here if anything happens. 

Edited April 2, 2019 by Chris.R

[Windblade]

Lovely towers and cb's forming in towerhamlets this morning.

[MP-R]

Looks more like a front than showers to the west today.

[Windblade]

Convergence zone over london right now. Been watching the radar for the past hour. Lots of cells popping up all over. 

[steve86]

[steve86]

7 minutes ago, steve86 said:

Biggest hail I've seen here in Fareham.

[matt111]

A light hail shower here, looks like snow when watching it fall. 

[Windblade]

Just heard a loud rumble from this lot to my west, right over towerhamlets.

[Harry]

Hi all

Happy new year and storm season to you all.

Just had my first thunder of 2019, immense blue flash followed by gorgeous peel of thunder in C London - been soft hail/snowing on and off for the past hour, now absolutely chucking it down with the white stuff. Still only the solitary flash/bang though thus far! 

Fingers crossed for an active storm season this year.

Update: Been torrential snow/hail in the past 15 mins so much so it’s settling

Further update: Had a further flash and bang just now - the bang was almost instantaneous so would love to know where it hit! 

Edited April 3, 2019 by Harry