Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Uk General Convective Discussion & Forecasts, 10th October 2012>


Jane Louise

Recommended Posts

Posted
  • Location: Cheltenham,Glos
  • Weather Preferences: Thunderstorms :D
  • Location: Cheltenham,Glos

Here's a brand new thread for Autumn onwards and there's even a little potential for something tomorrow folks. . smile.png

DISCUSSION

British Isles, France

A warm and moist maritime air mass is situated across the Atlantic west of the Bay of Biscay. This air mass is convectively mixed and is advected north-eastwards ahead of the approaching trough. Along the axis of warm air, a well-developed low-level trough is present and will move into France and the British Isles. At the surface, backing low-level winds are indicated by latest GFS model across southern France and the British Isles, leading to low-level convergence. A weak mid-level trough will also lead to some QG forcing.

Daytime heating will result in weak instability across France. Instability over the British Isles is questionable, but elevated CAPE is likely given the well-mixed air mass. Given the lift along the trough axis and low-level convergence, at lead weak CAPE is likely. Together with CAPE and forcing, low-level vertical wind shear is expected to be around 10 m/s in the lowest km and low-level hodographs are rather large across the British Isles. Current thinking is that tornadoes can develop in this environment. Given the weak instability, chance of tornadoes seems to be too low for a level 1 forecast. Stronger storms may also produce excessive precipitation. Otherwise, severe storms are not expected across the Birtish Isles and France.

http://www.estofex.org/

Link to comment
Share on other sites

Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Valid: 11/10/2012 00:00 - 12/10/2012 00:00

Headline: ... THERE IS A RISK OF THUNDERSTORMS FORECAST...

post-1052-0-11297900-1349906942_thumb.jp

Synopsis

A broad upper trough is in place over the N Atlantic to the W and NW of the UK, while an upper shortwave trough moving NE ahead of this long-wave trough approaches SW UK overnight - with associated surface low heading NNE up the Irish Sea tomorrow to be centred over Sern Scotland Thursday night. Cold front will move east across the UK during Thursday.

... S WALES, S ENGLAND, S MIDLANDS, E ANGLIA ...

Relatively warm and rather moist Tm air, with dew points reaching 14-15C, will advect north across Sern Britain on Thursday in a narrowing warm sector ahead of cold front moving in from the west during the afternoon. Some convection looks possible as the shortwave, forcing from cold front and falling pressure promote forced ascent of the moist air. So there is potential for a few isolated embedded storms before the cold front clears through. Deep layer shear will generally be rather weak, with jet stream still way to the west, though some moderate low-level shear is indicated. However, rather saturated profiles will mean lapse rates will not be particularly steep - so scope for severe weather will be limited. Though there is a risk of some torrential downpours developing, particularly towards SW UK, leading to the risk of localised flooding.

Also found here: http://www.netweathe...onvective;sess=

Link to comment
Share on other sites

Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Valid: 12/10/2012 00:00 - 13/10/2012 06:00

Headline: ... THERE IS A RISK OF THUNDERSTORMS FORECAST...

post-1052-0-71427900-1349993428_thumb.jp

Synopsis

Upper trough to the west of the British Isles Thursday night will become negatively-tilted as it digs SE across Ireland and Sern UK during Friday morning. Slow-moving surface low will be centred over Ern Scotland at 12z Friday, with quasi-stationary front straddling N Scotland, to the south - an unstable Werly flow will be in place.

... IRELAND, S WALES and S ENGLAND ...

Unstable rPm airmass will be in place across Ireland and southern Britain. 500mb temperatures AOB -25C will spread SE across Ireland and Sern Britain through Friday morning, which will create steep lapse rates - particularly across southern and western coastal areas where we have the influence of relatively warm sea surface temperatures. Heavy showers and a few thunderstorms will spread inland across southern and western coastal counties through the day, bringing a risk of hail and locally torrential downpours. Convection will be enhanced by shortwave troughs in the westerly flow, as progressively colder air spreads SE aloft. Although organised severe weather is not anticipated, like Thursday, there is a risk of localised flooding. Risk of showers and isolated storms may continue near southern and western coasts Friday night.

Can also be found here: http://www.netweather.tv/index.cgi?action=convective;sess=

Link to comment
Share on other sites

Posted
  • Location: Stanwell(south side of Heathrow Ap)
  • Weather Preferences: Thunderstorms, squally fronts, snow, frost, very mild if no snow or frost
  • Location: Stanwell(south side of Heathrow Ap)

Looks as though we could get some interesting weather today(Thursday)an active system steams across bringing with it a lot of rainfall, and the risk of thunder and lightning, perhaps even thunderstorms.

post-11361-0-04287000-1349915829_thumb.g

The map shows everywhere is going to get very wet, with local flooding for many areas and the most prolonged and heavy rainfall flooding rivers, this weather system bringing yet more disruption.

