Storm risk - Monday 9th May onwards

[NO LONGER POSTING]

12 minutes ago, Flash bang flash bang etc said:

Sorry I couldn't clear the quote again :-/

 

so I'm confused by the forecasts because none of the ones I've read specify the timing for these storms. I'm assuming it's not for a while because it's raining here at the moment and nowhere on the radar do I see storms nearby (or evidence of any developing)

Today's storm risk comes later this afternoon and more so over night from imports.

Looking at the,sat the cloud is starting to break and thin over the channel and more so towards north east France and Belgium where we may import a storm overnight.

No cloud breaks or thinning of the cloud no storms seems to be the case. This too applies to others. 

Fingers crossed but it is a low risk currently and estofax are not interested 

[Chris.R]

 Wall-to-wall sunshine here now. I wonder if the rain band has gone north of me and maybe I can join in the action later. 

[Mapantz]

Estofex have the South coast within a 15% probability of lightning. Whatever develops later, will be pretty scattered is suspect..

A bit of a complicated setup!

[Spikecollie]

20 minutes ago, Surrey said:

Today's storm risk comes later this afternoon and more so over night from imports.

Looking at the,sat the cloud is starting to break and thin over the channel and more so towards north east France and Belgium where we may import a storm overnight.

No cloud breaks or thinning of the cloud no storms seems to be the case. This too applies to others. 

Fingers crossed but it is a low risk currently and estofax are not interested 

I don't understand Estofex sometimes. Météo France and Météociel have got rid of any convective activity in their forecasts for here in Limousin, France, but Estofex have us in a Level 1 area??? What do I believe and do I hit the hills on my bike? They seem to suggest a marginal risk for the south of the UK...

[Flash bang flash bang etc]

Regardless of whether anything happens the build up is always fun :-D

[Mapantz]

1 hour ago, Ben Sainsbury said:

Quite incredible seeing dewpoints up to 15-16'c in places. If people don't mind me asking what effects do dewpoints have on thunderstorms?

Higher dewpoints mean more moisture in the atmosphere, more moisture = more energy. I do believe that's all fine & dandy IF there are forcing mechanisms in play..

[Summer Sun]

Day 1 Convective Outlook

VALID 06:00 UTC Tue 10 May 2016 - 05:59 UTC Wed 11 May 2016

ISSUED 10:27 UTC Tue 10 May 2016

ISSUED BY: Dan

UPDATE 10:27 UTC SLGT has been extended farther W (as mentioned in previous discussion below) to cater for risk of slow-moving heavy showers / isolated thunderstorms this afternoon/evening. Overall, risk is generally sub-SLGT criteria (i.e. only 15-20% chance at most), but we keep SLGT for now purely to highlight areas most favourable for deeper convection later today. Profiles are saturated and lapse rates rather unimpressive, and so for now the risk of lightning is considered quite low, despite the potential for some heavy downpours to develop. There also remains scope for imported remnant convection from the nearby Continent through tonight across some S / SE areas.

Large upper low continues to sit west of Iberia, with a surface low forming close to a waving frontal boundary across southern Britain on Tuesday. Overall, the risk of lightning in any one location is considered quite low, but two SLGT areas have been issued to highlight zones of slightly better potential, albeit still quite low-end.

A combination of insolation and low-level wind convergence may allow a couple of heavy showers / thunderstorms to form over SW Ireland, before more general showery precipitation arrives from the east later in the day. 

Meanwhile, to the south of a zone of showery precipitation (with embedded convective elements) across Wales - Midlands - East Anglia, some insolation may develop across southern counties of England, and coupled with a very moist low-level air mass and wind convergence, there is potential for scattered heavy showers and a couple thunderstorms here also. However, biggest uncertainties are the extent of cloud cover and whether sufficient insolation can develop to generate deep convection. Furthermore, depending on exact developments with wrap-around process, if cloud breaks do extend farther west towards the SW Peninsula (which is possible), then the SLGT would in theory need to be extended to here also - but current conflicting guidance reduces confidence here somewhat.

