Storms and Convective discussion - 28th July 2019 onwards

[Hodgheg]

Im surprised this hasnt been mentioned yet.

Good to see the met sharing a grab from the Doppler

We had a nice display of mammatus from the same storm this morning. 

Edited December 21, 2019 by John90
lInk not working

[jamesbhx]

Taken from @convectivewx and https://twitter.com/danholley_ twitter accounts.

Edited December 21, 2019 by jamesbhx

[Superstormuk]

Regarding the tornado in Chertsey, I live in Virginia Water (about 4 miles away) and I happened to be getting the train at the time it touched down. I could see lots of rotation, and the whole event looked more like a summer storm rather than one this time of year. 

It's been a crazy day of weather down here. 

Edited December 21, 2019 by Superstormuk

[Robbie Garrett]

4 hours ago, Superstormuk said:

Regarding the tornado in Chertsey, I live in Virginia Water (about 4 miles away) and I happened to be getting the train at the time it touched down. I could see lots of rotation, and the whole event looked more like a summer storm rather than one this time of year. 

It's been a crazy day of weather down here. 

Rather odd how you can get a Supercell in the winter and not much in the Summer. 

[Hodgheg]

51 minutes ago, Robbie Garrett said:

Rather odd how you can get a Supercell in the winter and not much in the Summer. 

There's some interesting articles and videos about supercells associated with "cold core" lows in the USA. I wonder if this is something similar. Tornado's often occur in the UK during autumn/winter but usually associated with squalls. This event seems weird as it was quite an isolated "storm" I put storm in quotations because their didn't appear to be any lightning. 

[Robbie Garrett]

15 minutes ago, John90 said:

There's some interesting articles and videos about supercells associated with "cold core" lows in the USA. I wonder if this is something similar. Tornado's often occur in the UK during autumn/winter but usually associated with squalls. This event seems weird as it was quite an isolated "storm" I put storm in quotations because their didn't appear to be any lightning. 

I am very intrigued as there's a lot of energy involved here.  Last Saturday was biblical rainfall, same on Sunday then this cell. 

[snowrye]

Possibly a land spout

[Severe Blizzard]

There were heavy showers with lightning and thunder to the west of Guildford, moving N.E. to the north of the town on Thursday 19th. Lightning to west at 1721 and north at 1800. No thunder was heard but the storm was reported to be over Alton, Fleet and Bracknell.

Single clap of thunder heard on Saturday 21st at 0951 as large Cb moved to the N.W. of Guildford. Surface winds were S.E. but cloud movement, even at lower altitudes (1000 m) was from the S.W. Good wind shear which assisted the formation of the tornado at Chertsey. Lightning discharge was not seen on lightning detector app.

The thundery activity this month also included a single strike near Bracknell on Saturday 14th in evening during the torrential rain and hail that affected Romsey. There were more widespread thunderstorms in the Basingstoke and Farnborough areas moving over towards Heathrow Airport late on Sunday 15th. There was some hail at Guildford at 1714 from an isolated shower and 2254~2258 from the main activity which was much heavier further west and north.     

[Superstormuk]

17 hours ago, Robbie Garrett said:

Rather odd how you can get a Supercell in the winter and not much in the Summer. 

Yes, it is very interesting for this time of year. But, I guess all these Atlantic depressions bring a lot of instability and wind shear which really suits supercell formation. 

If you look at one of my previous posts, I think from either September or early October, I took a photo of a structure that looked (and probably was) mesocylonic, and that was on a coolish autumn day. 

Edit: Also, this winter (so far) has been quite mild, which has probably also helped. 

 

Edited December 22, 2019 by Superstormuk

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Mon 23 Dec 2019 - 05:59 UTC Tue 24 Dec 2019

ISSUED 20:32 UTC Sun 22 Dec 2019

ISSUED BY: Dan

Residual upper troughing will linger close to Scotland early on Monday, but this will generally fill and lift to the north with time. As such, showers / showery rain in western Scotland may produce an isolated lightning strike during the morning, but the risk will diminish with each passing hour.

