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Storms and Convective discussion - 28th July 2019 onwards

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The squall line just went through here. Was battered with strong winds and torrential rain. Felt like I was in a tornado!

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Day 1 Convective Outlook

VALID 06:00 UTC Tue 14 Jan 2020 - 05:59 UTC Wed 15 Jan 2020

ISSUED 08:37 UTC Tue 14 Jan 2020

ISSUED BY: Dan

Showers will persist across northwest Britain and northwest Ireland throughout Tuesday and Tuesday night, in an environment with steep mid-level lapse rates and a few hundred J/kg CAPE. As such, some occasional lightning strikes will be possible, although the coverage and frequency is probably not significant enough to warrant a SLGT. Nonetheless, some hail and strong gusts of wind are likely, with snow on modest hills.

Elsewhere a secondary surface low will run northeastwards across the Celtic and Irish Seas this afternoon, and across northern England early evening before exiting to the North Sea. The strongly-sheared environment will allow line convection to once again along the cold front, particularly Wales / SW England second half of the afternoon, extending across the Midlands later in the day. Given some weak CAPE in the vicinity, it is possible a few sporadic lightning strikes may occur with this feature, although the main focus will be squally bursts of rain and strong gusts of wind. Such setups can occasionally produce brief tornadoes, especially given strong shear in the lowest levels and any breaks in the line segments.

http://convectiveweather.co.uk/forecast.php?date=2020-01-14

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Day 2 Convective Outlook

VALID 06:00 UTC Thu 16 Jan 2020 - 05:59 UTC Fri 17 Jan 2020

ISSUED 20:58 UTC Wed 15 Jan 2020

ISSUED BY: Dan

The next Atlantic cyclone will gradually deepen as it tracks northeastwards close to the Hebrides during Thursday. Frontal precipitation will affect most parts of the British Isles at some point during this forecast period, with pockets of weak CAPE in places - as such, the odd isolated lightning strike cannot be ruled out. 

Later in the day, and more especially overnight, an upper trough will advance from the west, leading to increased instability and steepening mid-level lapse rates. Showers will affect many western areas, and later in the night southern areas also, capable of produce a few lightning strikes, hail and gusty winds.

http://convectiveweather.co.uk/forecast.php?date=2020-01-16

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3 hours ago, Kirkcaldy Weather said:

Anyone from Hampshire? p080ndz7.jpg

I’m about a mile away from where that was. Had a torrential downpour here at around 4am when reports say that happened so would fit in with that. No thunder with it though.

Spoke to someone who had been down there for a look and they said the damage was localised to about three houses but a fair amount of debris around mainly fences and roof tiles.

Edited by matt111

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4 hours ago, Kirkcaldy Weather said:

Anyone from Hampshire? 

p080ndz7.jpg
WWW.BBC.CO.UK

People living on the Hampshire coast woke to find damaged windows, fences and walls.

Local newspaper article here 

10911978
WWW.BOURNEMOUTHECHO.CO.UK

RESIDENTS were awoken in the middle of the night as a "tornado" left a trail of damage through their properties in the early hours.

 

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Day 2 Convective Outlook

VALID 06:00 UTC Sat 18 Jan 2020 - 05:59 UTC Sun 19 Jan 2020

ISSUED 17:15 UTC Fri 17 Jan 2020

ISSUED BY: Dan

Upper trough will gradually clear to the east of the British Isles on Saturday, but still enough cold air aloft to create an environment with very steep mid-level lapse rates and a few hundred J/kg CAPE. Showers will primarily affect northern and western Scotland during Saturday daytime, moving well-inland on the brisk northwesterly steering flow, but becoming increasingly isolated in nature by the afternoon as ridging builds across the British Isles. Convection and showers will persist over the North Sea through the evening and night hours, gradually clearing southeastwards - but perhaps passing close to the Norfolk coast for a time. Some sporadic lightning may be possible offshore with this activity.

http://convectiveweather.co.uk/forecast.php?date=2020-01-18

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21 hours ago, Summer Sun said:

Day 2 Convective Outlook

VALID 06:00 UTC Sat 18 Jan 2020 - 05:59 UTC Sun 19 Jan 2020

ISSUED 17:15 UTC Fri 17 Jan 2020

ISSUED BY: Dan

Upper trough will gradually clear to the east of the British Isles on Saturday, but still enough cold air aloft to create an environment with very steep mid-level lapse rates and a few hundred J/kg CAPE. Showers will primarily affect northern and western Scotland during Saturday daytime, moving well-inland on the brisk northwesterly steering flow, but becoming increasingly isolated in nature by the afternoon as ridging builds across the British Isles. Convection and showers will persist over the North Sea through the evening and night hours, gradually clearing southeastwards - but perhaps passing close to the Norfolk coast for a time. Some sporadic lightning may be possible offshore with this activity.

http://convectiveweather.co.uk/forecast.php?date=2020-01-18

Not convinced a lot of this happened today , apart from the odd shower skirting the NE edges of the Scottish mainland, The SE skirting showers seem so far between, it would be a wing and a prayer they make it to Norfolk..

