Convective/Storm Discussion

[Paul Sherman]

The action area seems to be about 35-50 Miles offshore, maybe due to the warm SST's at this time of year, would certainly give it another 90 minutes before deciding wether more form or to jack it in. Wish I was more on the ball with this today as I most probably would have picked a spot and got some pictures, looks like the clean air CG variety Storms which are oh so rare in the Uk!

Paul S

[Geordiesnow]

I was quite astonished and bemused when the attractive lady doing the BBC SE News weather about 5 mins ago said that there'll be a few light showers around this evening!!! Did she look at the radar in the last few hours ... lol. Michael Fish, who does SE News sometimes, wouldn't have have omitted what's going on outside?

Are those forecasts to be not pre-recorded Nick at that time? They are for up here.

Good to hear these unexpected storms in the SE, hope you all enjoy them.

[Nick F]

Are those forecasts to be not pre-recorded Nick at that time? They are for up here.

Good to hear these unexpected storms in the SE, hope you all enjoy them.

Aye, you could be right?

Line of showers forming to the south of me now, but don't look to have the same energy as further east.

[Tommyboy2007]

The action area seems to be about 35-50 Miles offshore, maybe due to the warm SST's at this time of year, would certainly give it another 90 minutes before deciding wether more form or to jack it in. Wish I was more on the ball with this today as I most probably would have picked a spot and got some pictures, looks like the clean air CG variety Storms which are oh so rare in the Uk!

Paul S

Yeah, the kind that would look great on a time lapse video. There seems to be some forcing for the convection moving east, contra to the direction of the steering winds looking at sat animation. I'm holding my breath and am ready to run.

[Azores Hi]

Aye, you could be right?

Line of showers forming to the south of me now, but don't look to have the same energy as further east.

Nazaneen definately looked like she was going clubbing on the 6:30 news!

[Tommyboy2007]

Look at the little cell just popped up to the east of the IOW. It looks as if it could be intense. Please !!

No, on second thoughts forget it. 10 55 radar shows that its stopped.

Edited October 22, 2009 by Tommyboy2007

[maidstone weather]

Well I think I've now worked out that it is me that has the storm shield, not the southeast, and it follows me wherever I go.

Thumbs up to Harry though, for dreams can come true :)

[Thundery wintry showers]

The storm shield will have to be pretty impressive to hold out over UEA, considering how thundery the last two summers have been here. April 2008 4 thunder-days, August 2008 6 thunder-days, July 2009 7 thunder-days. I used to feel I had a storm shield back in the early to mid 2000s but it has caved in recently, especially after going to Norwich.

The storms over the SE were somewhat unexpected, I hadn't even been checking the radar for a while.

[Neilsouth]

I can see these huge anvils out in the channel , not convective but good nonetheless

[Coast]

Yep, saw those in the half light this morning and then had a terrific sharp shower. No storms for us though but ESTOFEX have a level 1 for Ireland today:

Storm Forecast

Valid: Fri 23 Oct 2009 06:00 to Sat 24 Oct 2009 06:00 UTC

Issued: Thu 22 Oct 2009 20:00

Forecaster: TUSCHY

A level 2 was issued for the coastal areas of the E/SE Adriatic Sea and the Ionian Sea, SE-Italy and parts of Greece mainly for excessive rainfall and severe wind gusts.

A level 1 surrounds the level 2 mainly for severe wind gusts and locally heavy rainfall.

SYNOPSIS

A strong low pressure affects the central Mediterranean with unsettled conditions. This depression moves slowly southeastwards, crossing the Tyrrhenian Sea. Another strong depression draws near to Ireland during the night hours with wind gust approaching our severe criterion. Otherwise, quiet conditions convective-wise persist, either warm and stable over the Iberian Peninsula or cold over N/NE-Europe.

DISCUSSION

... Ireland 03 UTC onwards ...

