Storm & Convective Discussion - 1 September 2015 onwards

[Flash Elvis]

Well the rain arrived!!!!

[Flash bang flash bang etc]

Anyone still watching the radar and hoping for UK sferics should check out this chart:

[SnowBear]

I think I seem to remember reading thunderstorms "could" develop. Not will do.

[Flash bang flash bang etc]

I think the BBC and most other UK-based forecasting outfits tend to go for the slightly higher-end risk in their forecasts, ie. a day most likely to have small and isolated thundery showers is likely to be forecast as 'possible thunderstorms' and even a slight risk of severe weather is usually accompanied by a 'chance of super cellular storms' tag line.

I guess it could be that I don't consider a 'thunderstorm' to be just a few flashes and bangs (hence I don't even consider my name to be a true thunderstorm). A proper thunderstorm should have far more activity than that, but I think UK forecasters tend to play-up the potential - and we all know it generally works the other way round in this part of the world ;-)

Not a dig at forecasters I hope you understand, more an observation I've made. It's open to interpretation of course :-D

Edited September 16, 2015 by Flash bang flash bang etc

[Supacell]

I mentioned a couple of days ago the disturbed clouds not far from Melton Mowbray, very near the village of Frisby. This thunderstorm that went on to produce a tornado near to Old Dalby just 2-3 miles further north. This is a speeded up video of the storm as it approached.

 

[snowrye]

Even estofex issued a level 2 alert for the south east and northern france

[snowrye]

Just seen on facebook that reed timmer has posted about a tornado in northern france this afternoon

[NO LONGER POSTING]

"potentially" some thunderstorms for the south tomorrow?

 

 

 

 

EURO4 also agrees but also something for tonight to..

 

 

 

 

 

Edited September 17, 2015 by Surrey

[Flash bang flash bang etc]

"potentially" some thunderstorms for the south tomorrow?

 

 

 

 

EURO4 also agrees but also something for tonight to..

 

 

 

 

 

Ooh - looks quite ripe...

Should I be planning a little trip down to the south coast later this evening then?

[NO LONGER POSTING]

Ooh - looks quite ripe...

Should I be planning a little trip down to the south coast later this evening then?

 

Could do..

 

Overnight, the focus for any lightning activity shifts to SW Scotland then NW England / N Wales, while a new round of convection will develop over the English Channel and run into parts of SE England through the early hours. There could be some small hail in any stronger cells, and the potential for some brief funnels/spouts, especially along southern coastal counties overnight as LLS increase a little.

 

It's tomorrow though that has better chance of a storm

[Sprites]

Ooh - looks quite ripe...

Should I be planning a little trip down to the south coast later this evening then?

NNNNOOOOOO!!!!!!

[NO LONGER POSTING]

Ooh - looks quite ripe...

Should I be planning a little trip down to the south coast later this evening then?

 

Although the risk is marginal :/

 

NNNNOOOOOO!!!!!!

 

 

Deffo a Jinx! 

[Nouska]

Just seen on facebook that reed timmer has posted about a tornado in northern france this afternoon

 

There have been four tornadoes in the last week, first one with full report and video.

 

http://www.keraunos.org/actualites/faits-marquants/2015/tornade-saint-bonnet-sur-gironde-13-septembre-2015-poitou-charentes-mirambeau-outbreak.html

 

 

Pictures of the one on the 16th

 

http://www.keraunos.org/actualites/fil-infos/2015/septembre/tornade-charente-maritime-sennac-matha-chaniers-migron-16-septembre-2015.html

Edited September 17, 2015 by Nouska

[Nick F]

CONVECTIVE OUTLOOK LATE THURS 17TH & FRIDAY 18TH SEPTEMBER

 

 

Issued: 17-09-2015 18z

Valid: 17/09/2015 1800z to 19/09/2015 0000z

 

Synopsis

Long-wave upper trough continues to edge east across much of northern and western Europe during the forecast period (18z Thurs - 00z Sat), with an upper ridge building in behind across Ireland and eastern Atlantic with a ridge to the east of the trough extending NE across SE Europe towards NW Russia. A surface low/trough near the Isle of Man at 00z Friday moves SE to be over SE England early afternoon before clearing later in the evening. Instability will develop across western areas from early Friday morning and later southern areas in association with this low/trough moving SE.

 

... SW SCOTLAND, N. IRELAND, NW ENGLAND, N WALES ...

 

A mid-level cold pool shown on 500mb charts moving SE tonight across the above areas will create steep lapse rates over seasonal warm SSTs, which combined with lift created by surface low/trough moving east with the upper trough, will support a cluster of heavy showers and perhaps isolated storms spreading SE from as early as this evening. Lack of diurnal heating and weak wind shear will mean severe weather is unlikely. Showers/storms may produce small hail, gusty winds and minor localised flooding.

