Storms and Convective discussion - 25th July 2021 onwards

[alexisj9]

35 minutes ago, NUT said:

Not sure if it can be verified but read on facebook on one of the weather pages apparently there's flash flooding in the isle of wight

Just looked on radar they have heavy rain stuck over them, back building, or just staying there, while the front of it weakens while moving away east

[BrickFielder]

Not really a classic thunderstorm day. Upper level disturbance with jetstreak over running the southwest. Complicated by Eumetsat images suggesting modelling slightly off.

Favourable areas looking like Wales and Midlands late afternoon and perhaps towards London early evening. Low level wind convergence suggested with South West and South Coast areas most likely to see convergence. Instability looks tied to humidity and highest in the Bristol area.

 

 

Yes that is pretty weak instability and when you look at cloud cover coming in from Ireland even what little is suggested might not occur.

From those charts looks like heaviest convection would be in the southwest, but forecast skewTs are telling a modified story affecting depth of convection (cloud height).

Cloud height potential for the Midlands looks slightly better than for South West.

All needs to be taken with a pinch of salt especially when seeing todays satellite images but worth keeping an eye on. My take would be instability is too weak for much more than an isolated storm, but it is interesting modelling agrees on precipitation for London area mid evening (May have missed something about the upper dynamics here).

[chapmanslade]

1 hour ago, MP-R said:

Unlikely to get anything here until this sheet of mist and low cloud does one. Very cool too at 15 degrees.

And yet 30 miles away we have very string sunshine and rapidly building convection, back building cell over Trowbridge is producing very large spot totals of rain but dry 5 miles away.

[MP-R]

13 minutes ago, chapmanslade said:

And yet 30 miles away we have very string sunshine and rapidly building convection, back building cell over Trowbridge is producing very large spot totals of rain but dry 5 miles away.

Send the sun here please. Still grey and cool here.

[emmett garland]

Some catastrophic flooding there on the Isle of White 120mm at Ventnor..

[ztam]

Here on the isle Of wight. We have had awful flooding, homes and businesses flooded, roads closed and a landslide. 

Just had warnings for more rain to come. 

[alexisj9]

4 minutes ago, ztam said:

Here on the isle Of wight. We have had awful flooding, homes and businesses flooded, roads closed and a landslide. 

Just had warnings for more rain to come. 

That sounds nasty. I hope that back building line leaves you soon.

[matty40s]

West end of the Northampton cell , which is not producing any ground reaching precipitation at the moment!!

[ancientsolar]

flash flooding looks like a very real possibility today  - not much to report in SE Wales yet , ~ other than to say some quite fast developing showers just to my west, ~ very slow moving.
~ More focused on the radar between Salisbury and Westbury ~  

 

[ancientsolar]

left picture ~ Clouds to the East of blackwood, towering some what but a lot further to go  mid picture NW ~~ and final picture is SW which is looking somewhat more aggressive.
 

[matty40s]

LANDSLIDE FEARS AS FLOOD WATER RIPS APART VENTNOR CASCADES

WWW.ISLANDECHO.CO.UK

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Fears of a potential landslip in Ventnor have been sparked as floodwater from the town above has begun tearing through the Cascades this morning (Monday). Over 30mm of rain has...

 

[Jamie M]

On 02/08/2021 at 10:27, Flash bang flash bang etc said:

Excellent capture. Several potential funnels there by the looks of it

Never seen anything like it from a timelapse. Convergence lines are fascinating to be under!

[Atmogenic]

Getting pretty dark here at gordinton 

[WeatherWatchmanG]

5 minutes ago, Frosty hollows said:

If he's symptomatic he should do a PCR as it's more reliable.

Plenty of decent sunny spells in between cloudy periods. Lovely cloudscapes too!

that message was deleted because well it's wrong place for that. Looking at the weather forecasting I can't see this so called heatwave coming so we won't see any explosive plumes just more rain.

 

Convective Weather

WWW.CONVECTIVEWEATHER.CO.UK

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Forecasting thunderstorms and severe convective weather across the British Isles and Ireland for up to the next 5 days.

