Convective/Storm Discussion Thread - 1st August onwards

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Sat 31 Mar 2018 - 05:59 UTC Sun 01 Apr 2018

ISSUED 18:57 UTC Fri 30 Mar 2018

ISSUED BY: Dan

Vertically-stacked low over eastern England will gradually drift southeastwards to BeNeLux by Saturday night. The exact location of the surface low will prove crucial to any deep convection potential - provided it is sufficiently to the west, this may allow some insolation to occur across eastern England, perhaps enough to generate 100-200 J/kg CAPE.

Low-level convergence near the surface low centre may allow a few heavy showers to develop, perhaps capable of producing some isolated lightning - though the risk is considered quite low as this depends on surface temperatures reaching 9-10C which seems unlikely should cloud cover persist. The risk is greatest over East Anglia, but confidence on lightning potential is not high enough for now to issue a SLGT.

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-03-31

[Windblade]

Wanted to say thanks to everyone who responded to my last post about the aftereffects of the ssw and what it means for storm season. I always presumed the warmer the better with storms so it's good to gain more knowledge and a better understanding of conditions that can trigger my favourite weather. 

 

Looking forward to (hopefully) some good storms this year.

[Another Kent clipper]

Day 1 Convective Outlook

VALID 06:00 UTC Mon 02 Apr 2018 - 05:59 UTC Tue 03 Apr 2018

ISSUED 21:20 UTC Sun 01 Apr 2018

ISSUED BY: Dan

On the forward side of the upper trough to the west of Ireland, strong warm advection will result in a frontal system pushing north across the British Isles, bringing rain and hill snow. Main interest will be in the post-frontal environment, as several shortwaves migrate northeastwards. 

 

The exact forecast evolution is not particularly clear-cut, with models handling the location of various features a little differently - in either case, instability is somewhat marginal until Tuesday morning when the main cold pool arrives, so despite the potential for some showers or showery bursts of rain, lightning will likely be quite sparse during this forecast period.

 

Edited April 2, 2018 by Another Kent clipper

[Chris.R]

From an imby point of view the SSW should hopefully continue to result in an increased frequency of off-shore winds here which should mean I get in with the April shower risk. Usually April showers do not exist here. 

[Windblade]

7 hours ago, Chris.R said:

From an imby point of view the SSW should hopefully continue to result in an increased frequency of off-shore winds here which should mean I get in with the April shower risk. Usually April showers do not exist here. 

Well Chris, it's been quite unsettled recently with the odd rumble and flash thrown in so the signs are looking more positive for our usual April weather. Wishing you a stormy spring. 

Edited April 2, 2018 by Windblade

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Tue 03 Apr 2018 - 05:59 UTC Wed 04 Apr 2018

ISSUED 21:16 UTC Mon 02 Apr 2018

ISSUED BY: Dan

Broad upper trough will gradually approach the British Isles from the southwest, with an upper low/shortwave tracking northeastwards during Tuesday afternoon. Lapse rates will steepen in associated with this increasingly cold air aloft, especially combined with diurnal heating inland. At the surface, a rather diffuse cold front/occlusion will push northwards and eastwards across England, Wales and the Republic of Ireland.

... ENGLAND / WALES ...

Surface dewpoints of 10C are expected across central and eastern England during the morning, but this will eventually be eroded from the west through the day as drier air advects eastwards with the passage of the cold front. Main upper forcing (and hence steeper lapse rates) will tend to arrive later, arriving over Wales around 11-12z for example, and then migrating NE-wards through the afternoon - hence there is somewhat of a lag between favourable surface conditions not overlapping more favourable mid/upper level conditions. This creates some uncertainty as to whether much deep convection can develop given increasingly dry forecast profiles and somewhat of a warm nose at 700mb.

 

Some convection-allowing models simulate several showers during the afternoon, from S + E Wales through the Midlands to Yorkshire / Lincolnshire. Given 400-600 J/kg CAPE and 30-50kts DLS, it is certainly possible some lightning activity could occur should any deep convection develop, including hail up to 1.5cm in diameter - however, confidence is not particularly high on whether many showers/storms will actually form. Given lowering dewpoints, any clouds that do form will likely be fairly high-based too. An upgrade to SLGT is possible for some of these regions if confidence improves.

 

Some showers/thunderstorms may get close to Kent/Sussex from northern France late afternoon into the evening hours, though most activity will likely stay over the nearby Continent. The approach of an upper (and surface) low from the southwest may also increase deep convection potential during the early hours of Wednesday over southern counties of England.

 

... REPUBLIC OF IRELAND / NORTHERN IRELAND ...

Behind the northward-advancing occlusion, a few heavy showers may develop during the afternoon/early evening over The Midlands northeastwards into SE Northern Ireland. Instability and shear overall are a little weaker here, and cloud cover may be somewhat of an issue, but some lightning is also possible with any stronger cells - and an upgrade to SLGT may also be considered if confidence increases.

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-04-03

[Another Kent clipper]

Well, the drizzle has gone and the sun is (kinda) shining. Presumably the trough has passed.  At this point, are things looking confident in a few hours time for some action in the British isles?

[BlueHedgehog074]

Been a few heavy showers so far in Solihull and Birmingham. Very wet around the City Centre. 