A strong depression approaches Ireland during the night hours from the WSW. A strongly sheared warm sector covers Ireland and some MUCAPE is forecast. Even without electrified convection, severe wind gusts are possible within showers. Only the southern/western parts of Ireland were highlighted, bound to the position of the cold front.

Looks like it could be a late one:

And others are showing:

Seems today like a case of 'don't panic Captain Mainwaring'!

It is so unexpected - great treat! Mind you, COAST....regarding my dreams and you telling me to lay off the cheese, this looks exactly how I dreamt it!!

You obviously have a mystical power there Merlin Harry! Perhaps you should apply to the MetO and they could save £billions on supercomputers!

More cheese for Harry please....

[Guest North Sea Snow Convection]

I saw the lightning from those storms whilst I was watching television last night. Only heard one distant rumble of thunder though.

[Azores Hi]

Just a quick update from me, got to work today to find that our production facility has been struck (or close to) in the night. Phone system is screwed, every computer wired to the network has been fried. All electrics are down with lots of melty bits all over the place.

Not a good day!

This is the downside of storms

[Harry]

You obviously have a mystical power there Merlin Harry! Perhaps you should apply to the MetO and they could save £billions on supercomputers!

More cheese for Harry please....

Indeed - and that mouse so looks like me lol

[Azores Hi]

Just a quick update from me, got to work today to find that our production facility has been struck (or close to) in the night. Phone system is screwed, every computer wired to the network has been fried. All electrics are down with lots of melty bits all over the place.

Not a good day!

This is the downside of storms

[Coast]

Data backed up to an offsite server AH? Good luck getting production up and running again - you know where I am if you need any equipment!

I have a friend who's transport and warehousing business was totally destroyed by a lightning strike and subsequent fire 3 years ago. That is sometimes the sad fact behind our mad hobby

[Azores Hi]

Yeah it's all backed up on servers in Holland and we don't work on C drives.It's just the hardware really. I think we've lost 2 laptops and at least 10 desktops plus the local network. Plus all phones and lots of leccy panels of great mysteriousness. Luckily, no one was hurt as everyone was at home, just think what may have happened if people were there, using the computers and the phones!

*shudders*

[Nick F]

Given a slight risk for marginally severe gusty winds and perhaps a tornado across Ireland, N Wales, N England and S/W Scotland in a storm forecast for today. Possible squall line with embedded storms may develop later this morning along cold front moving rapidly east out of Ireland given strong forcing of moist air and highly sheared environment close to the front.

http://www.netweather.tv/index.cgi?action=convective;sess=522db5aed145a8f32ab859d7652c8d20

[Tony Gilbert]

Slight Risk of Tornado Development 09Z-18Z NW Eire through to SW Scotland

Deep depression west of Ireland shown to develop cold front/ occluded front through Saturday effecting heavy rain and post frontal convective showers in the lee of the front, primarily Ireland & Scotland. GFS and MMN look to be in complete contrast?

Specific attention in this instance is given once again to the post frontal sector directly behind the occlusion NW Eire through to SW Scotland. GFS suggests subsidence and CIN lags way behind the initial frontal boundary allowing the potential for a secondary wave of isolated strong convection as a very dry mid level intrusion moving north overruns a moist axis advecting from the south across Ireland under a moderately deep upper trough.

A broad region of lift is likely to occur across the front left exit region of the strong upper jet stream. This outward fanning is now looking quite acute and has particularly caught my attention within the last model run. ...So ATM we have the potential upper support required for strong sustained convective storm cells. Very little veer at surface though speed shear within the lowest level is phenomenal. Such condition can often be attributed to strong narrow short tracked tornadoes! Low level spin can often become very efficient indeed and not necessary attributed directly to mesocyclone genesis!

Further risk of near severe wind gust pos 50kts ATM calculated based on a mean average flow between 800 mb and 600mb.