Quote

 

Day 1 Convective Outlook

VALID 06:00 UTC Mon 02 Aug 2021 - 05:59 UTC Tue 03 Aug 2021

ISSUED 06:24 UTC Mon 02 Aug 2021

ISSUED BY: Chris

A weak short-wave trough will dive southeastwards across Ireland and southwestern parts of Britain today and will help to generate scattered showers and perhaps a few isolated thunderstorms by the afternoon mainly across parts of SE Wales and SW England. 

 

Ahead and near the short wave, CAPE values of around 300 J/kg will develop across the slight area in combination with weak surface convergence and some orographic enhancement. Profiles are rather warm with ELTs of only around -15C and with the lack of any significant instability or shear, lightning risk will be limited. This is considered a quite low-end SLGHT risk area. 

 

Even with the lack of shear and instability, weak surface convergence and orographic lift may lead to the development of a few funnel clouds during any more significant updrafts that can develop. 

 

Like yesterday, the main hazard today will localised heavy rainfall where some places may see between 20-30mm of rain, particularly around SE Wales, Gloucestershire, Worcestershire, Warwickshire. 

 

An ISOL area has also been issued for much of Ireland, which will see more of an area of rain associated with the shortwave, however some embedded convection is possible there with a very low-end potential of a few lightning strikes. 

 

 

Edited August 2, 2021 by WeatherWatchmanG

[ancientsolar]

First Sferics near Hereford?

[dr weather]

34 minutes ago, ancientsolar said:

First Sferics near Hereford?

I took this facing North.

I think the Hereford cell is the one on the left behind the grey scud. (Hereford is about 40 miles from me as the crow flies.)

 

Edited August 2, 2021 by dr weather

[FBR]

Heard a couple of rumbles out west from here in Gloucester. Skies very dark in that direction 

[matty40s]

Several attempts at funnels from the convergence line so far.

Northampton cell to it's right end still not sparking..

Edited August 2, 2021 by matty40s

[Karl83]

The movement of the clouds has been incredible this evening. Captured this when I left work and sat in the car park. Missed some belting lightning strikes,  though.

I can see the storm just north of my house and the rain band! Must go out!

Edited August 2, 2021 by Karl83

[SilverWolf]

Just missed out in Stroud! There was a weird rotation in the cloud and a lot of wind and low, very potent looking cloud… then it rained and had a few rumbles of thunder. Looked very promising on the radar an hour before. Oh well, next time! Maybe later in the week… 

[I remember Atlantic 252]

cell developing over Stone/north Stafford, very angry skies here

[dr weather]

2 hours ago, SilverWolf said:

Just missed out in Stroud! There was a weird rotation in the cloud and a lot of wind and low, very potent looking cloud… 

Could have been this one? I took the photo between 1830-1845. The cloud is north of Bristol. (The lowered cloud is to the right, but doesn't show up very well in this picture, unfortunately - but I was keeping a close eye on it.)

 

Edited August 2, 2021 by dr weather

[Karl83]

Hi all, I took this short hyperlapse yesterday before the storm hit here. Please could someone explain the rotational looking movement? Is this the convergence of winds?

 

Edited August 3, 2021 by Karl83

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Tue 03 Aug 2021 - 05:59 UTC Wed 04 Aug 2021

ISSUED 08:08 UTC Tue 03 Aug 2021

ISSUED BY: Chris

A slack pressure pattern across the British Isles will allow for isolated to scattered showers to develop quite widely in response to daytime heating. However, lapse rates and ELTs are quite limited and with CAPE of only 200-300 J/kg lightning is considering only a low risk today, and thus only an ISOL risk has been issued. 

There is a zone around Lincolnshire, Cambridgeshire and westwards toward Birmingham and the north Midlands that seems to be the focal point for some slightly heavier showers and thus the risk in this zone is slightly elevated compared to elsewhere. 

http://convectiveweather.co.uk/forecast.php?date=2021-08-03

 

[dr weather]

35 minutes ago, Karl83 said:

Hi all, I took this short hyperlapse yesterday before the storm hit here. Please could someone explain the rotational looking movement? Is this the convergence of winds?

 

 

Great video! What speed is the timelapse at? Was this the storm that was active around 1730-1845?