Here is a recent radar image:

2115.gif

Below is NAE 1800-0000hrs rainfall

12101200_2_1118.gif

If we look at the 0000hrs-0600hrs it shows the heavy and prolonged rainfall over Northern England and Scotland

12101206_2_1118.gif

Through Friday the focus for the most heavy and prolonged rain is on Scotland:

Next is the 0600-1200hrs precipitation image, Eastern areas of Scotland are likely to recieve a significant amount of rain:

12101212_2_1118.gif

Also keep watch on some heavy downpours across the Southwest, although over southern parts could get them but the heaviest likely in the SW

Last of all taking a look at the accumulated precipitation up to 3am saturday, this shows large totals of rain for Northern and Eastern Scotland.

12101306_2_1118.gif

(CHARTS - NAE 18Z)

ESS

Edited by ElectricSnowStorm
Link to comment
Share on other sites

Posted
  • Location: Stanwell(south side of Heathrow Ap)
  • Weather Preferences: Thunderstorms, squally fronts, snow, frost, very mild if no snow or frost
  • Location: Stanwell(south side of Heathrow Ap)

Want to add in the the surface pressure and the 500/1000hpa chart for Friday(GFS 18z), much colder upper temperatures through friday, and much cooler on the surface to, with a gusty westerly bringing heavy thundery showers/storms across southern/western areas,

1200hrs-Thickness 500/1000hpa:

12101212_2_1118.gif

1500hrs-Surface pressure below:

12101215_2_1118.gif

ESS

Edited by ElectricSnowStorm
Link to comment
Share on other sites

Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Very quiet in this thread these days.

Some nice convective skies to the south of London late this afternoon, some sferics across Sussex too.

post-1052-0-53935700-1350055413_thumb.jp

Been clipped by a few light showers here in south London

Edited by Nick F
Link to comment
Share on other sites

Posted
  • Location: Warminster, Wiltshire
  • Location: Warminster, Wiltshire

You say it's quiet Nick but there hasn't been convective activity for what seems like ages until today.

So good to have a clean convective day with beautiful CB cloudscapes and this afternoon there's been some lightning inland in the West Country

now that the showers have survived further inland than throughout the morning. Just a few sharp showers in my town though.

Tomorrow should be a similarly good cloud watching day and I guess Sunday could be too should the troublesome LOW be further South rather than

providing high cloud acrosss the South.

Link to comment
Share on other sites

Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Three rumbles of thunder here an hour ago!with blue sunny sky and no rain .smile.png

Who's going to run the No Storms Club now, then?

Link to comment
Share on other sites

Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

You say it's quiet Nick but there hasn't been convective activity for what seems like ages until today.

Maybe not for many areas, but we saw some torrential convective downpours across SW England yesterday, which caused flash floods down the streets on Clovelly, north Devon. Today, sharp showers and a few storms are more widespread across the south.

Link to comment
Share on other sites

Posted
  • Location: Warminster, Wiltshire
  • Location: Warminster, Wiltshire

Maybe not for many areas, but we saw some torrential convective downpours across SW England yesterday, which caused flash floods down the streets on Clovelly, north Devon. Today, sharp showers and a few storms are more widespread across the south.

True re yesterday Nick, but I guess if no NW members are in the area then we won't get the posts.

To add to what I said about this area today, my wife reported settling hail around 14.30 a few miles North of Salisbury which the children in her preimary school class thought was snow!

Edited by Andy Bown
Link to comment
Share on other sites

Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

a possibility of some rumbles of thunder if current shower activity in bristol channel keeps on moving east .would not be surprised to see a cover of hail . trough slowing a little and nice looking sky to my west of south west cheers .

Link to comment
Share on other sites

Posted
  • Location: Home near Sellindge, 80m/250feet, 5miles from Coast
  • Weather Preferences: Severe Storms and Snow
  • Location: Home near Sellindge, 80m/250feet, 5miles from Coast

Epic :D, i saw a thunderstorm way out to sea on my walk home tonight... Flashing up the tiny storm in the distance

Link to comment
Share on other sites

Posted
  • Location: Carmarthenshire
  • Location: Carmarthenshire

Some beefy hail showers here in west Wales this afternoon. Left work at lunchtime in sunshine only to be pelted by hail a couple of minutes later without an umbrella or hood to hide under - ouch!