It is nevertheless noted that the forecast risk level ATM is delivered as 'SLIGHT'

UPDATE

Whilst strong winds and heavy rain are likely right across the board. The forecast here is applied specifically to the main convective zone likely today, based on what I can see in the models. Further region of shallow line convection or squall line could occur to the southern most regions of the UK as a sharp drop in humidity values is noted 700mb overrunning a very moist axis. GFS currently attributes very little to no CAPE to this region. So this could be a learning curve for me. If true convection is realised within this sector, severe gust level could easily occur.

Model update continues to show some basic potential. Forced accent looks restricted at ground level and forecast looks devoid of convergence. Hense my overall opinion now is that tornado development can only be regarded as Marginal/ Slight. Relevant height falls look to only partially overlap the flank side to the occluded front. So realistically the best risk for tornadoes and 'true' strong convective gusts will be better attributed to cells developing behind the main occlusion IMO.

Certainly some strong winds likely, especially within the blue box as noted. Severe gust will be the primary risk today

Edited October 24, 2009 by Tony Gilbert

[Stuart]

i nice to see i am in the red box but i dont think i see any it overcast and damp

[glasgow-guy]

was pretty stormy on sat night here in south Lanarkshire much preferred to the mild weather we have been having recently

lets hope this continues

[The watcher]

Had some very hefty rain/showers earlier this evening at about 9pm, only seen the convective storm alert. Shall keep an eye out tonight for any activity....

[Coast]

Nick F has put a storm forecast out for NI and Scotland, ESTOFEX have it out into the Atlantic during the day:

Storm Forecast

Valid: Wed 28 Oct 2009 06:00 to Thu 29 Oct 2009 06:00 UTC

Issued: Tue 27 Oct 2009 19:23

Forecaster: TUSCHY

SYNOPSIS

Anticyclonic flow covers SW Europe. Active pattern offshore - over the NE Atlantic - causes periodically batches of enhanced WAA, carrying the ridge and keep it more or less stationary during the forecast. A sharp trough over Scotland during the morning hours decays thereafter as geopotential heights increase downstream of an approaching depression. Meanwhile, a deep trough digs southwards over N/E-Europe and causes the advection of cold air at all levels. A weak trough over the south-central Mediterranean moves to the south while gradually degenerating.

Meanwhile others are showing:

[Nick F]

Think the threat for isolated storms will diminish by PM today across the area highlighted by my forecast issued last night, the threat was mainly for the early hours.

Potentially looks interesting next week as we see more unsettled Atlantic weather with a returning polar maritime airstream giving heavy showers and maybe storms towards windward coasts.

[Nick F]

Netweather storm forecast: http://www.netweather.tv/index.cgi?action=convective;sess=8d6f200199faef55df5113c655705d4c

[sammie]

TORRO have issued a convective discussion.

"TORRO CONVECTIVE DISCUSSION 2009/035

A TORRO CONVECTIVE DISCUSSION has been issued at 13:30GMT on Saturday 31st October 2009

Valid from/until: 13:30- 18:00GMT on Saturday 31st October 2009 for the following regions of the United Kingdom & Eire:

Eire

N Ireland

Parts of Scotland

THREATS

Wind gusts to 50mph; hail to 10-15mm diameter; CG lightning; isolated funnels/brief tornadoes.

SYNOPSIS

Short-wave trough is moving NE across the area. Showers and thunderstorms have developed in a reasonably sheared environment. Shear is rather unidirectional though, so persistent rotation is not expected within cells. However, brief mesocyclones could develop and brisk a risk of marginally severe winds and hail, although with a low risk of a brief tornado.

TONIGHT AND TOMORROW: A rapidly developing depression will move north-east later tonight and tomorrow. There is a risk of severe convection along the cold front, and around the centre of the storm, as it undergoes rapid cyclongenesis - severe gusts and isolated tornadoes will be the main threats.

Forecaster: RPK.

Edited October 31, 2009 by sammie