[Arnie Pie]

Theres been some potent little cells popping up over Lincoln in a rising temperature.....15 c atm

Some chance I would imaging

On rainbow watch ......but a good temp and a few cells coming up from the South which will be worth keeping an eye on

 

[MP-R]

Four rumbles of thunder here in Yatton, North Somerset.

[Chris K]

Few strikes to my southwest skirting up the Severn Estuary. I have been looking forward to the start of the 'convective season' again. 

[LightningLover]

looking on radar towards France, are french imports possible? (there are a few showers pushing into the channel currently)

[Arnie Pie]

No hogging Chris.....send em up

Totally agree its a great feeling to get my....... `excitable little kids head `  as my wife says

May the gods be with us all this season

[Summer Sun]

6 hours ago, Summer Sun said:

Day 1 Convective Outlook

VALID 06:00 UTC Tue 03 Apr 2018 - 05:59 UTC Wed 04 Apr 2018

ISSUED 21:16 UTC Mon 02 Apr 2018

ISSUED BY: Dan

Broad upper trough will gradually approach the British Isles from the southwest, with an upper low/shortwave tracking northeastwards during Tuesday afternoon. Lapse rates will steepen in associated with this increasingly cold air aloft, especially combined with diurnal heating inland. At the surface, a rather diffuse cold front/occlusion will push northwards and eastwards across England, Wales and the Republic of Ireland.

... ENGLAND / WALES ...

Surface dewpoints of 10C are expected across central and eastern England during the morning, but this will eventually be eroded from the west through the day as drier air advects eastwards with the passage of the cold front. Main upper forcing (and hence steeper lapse rates) will tend to arrive later, arriving over Wales around 11-12z for example, and then migrating NE-wards through the afternoon - hence there is somewhat of a lag between favourable surface conditions not overlapping more favourable mid/upper level conditions. This creates some uncertainty as to whether much deep convection can develop given increasingly dry forecast profiles and somewhat of a warm nose at 700mb.

 

Some convection-allowing models simulate several showers during the afternoon, from S + E Wales through the Midlands to Yorkshire / Lincolnshire. Given 400-600 J/kg CAPE and 30-50kts DLS, it is certainly possible some lightning activity could occur should any deep convection develop, including hail up to 1.5cm in diameter - however, confidence is not particularly high on whether many showers/storms will actually form. Given lowering dewpoints, any clouds that do form will likely be fairly high-based too. An upgrade to SLGT is possible for some of these regions if confidence improves.

 

Some showers/thunderstorms may get close to Kent/Sussex from northern France late afternoon into the evening hours, though most activity will likely stay over the nearby Continent. The approach of an upper (and surface) low from the southwest may also increase deep convection potential during the early hours of Wednesday over southern counties of England.

 

... REPUBLIC OF IRELAND / NORTHERN IRELAND ...

Behind the northward-advancing occlusion, a few heavy showers may develop during the afternoon/early evening over The Midlands northeastwards into SE Northern Ireland. Instability and shear overall are a little weaker here, and cloud cover may be somewhat of an issue, but some lightning is also possible with any stronger cells - and an upgrade to SLGT may also be considered if confidence increases.

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-04-03

 

UPDATE 14:01 UTC SLGTs added in light of recent radar and surface observations - still some uncertainty over true convective depth given quite dry air aloft, and reducing dewpoints during the remainder of today

 

http://www.convectiveweather.co.uk/forecast.php?date=2018-04-03

[Supacell]

Now should I be getting excited about sferics being detected around NW Birmingham/Wolverhampton? I am directly upwind but it is a distance for them to travel to get here.

[Mr_ Nexus]

Underneath those sferics and very excited here , Heavy rain and hail .

Nice way to kick off the storm season  

 

[simon1]

Thunder and lightning here for the last 20 minutes or so with some hail.

[Arnie Pie]

1 minute ago, Mr_ Nexus said:

Underneath those sferics and very excited here , Heavy rain and hail .

Nice way to kick off the storm season  

 

Yes heard in Brum from this cell over you Nexus

[Mr_ Nexus]

Lighting to the east of me now over West Bromwich , loud thunder but no rain here and the sun is out !

 

[Sparkiee storm]

Wow what a way to start the storm, quite a bit of lightning seen a CG bolt, deep and sometimes booming thunder, heavy rain and pea sized hail

Wasn't expecting that.

What a year already, snowstorms, blizzards, and now thunderstorms 

[Had Worse]

https://www.derby.gov.uk/environment-and-planning/conservation/peregrines/peregrine-camera-1/

 

A cell is about to unleash its fury. Hopefully with thunder too.

[Had Worse]

And there I was watching this https://www.derby.gov.uk/environment-and-planning/conservation/peregrines/peregrine-camera-1/

Then I hear a rumble of thunder outside my house. A quick check and there was a strike between Ashton and Mossley

[Supacell]

A storm just clipped me here in Belper. A few flashes and bangs but most went to my east. Still a nice opening to the 2018 season and more possibilities tomorrow.

[The PIT]

Sheffield Shield activating this lunch time after letting a short sharp shower through. Hence it was  a case of looking at distant dark clouds which looked thundery and the odd light rain shower here. Hopefully better tomorrow but annoying the old shield is alive and well.

[Polar Maritime]

Just heard thunder in the distance.