Otherwise, the main focus will be later on Monday night associated with the approaching Atlantic upper trough. To the south of the main backbent occlusion, instability is expected to increase with several hundred J/kg CAPE. Increased forcing as the upper trough approaches from the west may lead to deep convection evolving over the Celtic Sea / S Ireland around midnight, this then quickly extending eastwards towards Wales / SW England during the early hours of Tuesday. 

Given the environment in place - marked mid-level dry intrusion, significant potential instability, strong shear, and reasonable CAPE - some well-organised convection is possible, perhaps even one or two low-topped supercells, which would be capable of producing sporadic lightning and strong gusts of wind. However, there is some uncertainty over the exact forecast evolution, and for now have refrained from introducing a SLGT.

http://convectiveweather.co.uk/forecast.php?date=2019-12-23

[Thunder and Lightning]

Has anyone else noticed the potential for significant storms tomorrow? It looks like a squall line or semi - discrete storm mode could affect the SW and S of England including Wales. Met Office thunderstorm warning for the early morning till midday.

[Zak M]

27 minutes ago, MetWeather said:

Has anyone else noticed the potential for significant storms tomorrow? It looks like a squall line or semi - discrete storm mode could affect the SW and S of England including Wales. Met Office thunderstorm warning for the early morning till midday.

Wouldn't call them significant. I've got a feeling that tomorrow is literally a repeat of what happened one October day this year when they issued an amber storm warning and there was literally not a storm in sight across the whole of the UK.

[Thunder and Lightning]

Oh I Just realised! You are the one who did that great storm YouTube video of the 27 August! I always try to find videos like that but they are only for the US. Sorry for going off-topic. Also I do think this is more of a situation than that time in October as that was an MCS that went of course, though these are storms which seem to be home grown.

[Zak M]

6 minutes ago, MetWeather said:

Oh I Just realised! You are the one who did that great storm YouTube video of the 27 August! I always try to find videos like that but they are only for the US. Sorry for going off-topic. Also I do think this is more of a situation than that time in October as that was an MCS that went of course, though these are storms which seem to be home grown.

Just seen the CW forecast that Summer Sun posted above. Looks like there is a decent chance for storms in St Georges Channel and the Bristol Channel.

And cheers, that indeed was me

[Thunder and Lightning]

Thunderstorm activity picking up now.

 

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Tue 24 Dec 2019 - 05:59 UTC Wed 25 Dec 2019

ISSUED 05:55 UTC Tue 24 Dec 2019

ISSUED BY: Dan

The main interest will be during Tuesday morning from the Celtic Sea / St Georges Channel across Wales and parts of SW England. A shortwave will move eastwards across these area, with deep convection likely to be present in an environment with several hundred J/kg CAPE, strong shear (albeit mostly uni-directional) and potential instability. This suggests that convection may become organised, with the potential for one or two low-topped supercells. Strong gusts of wind, hail up to 2.0cm in diameter, isolated tornadoes and some sporadic lightning is possible. Confidence is not particularly high on the coverage of lightning (which serves as the primary focus for our forecast maps), but a low-end SLGT has been issued to highlight the areas where lightning is most likely to occur, albeit rather sporadically. Some disruption may be possible locally.

In general, the intensity of convection is expected to weaken gradually towards late morning onwards as showers continue to push well inland across southern Britain. Thereafter, the focus for any additional lightning activity will be across northern and western Scotland, and NW Ireland, but even here the risk is considered very low.

http://www.convectiveweather.co.uk/forecast.php?date=2019-12-24

[Marcus_surfer]

No storms here as expected a rather pointless weather warning put out by the met office so far!

