Convective / Storm Risk Discussion - 23rd July 2013 onwards

[East_England_Stormchaser91]

Somre more lightning shots from Monday nights storm.

lightning 1.PNG lightning 2.PNG

lightning 3.PNG lightning 5.PNG

Simply awesome Dave. That really was a hell of a storm. Cannot believe how long it went on for either! Reminded me of the 90's big time!

[Harry]

NMM going for a direct Southern England/South East England hit on Saturday night...

 

To give an idea of the detail needing to be pinned down, the GFS shows the system has cleared southernmost parts by 21z, straddling the Midlands and EA. NMM at midnight has largely in the Channel at 00z.

Then we have E/W shift. On top of that, there looks to be the potential for monster MCS/supercells over France in the coming days including Today, tomorrow and Saturday, which could dramatically alter proceedings for us.

Exciting yes, but we'll probably not know a great deal more until Saturday morning/lunchtime

[Robbie Garrett]

It's going to be a radar watch event come Saturday night that's for sure. I think this could be our year. God I've waited 14-17 years for an overnight MCS. I was scared back then, now I want to enjoy there shear power...

[tcc]

You just know it'll end up going along the Channel even though when it leaves the French coast it was showing as heading directly North, then it'll veer NE maybe clipping the SE! I'm certainly expecting something like that to happen! I guess the years of disappointments have got to me!

[Harry]

It's going to be a radar watch event come Saturday night that's for sure. I think this could be our year. God I've waited 14-17 years for an overnight MCS. I was scared back then, now I want to enjoy there shear power...

Same here...it's been a long time, although while Monday night wasn't an MCS it felt like it on the coast. For a spell of 20-25 minutes lightning was flashing every 2-3 seconds across different parts of the sky during a spell of about 2-3 minutes every second (on a few short occasions pretty much constantly). When I woke up I'd have sworn blind it was an MCS until I looked at the radar.Now I've got the knack of this photography lark I would like another go :-D

[Coast]

You just know it'll end up going along the Channel even though when it leaves the French coast it was showing as heading directly North, then it'll veer NE maybe clipping the SE! I'm certainly expecting something like that to happen! I guess the years of disappointments have got to me!

 

Damn we are all becoming so pessimistic (or is that realistic?)  

[Nick F]

Storm forecast from me for today:

 

Valid: 25/07/2013 1000z to 26/07/2013 0600z
Headline: ,,, THERE IS A RISK OF THUNDERSTORMS ACROSS NERN UK & IRELAND ...

Synopsis
An upper low and surface low pressure system is centred to the west of the British Isles during the forecast period, a cold front will move E and NE across the UK during the day, while a shortwave trough moves in across Ireland this afternoon.

... N ENGLAND, N MIDLANDS, E ANGLIA, SCOTLAND AND EIRE ...

A rather humid airmass covers the UK and Ireland today, with dew points of 15-18C typically on current obs. Surface heating will allow the atmosphere to become increasingly unstable with several 100 j/kg of CAPE by the afternoon, more particularly across northern and western areas - where air aloft will be colder/ steeper lapse rates. Scattered heavy showers and storms will likely develop in the above areas as a result, perhaps becoming focused near cold front moving N and NE across mainland UK and along post-frontal trough moving in across Ireland. Some sea breeze convergence towards NE England/E Scotland in generally slack flow in the north may further aid storm development here. Although vertical directional shear will be generally weak across northern Britain, jet stream max moving NE will create addtitional lift and allow sufficient updraft/downdraft seperation for some storm organisation, particularly near cold front. Associated dry air intrusion spreading NE with jet will also enhance storm development and increase risk of strong winds lowering to the surface along with increasing risk of hail. So any storms maybe accompanied by localised strong wind gusts, hail (perhaps isolated up to 1-2cm) and torrential rainfall leading to flash flooding

 

[Nick F]

You just know it'll end up going along the Channel even though when it leaves the French coast it was showing as heading directly North, then it'll veer NE maybe clipping the SE! I'm certainly expecting something like that to happen! I guess the years of disappointments have got to me!