Edited by Dorsetbred

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Day 2 Convective Outlook

VALID 06:00 UTC Wed 29 Jan 2020 - 05:59 UTC Thu 30 Jan 2020

ISSUED 21:21 UTC Tue 28 Jan 2020

ISSUED BY: Dan

Scattered showers will affect northwestern parts of Britain during Wednesday, but will gradually weaken with time as ridging continues to build from the west. Meanwhile, an Atlantic frontal system with several waves will bring rain to parts of Scotland throughout this forecast period, and there may well be scope for some sporadic lightning to occur late on Wednesday night (more especially on Thursday morning) embedded within areas of showery rain approaching western Scotland from the Atlantic.

http://convectiveweather.co.uk/forecast.php?date=2020-01-29

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Day 2 Convective Outlook

VALID 06:00 UTC Thu 30 Jan 2020 - 05:59 UTC Fri 31 Jan 2020

ISSUED 20:14 UTC Wed 29 Jan 2020

ISSUED BY: Dan

A sharpening minor shortwave will engage the frontal system affecting Scotland during Thursday morning. The resultant increase in instability traversing west to east may encourage a few sporadic lightning strikes to occur - more especially the Hebrides (if any does indeed occur). Elsewhere, a weakening pocket of showery rain will be approaching Isles of Scilly and SW England on Thursday morning, but the risk of any lightning is considered fairly low. Overnight, the next frontal system will cross Ireland, with weak elevated instability - but the risk of lightning with this feature is also considered very low.

http://convectiveweather.co.uk/forecast.php?date=2020-01-30

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Day 1 Convective Outlook

VALID 06:00 UTC Fri 31 Jan 2020 - 05:59 UTC Sat 01 Feb 2020

ISSUED 07:02 UTC Fri 31 Jan 2020

ISSUED BY: Dan

The odd isolated lightning strike may be possible from showery bursts of rain during Friday and Friday night, but it is likely most areas will remain void of any lightning.

http://convectiveweather.co.uk/forecast.php?date=2020-01-31

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Estofex have a warning out

Storm Forecast
Valid: Sat 08 Feb 2020 08:00 to Sun 09 Feb 2020 06:00 UTC
Issued: Sat 08 Feb 2020 08:37
Forecaster: PISTOTNIK

A level 1 is issued for sea waters NW of the British Isles for severe convective wind gusts.

SYNOPSIS and DISCUSSION

A long-wave ridge slowly shifts eastward across central Europe and Scandinavia. It is flanked by a highly amplified trough over far-eastern Europe and another trough over the British Isles. The latter gets flattened as warm air advection ahead of an intense jet streak over the North Atlantic sets in. Stormy conditions affect the sea area NW of the British Isles on the cold side of the frontal zone. Showers and isolated low-topped thunderstorms ahead of a travelling vorticity maximum may partly contribute to widespread severe wind gusts. Limiting factor is the low depth of instability and the low coverage of electrified convection.

http://www.estofex.org/cgi-bin/polygon/showforecast.cgi?text=yes&fcstfile=2020020906_202002080837_1_stormforecast.xml

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Day 1 Convective Outlook

VALID 06:00 UTC Sat 08 Feb 2020 - 05:59 UTC Sun 09 Feb 2020

ISSUED 06:40 UTC Sat 08 Feb 2020

ISSUED BY: Dan

A band of squally rain is expected to develop late on Saturday morning, eventually approaching NW Ireland and W Scotland during the afternoon, perhaps producing some sporadic lightning over the Atlantic but is expected to weaken (lightning-wise) as it moves inland. As such, have tentatively introduced a low-end SLGT, but the main focus will be offshore to the west of these areas. Nonetheless, damaging gusts of 70-80mph will be possible with this feature as it moves into the Outer Hebrides in particular. CAPE will be rather weak by landfall, and profiles rather saturated despite strong shear, and so lightning activity is a little questionable.

Showers will follow this feature across N + W Scotland, and may produce a few isolated lightning strikes during Saturday night close to the Northern Isles. Elsewhere, during the early hours of Sunday some squally features may develop over parts of Ireland, tracking eastwards. The setup is rather messy, with widespread dynamic rainfall but also pockets of convection, making it difficult to pinpoint specific areas where lightning may occur. The overall environment will yield up to 500 J/kg CAPE towards the end of the night, with very strong shear. Nonetheless, should any linear features develop, strong gusts of wind may occur and a tornado cannot be ruled out (in an environment already producing 40-55mph from the background wind field). If confidence improves, we may introduce an additional SLGT.

http://convectiveweather.co.uk/forecast.php?date=2020-02-08

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Day 2 Convective Outlook

VALID 06:00 UTC Sun 09 Feb 2020 - 05:59 UTC Mon 10 Feb 2020

ISSUED 21:47 UTC Sat 08 Feb 2020

ISSUED BY: Dan

A very active day of weather is expected across the British Isles, as a deep area of low pressure tracks eastwards close to northern Scotland. The strong north-south pressure gradient will lead to widespread strong winds, regardless of any additional convective component - and as such we are primarily interested in the additional damaging convective gusts / tornado potential on top of the pre-existing strong wind field (which is already covered in warnings by the Met Office and Met Éireann).