[ThundersnowDays]

Saw a distant flash of lightning earlier

[The4Seasons]

20 minutes ago, ThundersnowDays said:

Saw a distant flash of lightning earlier

We had a good storm in cowbridge vale of glamorgan with hail at around 7ish this morning. 1cm hail created a temporary thin covering over the ground. About 7 flashes and close bangs of thunder with gusty winds. Lasted about 30 mins. That was our brief white Christmas lol. Have a good one all

[chapmanslade]

5 hours ago, Marcus_surfer said:

No storms here as expected a rather pointless weather warning put out by the met office so far!

Speak for yourself - 5 or 6 good cracks of thunder this morning and pea sized hail at around 9.15.

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Thu 26 Dec 2019 - 05:59 UTC Fri 27 Dec 2019

ISSUED 23:41 UTC Wed 25 Dec 2019

ISSUED BY: Dan

As an upper trough disrupts, with one piece drifting eastwards across southern Britain on Boxing Day, scattered showers may develop behind the main frontal rain in an environment with a couple hundred J/kg CAPE. The majority of showers will be located within the base or axis of the trough, where shear is typically weaker, and so the poor phasing of CAPE and strong shear on the rear side of the trough does not bode well for much in the way of organisation and hence lightning prospects. Given restricted cloud depth and fairly weak instability, we do not anticipate much (if any) lightning activity.

http://convectiveweather.co.uk/forecast.php?date=2019-12-26

[Summer Sun]

Day 2 Convective Outlook

VALID 06:00 UTC Thu 02 Jan 2020 - 05:59 UTC Fri 03 Jan 2020

ISSUED 21:11 UTC Wed 01 Jan 2020

ISSUED BY: Dan

An active cold front will approach the Hebrides later on Thursday afternoon, with a sharp thermal gradient and wind veer. On the forward side of an approaching Atlantic upper trough, the environment will be strongly sheared. As a result, embedded line convection / LEWP seems likely within the main frontal precipitation, capable of producing squally bursts of rain and strong gusts of wind. Given strong low-level shear and weak CAPE, an isolated tornado may be possible. However, the risk of lighting is considered very low.

On Thursday night a cold airmass will advect over relatively warm seas, resulting in scattered showers across northern and western Scotland. As a result, isolated lightning strikes may occur - although the depth of convection is likely to be quite shallow in nature.

http://convectiveweather.co.uk/forecast.php?date=2020-01-02

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Wed 08 Jan 2020 - 05:59 UTC Thu 09 Jan 2020

ISSUED 09:01 UTC Wed 08 Jan 2020

ISSUED BY: Dan

Cool air aloft across Scotland on Wednesday will create an environment with a a couple hundred J/kg CAPE, with numerous showers affecting many northern and western parts but pushing well-inland on strong winds. One or two isolated lightning strikes may be possible, but the risk is rather low in any one location.

Overnight, a frontal zone will head northwards across England, Wales and Ireland, associated with a surface low drifting northeastwards towards the Irish Sea. Some pockets of marginal CAPE may exist within the warm sector / close to the cold front, and more especially behind the cold front as a marked mid-level dry intrusion (and associated steep mid-level lapse rates) spreads across the Irish Sea / western Britain during the early hours. As such, a few sporadic lightning strikes may be possible, but most areas will likely remain void of lightning.

http://convectiveweather.co.uk/forecast.php?date=2020-01-08

 

[Allseasons-Si]

There is quiet a bit of lightning out in the Irish sea

Lightning & Thunderstorms - United Kingdom, England, Scotland, Wales, Ireland

EN.BLITZORTUNG.ORG

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Blitzortung.org provides lightning and thunderstorm information in real time on maps for USA, United Kingdom, Australia, new Zealand, Europa, Africa, Asia and other Countries.

also a nasty looking squall line with it too

Meteociel.fr - Radar de précipitations pluie et neige - Royaume-Uni/Irlande

WWW.METEOCIEL.FR

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La météo en temps réel et prévisions météo pour la France, Observations météo, modèles numériques et logiciels météo (GFS, ECMWF, UKMO, GEM, AROME, ARPEGE, JMA)

[Zak M]

Lightning detected near Manchester