Link to comment
Share on other sites

Posted
  • Location: Dead Centre of the Vale of Clwyd
  • Weather Preferences: Cold Sancerre.
  • Location: Dead Centre of the Vale of Clwyd

Just watched about 7 or 8 IC off the coast of N Wales whilst out with the wuffers about 20 mins ago. Looking at the radar could be the beefy showers off N Anglesey.

Link to comment
Share on other sites

Posted
  • Location: Rochester, Kent
  • Location: Rochester, Kent

Pea sized hail observed in Rochester - was on the leading edge of a cell and soon turned to rain

post-5986-0-27707900-1350128324_thumb.gi

This is about the tenth time that severe weather has been observer regardless of other factors in the skew-t, with the only factor that seems to be predictive of this sort of weather is the Totals totals statistic. Anecdotal, for sure, but interesting nevertheless, and that statistic is expected to rise until this evening. Potentially, more on the way :)

Edited by Boar Wrinklestorm
Link to comment
Share on other sites

Posted
  • Location: Stoke Gifford, Bristol
  • Weather Preferences: Snow, Thunderstorms, Heat Waves, Tornadoes.
  • Location: Stoke Gifford, Bristol

Not seen hail for a long time but had 2 hail showers today which was cool and lots of pavements in Bradley Stoke covered in ice, nice! Clouds look awesome today.

Link to comment
Share on other sites

Posted
  • Location: Warminster, Wiltshire
  • Location: Warminster, Wiltshire

Radar indicating a fairly potent hailstorm NE of Westbury/SE of Devizes, Wilts currently. Quite a few showers dotted about the country. Shortwave trough in cold air aloft assisting in forcing of marginally unstable air mass.

Lovely to see this area get a mention, certainly some spectacular CBs today and a lot of hail showers apparantly, although I was out in Hampshire all afternoon with only a few heavy rain showers.

Link to comment
Share on other sites

Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

Quite a potent cold front just gone through here in the outskirts of Madrid with heavy rain and squally winds. Also had lightning and thunder after it had passed.

Link to comment
Share on other sites

Posted
  • Location: Portishead, North Somerset
  • Weather Preferences: Severe
  • Location: Portishead, North Somerset

Small funnel cloud seen about 5+ miles off Perranporth just after midday yesterday. I think I caught the back end of it as it faded within a minute of me spotting it so I don't know whether it was larger at any point - must check the beeb to see if it was reported. I took some video with phone. If the resolution is decent enough I will upload it to Youtube with my others.

I followed lots of interesting weather for approx 3 hrs yesterday, from Penzance to Bristol, but nothing else of note was witnessed.

Link to comment
Share on other sites

Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

We had a very potent shower at 4.30 am this morning ,i would say torrential for 5 min ,then crystal clear and it felt very cold ,must be some low temp mixed in with this air stream .gone dark now with some action in bristol channel .rest of the week looks pretty disturbed ,with some flooding issues in quite a few locations . some embedded troughs could produce some action .on saturday afternoon we had a spectacular hail storm ,very localised with two good rumbles and some gusty winds .cheers .

Link to comment
Share on other sites

Posted
  • Location: BRISTOL
  • Location: BRISTOL

A very good weekend for cloud watching here,lots of Tcu Cb's and 6 Anvils spotted,North Bristol battered by hail yet here in South Bristol it stayed dry and sunny,Don't think I will see anymore thunderstorms this year so roll 2013

Link to comment
Share on other sites

Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

A very good weekend for cloud watching here,lots of Tcu Cb's and 6 Anvils spotted,North Bristol battered by hail yet here in South Bristol it stayed dry and sunny,Don't think I will see anymore thunderstorms this year so roll 2013

Don't give up yet haha! In November 2009 there were 4. :)

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
  • UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-29 07:13:16 Valid: 29/03/2024 0600 - 30/03/2024 0600 THUNDERSTORM WATCH - FRI 29 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather

    Difficult travel conditions as the Easter break begins

    Low Nelson is throwing wind and rain at the UK before it impacts mainland Spain at Easter. Wild condtions in the English Channel, and more rain and lightning here on Thursday. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-28 09:16:06 Valid: 28/03/2024 0800 - 29/03/2024 0600 SEVERE THUNDERSTORM WATCH - THURS 28 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather
×
×
  • Create New...