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Storms and Convective discussion - 10th April 2020 onwards


Supacell

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London
1 minute ago, Ben Sainsbury said:

A positive run by the EURO4 12z and is supportive of the UKV & NMM so far. Initiation looks to take place from around 10am from Reading eastwards.

Despite there being an eastward shift in most of the models it is definitely a positive sign that the higher resolution models of EURO4, NMM and UKV all show thundery activity on Thursday. I think if the AROME also shows a similar scenario once it comes into view then I can definitely have more confidence. EURO4 12z below:

1.thumb.png.960902c35fc38d6860cb626f1111f2e7.png2.thumb.png.717cc2dfd59fcde5c38fb3da0f7a063b.png

Great to see! Contradicting what I just said, there does seem to be a trend of less elevated convection within some models. 

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Posted
  • Location: Thorley, west Isle of Wight
  • Weather Preferences: Spanish plumes & stormy winters. Facebook @ Lance's Lightning Shots
  • Location: Thorley, west Isle of Wight
3 minutes ago, Ben Sainsbury said:

A positive run by the EURO4 12z and is supportive of the UKV & NMM so far. Initiation looks to take place from around 10am from Reading eastwards.

Despite there being an eastward shift in most of the models it is definitely a positive sign that the higher resolution models of EURO4, NMM and UKV all show thundery activity on Thursday. I think if the AROME also shows a similar scenario once it comes into view then I can definitely have more confidence. EURO4 12z below:

1.thumb.png.960902c35fc38d6860cb626f1111f2e7.png2.thumb.png.717cc2dfd59fcde5c38fb3da0f7a063b.png

I'd take that one right now. I wouldn't even have to travel that far to see something

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Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol
1 minute ago, Thunder and Lightning said:

Great to see! Contradicting what I just said, there does seem to be a trend of less elevated convection within some models. 

No-one can be sure yet what's going to happen so every opinion is valid! The trend of less elevated convection is something that is talked about by Tony Gilbert over on UKWW. He said that the less elevated convection during early morning then the higher the risk of severe/marginally severe surface based storms later in the day so.

Interesting read:

WWW.UKWEATHERWORLD.CO.UK

Slight Risk of Severe Thunderstorms Central and Eastern UK 06z-18z Ironically initially started this...

 

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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset

Something I have noticed on the UKV, compared to a few days ago... cloud moves in very quickly, and covers much of the country before mid-morning. That could be a hinderance if it turns out to be correct.

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London
1 minute ago, Mapantz said:

Something I have noticed on the UKV, compared to a few days ago... cloud moves in very quickly, and covers much of the country before mid-morning. That could be a hinderance if it turns out to be correct.

Another thing I have noticed is that recently the UKV has been tending to overdo cloud. I'm not sure if it will happen but something was noticing last week

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Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

Absolutely balmy and gorgeous evening - sat in the garden after eating some whopping great big T-bone steaks. Sensational! Feels as if we’re on the verge of a plume type evolution...make of that what you will lol

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Posted
  • Location: Dorset
  • Weather Preferences: warehamwx.co.uk
  • Location: Dorset
1 minute ago, Thunder and Lightning said:

Another thing I have noticed is that recently the UKV has been tending to overdo cloud. I'm not sure if it will happen but something was noticing last week

Well, there's a frontal system moving in from the West, so it is inevitable that it will turn cloudy for many, and then sunshine on the back-side of it.

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Posted
  • Location: Woodchurch, Kent.
  • Weather Preferences: Storm, drizzle
  • Location: Woodchurch, Kent.
1 hour ago, viking_smb said:

yep, totally agree, think xpander just gets excited.

i was saying how it doesn't sound good 

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Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)

Stav’s evening BBC forecast suggest that Beeb thinking later arrival of trough with highs again of 26/27C....

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12 minutes ago, Harry said:

Absolutely balmy and gorgeous evening - sat in the garden after eating some whopping great big T-bone steaks. Sensational! Feels as if we’re on the verge of a plume type evolution...make of that what you will lol

I was just thinking the same thing, there's a few clouds materialised out of nowhere in the south East

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Posted
  • Location: Bristol
  • Weather Preferences: Thunderstorms and Snowstorms
  • Location: Bristol

Oh WOW! An extraordinary difference on the UKV 15z and whilst first glance looks impressive it's much worse than the 12z regarding severe potential. Trough seems to pass through much quicker and as a result we actually have an eruption of intense elevated storms across CS England towards the SE but a much lower risk of surface based convection with very small SB Cape values.

CAPE.thumb.png.fe41f2bfc8725565a54c0c88d5596f40.pngPrecip.thumb.png.e421ba8f73da52bd1c960f9a0545cb59.png

 

Edited by Ben Sainsbury
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Posted
  • Location: Godalming
  • Weather Preferences: Plumes and streamers
  • Location: Godalming
16 minutes ago, Ben Sainsbury said:

Oh WOW! An extraordinary difference on the UKV 15z and whilst first glance looks impressive it's much worse than the 12z regarding severe potential. Trough seems to pass through much quicker and as a result we actually have an eruption of intense elevated storms across CS England towards the SE but a much lower risk of surface based convection with very small SB Cape values.

CAPE.thumb.png.fe41f2bfc8725565a54c0c88d5596f40.pngPrecip.thumb.png.e421ba8f73da52bd1c960f9a0545cb59.png

 

I’ll buy this

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Posted
  • Location: Bexley (home), C London (work)
  • Weather Preferences: Thunderstorms
  • Location: Bexley (home), C London (work)
35 minutes ago, Ben Sainsbury said:

Oh WOW! An extraordinary difference on the UKV 15z and whilst first glance looks impressive it's much worse than the 12z regarding severe potential. Trough seems to pass through much quicker and as a result we actually have an eruption of intense elevated storms across CS England towards the SE but a much lower risk of surface based convection with very small SB Cape values.