 

Well, certainly a risk that we'll just end up with heavy rain while the storms stay over the over side of the Channel. The dreaded eastward shift has to be factored in, as the models have the habit of initially breaking down plumes too far west. Certainly not holding my breath for London, though Kent may be quids-in.

Edited July 25, 2013 by Nick F

[Coast]

Cautious words from MetO latest:

 

 

Yellow warning of Rain

 

Issued at: 

1051 on Thu 25 Jul 2013

 

Valid from: 

1500 on Sat 27 Jul 2013

 

Valid to: 

0600 on Sun 28 Jul 2013

 

Heavy showers or thunderstorms may affect at least some southeastern and eastern parts of England later on Saturday or during early Sunday. The public should be aware of the risk of localised disruption to travel due to surface water flooding.

An area of heavy showers and thunderstorms developing over France during Saturday may move northwards to affect at least parts of eastern and southeastern England later on Saturday or early on Sunday. There remains marked uncertainty concerning the extent of these heavy showers and thunderstorms, with there being a chance that they could also spread into parts of southern and central England. However, at this stage southeastern England is thought to be at the greatest risk of being affected.

 

 

http://www.metoffice...Time=1374966000

Edited July 25, 2013 by Coast

[Nick F]

Cautious words from MetO latest:

 

 

 

http://www.metoffice...Time=1374966000

 Yep. *may* being the operative word!

[Coast]

The media are already spinning interpreting it:

 

 

Weather warning: heavy rain and thunderstorms for the weekend, says Met Office

 

Sun-lovers looking forward to another blazing weekend may have to rethink their plans after the Met Office issued a weather warning of possible heavy downpours and thunderstorms for parts of Britain. 

 

The Met Office have issued a weather warning of possible heavy downpours and thunderstorms for parts of Britain at the weekend 

With many schools about to break up for the summer and thousands planning to set off on holiday, the forecaster cautioned that some regions faced a risk of flooding and travel disruption from Saturday evening into Sunday. The Met Office’s “yellow†warning of rain was prompted by concerns that heavy showers and thunderstorms expected over France on Saturday could move north to affect south-east England and East Anglia.

 

It added: “The public should be aware of the risk of localised disruption to travel due to surface water flooding.â€

However, the weekend will not be a complete washout. England and Wales are expected to enjoy dry and warm conditions first thing on Saturday before the unsettled weather spreads in from the south, and many areas will see sunny spells on Sunday

 

 

http://www.telegraph.co.uk/topics/weather/10201584/Weather-warning-heavy-rain-and-thunderstorms-for-the-weekend-says-Met-Office.html

[Cloud 10]

Latest radar looking interesting for Ireland with that slow moving trough getting

its act together,with a couple of strikes already showing up.

 

 

 

 

[Neilsouth]

Latest Forecast

" We are keeping an eye on the bay of biscay into france for the southern half of the uk sat night-sunday "

" Intense rainfall with big storms possible "

" Will keep you updated nearer the time "

[Marcus_surfer]

Sunday looks interesting too for western areas, low pressure moves in bringing heavy showers and thunderstorms.

[nitro_deluxe]

Interesting few days...

Back to here and now - a few well scattered showers now breaking out, quite sharp echoes Cleobury way, heading towards Bridgnorth, cauliflower clouds certainly blossoming in the right direction.. Expecting the first sferics to appear in the next few hours, very hit and miss affairs, although chances increase throughout the afternoon for a hit

Temps around 23C, quite humid feel but not uncomfortably so.

[pad199207]

Things are lightening up North of me now ugh so moving away

[Stuart]

had some thunder not that long ago But did not see any Lighting

[Rammie]

Daughter lives in East county Cork. Said was brilliant ts last night. Pics on the way.

[PMPhotography]

Interesting read.

The first recorded sprite over the UK from the storms that clipped us on the 24th.

http://www.rmets.org/britains-first-sprite-recording

[Nick F]

A rash of sferics over N Ireland and the NE of Ireland currently, 12z Valentia radiosonde ascent in SW Ireland showing quite an unstable troposphere to surface heating with steep lapse rates, cloud tops to around 30,000ft possible if the temp is lifted one or two degrees from the 20C shown on the skew-t.