The environment will be strongly-sheared, with strong winds throughout the vertical, largely uni-directional. A strong LLJ (90-100mph winds at 850mb) will traverse and strengthen eastwards across England and Wales during Sunday, aiding advection of warm, moist low-level air immediately ahead of the surface cold front. A notable temperature/dewpoint gradient will exist across the cold front, with a slight wind veer. Model guidance suggests 100-300 J/kg CAPE will be available, while the forward motion of the front will aid in forced ascent. A remarkable 40-50kts of shear will exist in the lowest 1km!

All-in-all, the atmosphere will be primed for the development of one or more squall lines, fracturing at times to evolve into LEWPs. Some sporadic lightning is possible in places, hence the introduction of a SLGT. Transfer of high momentum air aloft down to the surface in downdrafts could lead to brief damaging straight-line wind gusts at ground level of 75-85mph (especially East Midlands into East Anglia). Such outflow combined with local topographical features could distort the low-level wind field sufficiently to generate bookend vortices and hence pose a risk of a few tornadoes, perhaps locally strong. A SVR has been introduced to highlight this risk. Of course, it is incredibly difficult to pinpoint exactly where this may occur, and the vast majority of the area will not see any tornadic activity - but should any fractures develop within squall lines, which seems likely, then this will increase the risk of a tornado on a local scale.

By mid-evening most squall line activity will have cleared to the English Channel and nearby Continent, leaving a rather more classic setup of cold air aloft and frequent showers piling into western areas, but moving well-inland on strong steering winds and more organised troughs in the flow. A few sporadic lightning strikes will therefore be possible on Sunday night, primarily over open waters and near exposed western coasts.

http://convectiveweather.co.uk/forecast.php?date=2020-02-09

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Some sferics showing up around the far north of Wales and the NW coast of England approaching Liverpool area. Looks like an interesting day today, especially by February standards, with an Estofex level 2, Convective Weather SLGT plus SVR and this storm forecast from Nick F.

I have never managed to capture a storm in February, maybe today. I won't be chasing though, not with widespread winds of 60-70mph. 

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Just travelling through the squall on the M25 West bound. Lightning looks to have died out for now. Conditions poor out here.

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Day 2 Convective Outlook

VALID 06:00 UTC Mon 10 Feb 2020 - 05:59 UTC Tue 11 Feb 2020

ISSUED 21:46 UTC Sun 09 Feb 2020

ISSUED BY: Dan

Strong west-northwesterly flow covers the British Isles throughout Monday, advecting markedly cold air from Arctic Canada across the Atlantic. This will create an environment with very steep mid-level lapse rates, especially from Monday evening onwards as the real cold air aloft arrives, yielding 300-600 J/kg CAPE in response to SSTs. As such, numerous showers will develop over open waters and plough inland on strong steering winds, merging to give longer spells of rain (and snow) at times as organised troughs and occlusions swing through in the flow.

The greatest risk of lightning will be over open waters and near western coasts, with an uptick in activity likely during Monday evening and night over parts of N / NW Ireland and W / SW / NW Scotland. Hail is likely in many of the showers, with snow on hills and increasingly to lower levels during the evening and night hours. Despite weaker instability and more limited convective depth across S Ireland / C + S Britain, the environment will be strongly sheared and hence favourable for low-topped supercells. Strong gusts of wind will accompany many of the showers, with gusts of 70-80mph possible along exposed western coasts (especially W Ireland).

http://convectiveweather.co.uk/forecast.php?date=2020-02-10

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Day 2 Convective Outlook

VALID 06:00 UTC Tue 11 Feb 2020 - 05:59 UTC Wed 12 Feb 2020

ISSUED 21:25 UTC Mon 10 Feb 2020

ISSUED BY: Dan

Strong west-northwesterly flow covers the British Isles with significantly cold air aloft, originating from Canada. This will result in an environment with very steep mid-level lapse rates and 300-700 J/kg CAPE. Consequently, numerous showers will develop over open waters and plough inland on strong steering winds, merging to give longer spells of rain (and snow) at times as organised troughs and occlusions swing through in the flow. The greatest risk of some sporadic lightning will be over open waters and near western coasts. Shear will be strongest across Ireland and central/southern Britain, which will aid in lightning potential despite more limited convective depth / weaker instability here. Some organisation of cells will be possible, with strong gusts of wind and perhaps scope for a low-topped supercell. Many of the showers will contain hail.

http://convectiveweather.co.uk/forecast.php?date=2020-02-11

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17 minutes ago, Another Kent clipper said:

2600 strikes today.  Bodes well for the rest of the year...

Now you've done it!

I managed to record 14 strikes from showers passing to my South. I did hear a very faint rumble from one around 2:30pm.

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Had 2 rumbles and flashes for the year here already one back in January and another yesterday hopefully a good sign as the year goes on make up for all the near misses last year

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Can add another flash/bang to that today. Very lively start to the year!

 

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Just had 2 large bangs of thunder followed by hail then snow. Its been a day of all sorts of weather today. 

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