 

... S WALES, S ENGLAND ...

 

Heavy showers and isolated thunderstorms are possible across the south coast of England tonight. Otherwise, mid-level cold pool, mentioned above, will continue SE towards SE UK during Friday. Surface heating during the day will create a few 100 j/kg CAPE across the above areas where moisture will be highest towards coasts as the cold pool arrives aloft steepening lapse rates. As a result, heavy showers and isolated to scattered thunderstorms will develop. Deep layer will be fairly weak with pool of instability moving east across the above areas during the day, so no organised severe weather is anticipated. Stronger cells may produce hail given steep lapse rates/cold air aloft, also there is a risk of localised flooding. With light winds aloft and surface convergence along surface trough axis moving SE, funnel clouds or even one or two brief/weak tornadoes/waterspouts can't be ruled out - particularly but exclusively near coasts with more buoyant updrafts created by warm SSTs.

 

Issued by Nick Finnis for Netweather

Edited September 17, 2015 by Nick F

[Flash bang flash bang etc]

Sounds rubbish - I'm going to hide under the duvet until summer comes back :-D

[Gordon Webb]

 

CONVECTIVE OUTLOOK LATE THURS 17TH & FRIDAY 18TH SEPTEMBER

 

convmap_180915.png

 

Issued: 17-09-2015 18z

Valid: 17/09/2015 1800z to 19/09/2015 0000z

 

Synopsis

Long-wave upper trough continues to edge east across much of northern and western Europe during the forecast period (18z Thurs - 00z Sat), with an upper ridge building in behind across Ireland and eastern Atlantic with a ridge to the east of the trough extending NE across SE Europe towards NW Russia. A surface low/trough near the Isle of Man at 00z Friday moves SE to be over SE England early afternoon before clearing later in the evening. Instability will develop across western areas from early Friday morning and later southern areas in association with this low/trough moving SE.

 

... SW SCOTLAND, N. IRELAND, NW ENGLAND, N WALES ...

 

A mid-level cold pool shown on 500mb charts moving SE tonight across the above areas will create steep lapse rates over seasonal warm SSTs, which combined with lift created by surface low/trough moving east with the upper trough, will support a cluster of heavy showers and perhaps isolated storms spreading SE from as early as this evening. Lack of diurnal heating and weak wind shear will mean severe weather is unlikely. Showers/storms may produce small hail, gusty winds and minor localised flooding.

 

... S WALES, S ENGLAND ...

 

Mid-level cold pool, mentioned above, will continue SE towards SE UK during Friday. Surface heating during the day will create a few 100 j/kg CAPE across the above areas where moisture will be highest towards coasts as the cold pool arrives aloft steepening lapse rates. As a result, heavy showers and isolated to scattered thunderstorms will develop. Deep layer will be fairly weak with pool of instability moving east across the above areas during the day, so no organised severe weather is anticipated. Stronger cells may produce hail given steep lapse rates/cold air aloft, also there is a risk of localised flooding. With light winds aloft and surface convergence along surface trough axis moving SE, funnel clouds or even one or two brief/weak tornadoes/waterspouts can't be ruled out - particularly but exclusively near coasts with more buoyant updrafts created by warm SSTs.

 

Issued by Nick Finnis for Netweather

 

 

would you believe it , It seems I might be out of luck tonight and possibly tomorrow I'm distraught I really am NOT

[Stormyking]

Lightning has jsut been spotted by my mate and some others jsut off th wst coast of the island, tonight is looking very interesting

[Winter Cold]

Should I expect much tonight? Forecast is for heavy and possibly thundery showers pushing through.....

 

Can see things developing nicely off the east coast of Ireland at the moment...

[Costa Del Fal]

Had a shower in woolacombe not long ago. Was sitting inside but did notice a flash which came from outside. Possibly was lightning.

[Stormyking]

Well there is no doubt that the weather seems exciting this Evening but I think this is taking too far with these cumulus.

 

Sorry I had to share this haha, took this off my iphone

 

[Flash bang flash bang etc]

Well there is no doubt that the weather seems exciting this Evening but I think this is taking too far with these cumulus.

 

Sorry I had to share this haha, took this off my iphone

 

They look like ball clouds mate...

[Mokidugway]

Gonadanimbus ????.

[Thunderbolt_]

More like phallonimbus.

[Convective]

Nice cumulus testiculous there, Stormyking.

 

Lightning detected around here. Can't see much outside, very overcast and heavy bursts of rain now and then.

[Mokidugway]

Nice cumulus testiculous there, Stormyking.

 

Lightning detected around here. Can't see much outside, very overcast and heavy bursts of rain now and then.

certainly a nice pilus belendus :0...