 

 

06z GFS still keen on spreading heavy rain north Saturday PM, as the plume over France destabilises on the NW periphery, though best instability/CAPE stays on near continent, with some instability fringing into the SE corner.

[Cloud 10]

Northern Ireland looks to be the storm hotspot at the moment.

 

 

 

A couple of cells firing around the Liverpool area now as well.

[NUT]

Rain should be falling over me right now but nothing's actually falling.............YET! You just can't escape that feeling though that the atmosphere is ready to go boom at any second. It has that feeling about it

[Stuart]

SKYWARN UK SEVERE THUNDERSTORM WATCH #024
ISSUED: 1200UTC THURSDAY 25TH JULY 2013

SKYWARN UK FORECASTS THE POTENTIAL FOR SEVERE THUNDERSTORM CONDITIONS AS FOLLOWS:
HEAVY RAIN LEADING TO A RISK OF LOCALISED FLOODING - NORTHERN IRELAND, NORTHERN ENGLAND, SOUTHERN AND WESTERN SCOTLAND

IN EFFECT FROM 1200UTC UNTIL 2300UTC THURSDAY 25TH JULY 2013

POST-FRONTAL SHORTWAVING IN AN UNSTABLE MOIST ENVIRONMENT, FOCUSSING SLOW MOVING THUNDERSTORMS GENERATING INTENSE RAINFALL

DISCUSSION:
THERE IS GOOD MODEL AND PARTNER AGENCY CONFIDENCE IN THE POSSIBILITY OF A SEVERE THUNDERSTORM RISK THROUGH TODAY AND OVERNIGHT. RECENT RADAR AND SATELLITE IMAGERY CONFIRM THE INITIATION OF A LINE OF CONVECTION WHICH, GIVEN LITTLE DEEP LAYER SHEAR, WILL PROGRESS SLOWLY THROUGH NORTHERN IRELAND. WIDESPREAD INSTABILITY WILL LEAD TO FURTHER INITIATION OF STRONG CONVECTION ACROSS THE WATCH AREAS. GIVEN THE DEEP MOISTURE AVAILABLE, RAINFALL RATES WITH THESE CELLS WILL BE INTENSE AND FLASH FLOODING IS A POSSIBILITY. THOUGH THERE IS LITTLE SHEAR FOR ORGANISATION, ESPECIALLY IN THE NORTH, THERE IS STILL SUFFICIENT FORCING FOR SUSTAINED MATURE STORMS WITHIN THE SHOWERY REGIME. THIS WATCH MAY BE UPDATED OR UPGRADED. PLEASE MONITOR WEATHER AND TRAVEL INFO AS NECESSARY.

SPOTTER ACTIVATION IS REQUESTED AND SPOTTERS ARE REQUESTED TO REPORT ALL FACTORS EXCEEDING ACTIVATION CRITERIA.

 

http://www.skywarn.org.uk/current.html

[Chris.R]

Just had a torrential shower here, no thunder though.

[Coast]

 

TORRO CONVECTIVE DISCUSSION 2013/006 

 

A CONVECTIVE DISCUSSION has been issued at 13:05GMT on Thursday 25th July 2013 

 

Valid from/until: 13:05 - 19:00GMT on Thursday 25th July 2013, for the following regions of the United Kingdom & Eire: 

 

Parts of (see map) 

 

 

Eire N Ireland 

 

THREATS 

 

Isolated tornadoes; hail to 15mm diameter; wind gusts to 50mph; CG lightning 

 

SYNOPSIS 

 

A low-level convergence zone, an unstable atmosphere, and reasonable low-level moisture has allowed thunderstorms to develop. With marked low-level convergence across the area, isolated tornadoes are possible. The wind fields across N England and Scotland are less conducive at the moment although the area will be monitored - tornadoes are not out of the question here. 

 

Forecaster: RPK