CAPE.thumb.png.fe41f2bfc8725565a54c0c88d5596f40.pngPrecip.thumb.png.e421ba8f73da52bd1c960f9a0545cb59.png

 

Imby alert - bank bank bank bank bank bank bank!!!!!

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Posted
  • Location: NW London
  • Weather Preferences: Convective Weather and Snow
  • Location: NW London

Well at least I'm in the CW day 3 slight, so no complaining about that! Again, I have never seen a Day 3 Slight from CW. Hopefully a sign of things to come...

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Day 3 Convective Outlook

VALID 06:00 UTC Thu 21 May 2020 - 05:59 UTC Fri 22 May 2020

ISSUED 19:53 UTC Tue 19 May 2020

ISSUED BY: Dan

Upper ridge over the British Isles will retreat eastwards on Thursday morning as a pronounced negatively-tilted shortwave approaches from the southwest. At 06z the trough axis is expected to be located north Wales-Dorset, shifting northeast to Cumbria-East Sussex by 09z and exited to the North Sea by 12z. In its wake, substantial subsidence is anticipated as a new upper ridge builds from the west. Ahead of this trough, a plume of high Theta-W will be advected from France into Cen S / SE England, and this will provide the focus for a developing elevated instability axis as the mid-levels cool and moisten due to the approaching trough.

Some concerns exist with:

(a) the timing of the shortwave, model guidance continues to trend towards a faster arrival and this ultimately results in an ever-smaller window of opportunity for destabilisation over the British Isles before clearing eastwards

(b) mid-level moisture (or lack of), especially in the 700-850mb layer which may inhibit elevated thunderstorm development in places

Model guidance varies in both of these aspects, and this casts some uncertainty over how widespread deep convection will be. Regardless, it seems plausible at least scattered elevated showers and thunderstorms will develop during Thursday morning across East Anglia and SE England, drifting northeastwards with time. Some reasonable speed shear is possible on the forward side of the upper trough, and this may aid organisation of elevated thunderstorms into a small MCS - but the bulk of any lightning activity will be located on the eastern flank of such a complex where instability will be greatest (600-1,000 J/kg MLCAPE). Given the thermodynamic and kinematic environment, lightning could be fairly frequent at times and there is scope for hail up to 2cm in diameter from the strongest cells.

By mid-afternoon most activity is expected to have cleared to the North Sea, and given subsided profiles and potentially limited surface heating (due to earlier cloud cover) it is unlikely any surface-based convection will be able to develop. That said, we cannot rule out the potential for a tail-end cell to become rooted within the boundary layer if sufficient surface heating can occur immediately ahead of any elevated convection, especially considering any outflow and/or sea breeze boundaries that may exist to aid in forced ascent - but in general this is treated as a fairly low likelihood for now.

A SLGT has been introduced where lightning is most likely to occur, but this may be extended in future updates. Additional LOW threat levels may also be introduced elsewhere in the British Isles (such as E / NE Scotland) once the convective potential becomes a little clearer nearer the event.

http://convectiveweather.co.uk/forecast.php?date=2020-05-21

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Posted
  • Location: Benson, Oxfordshire
  • Location: Benson, Oxfordshire
1 hour ago, Ben Sainsbury said:

Oh WOW! An extraordinary difference on the UKV 15z and whilst first glance looks impressive it's much worse than the 12z regarding severe potential. Trough seems to pass through much quicker and as a result we actually have an eruption of intense elevated storms across CS England towards the SE but a much lower risk of surface based convection with very small SB Cape values.

CAPE.thumb.png.fe41f2bfc8725565a54c0c88d5596f40.pngPrecip.thumb.png.e421ba8f73da52bd1c960f9a0545cb59.png

 

I'll bank this thank you very much!

Now, if only initiation could shift a little further west and any cloud cover bog off....

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Posted
  • Location: King’s Lynn, Norfolk.
  • Weather Preferences: Hot and Thundery, Cold and Snowy
  • Location: King’s Lynn, Norfolk.
2 hours ago, Mapantz said:

Something I have noticed on the UKV, compared to a few days ago... cloud moves in very quickly, and covers much of the country before mid-morning. That could be a hinderance if it turns out to be correct.

It’s going to be very touch and go. A fast paced pattern with a limited window of opportunity. It may well have to be an early night tomorrow, and up at the crack of dawn with the birds I think! 

A drive as far as Essex is now looking probable for me. 

Edited by East_England_Stormchaser91
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Posted
  • Location: Wimbledon,SW London
  • Location: Wimbledon,SW London

One or two thundery showers over Norfolk early Thursday afternoon and that will be our lot. Happens every time. 

Cloudy elsewhere in the SE with patchy light rain. No storms unfortunately. 

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Posted
  • Location: Bedfordshire
  • Weather Preferences: Thunderstorms, plumes, snow, severe weather
  • Location: Bedfordshire

Lost all my hope for Thursday now 

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Posted
  • Location: Barton on Sea, Hampshire
  • Weather Preferences: Snowy winter, warm/hot summer with the odd storm thrown in
  • Location: Barton on Sea, Hampshire
3 minutes ago, Zak M said:

Lost all my hope for Thursday now 

If the UKV is anything to go by then I haven't :spiteful:

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Posted
  • Location: Barton on Sea, Hampshire
  • Weather Preferences: Snowy winter, warm/hot summer with the odd storm thrown in
  • Location: Barton on Sea, Hampshire
13 minutes ago, Mitch perrott said:

BBC weather seems to be making a bold forcast for me on Thursday ^-^

Screenshot_2020-05-19-21-46-17.png

That app always seems keen to forecast thunderstorms

Edited by matt111
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