Given low cloud bases and low-level convergence, there is potential for a few funnel/weak tornado reports.

http://www.convectiveweather.co.uk/forecast.php?date=2016-05-10

[NO LONGER POSTING]

 

Could be better, could be a lot worse.. Let the game begin.. or not

[steve86]

Warm and very muggy here in Gosport. The suns trying hard to come out. A lot of moisture around after the rain this morning. 

[Mapantz]

The sun is trying to break through here now.. Temp: 18.4°C - Dew: 15.4°C

I'm off to do some more paving, so it will probably rain.   

[steve86]

Certainly some nice juicy showers on the Cherbourg peninsula. For me tho I think I need to be looking more east?

[stainesbloke]

Belting it down here, proper soaking rain and drizzle all morning. Still feeling quite warm and muggy 

[TropicThunder]

After a damp and murky morning, the sun is now out here and it's feeling very warm and muggy. 

Looks like some sharper showers are already starting to form on the back edge of the rain band.

[Nick F]

Provided cloud breaks, surface heating and onshore/wind convergence may trigger some storms this afternoon - early evening across southern counties of England, far south Wales and also Ireland. Already breaks across the SW, English Channel, and Ireland.

Here's my forecast for today:

Storm & Convective Forecast

Issued 2016-05-10 10:28:51

Valid: 10/05/16 0600z to 11/05/2016 0600z

DAY 1 CONVECTIVE / STORM OUTLOOK

Synopsis

An upper low is slow-moving over SW Europe during Tuesday, centred off west coast of Portugal. An area of surface low pressure deepens slight over the Bay of Biscay, while a shallow low forms over SW Britain later along slow-moving, waving frontal zone stretching from E Anglia to SW Wales by 00z Wednesday.

DAY 1 CONVECTIVE OUTLOOK FOR TUESDAY 10TH MAY

... S ENGLAND and S WALES ...

Frontal boundary slowly lifting north across southern areas this morning is bringing thick cloud and mostly dynamic-induced rainfall ... so the airmass is generally stable this morning across England and Wales. However, there looks potential for some cloud breaks developing over the far south of Wales, SW England and southern counties further east into the afternoon which may allow sufficient surface heating to destabilise the atmosphere over these areas. Fairly steep mid-level lapse rates, dew points reaching the mid-teen and surface heating could create several 100 j/kg CAPE in the areas we see brightness or sunshine develop. Surface breeze convergence and upslope flow of onshore winds, particularly inland across Devon and Cornwall and along higher ground inland from south coast further east, may be the trigger for afternoon localised slow-moving thunderstorms which may produce hail, gusty winds and up to 20mm/per hour leading to risk of localised flooding. Given low LCLs / cloud bases, a few funnels, even brief weak tornadoes /waterspouts can't be ruled out with stronger convective/storm updrafts along convergence zones.Weak vertical shear and isolated risk of storms means will refrain from highlighting potential for organised severe weather.

Further heavy showers or thunderstorms developing over northern France may drift north this evening across southern areas of England, though storm coverage is far from certain - so best seen as an isolated risk for now. 

... IRELAND ... 

GFS develops a few 100 j/kg CAPE this afternoon/early evening across northern and western parts of Ireland, though this dependent on cloud breaks. So potential for one or two storms here today PM, with risk of hail ,gusty winds and localised flooding

Edited May 10, 2016 by Nick F

[Mapantz]

There is some weird clouds going on to my SE - condensation lifting underneath the cloudbase. It's perfectly still and very humid..

Edited May 10, 2016 by Mapantz

[knocker]

I see Nick mentioned N. Ireland

[Snowkissed]

I thought I was beginning to see some rotation in those clouds Mapantz! However, just scuds developed

[Mapantz]

Told you - mix up a load of sand and cement, and the heavens opened!

[Harry]

Not holding a great amount of hope for London and the SE at the moment. While it's still warm and muggy the cloud hasn't thinned in the slightest. Keeping my expectations at slightly above zero for the foreseeable future.

[Mapantz]

Just a couple of quick shots..

[Raidan]

What a horrible day been raining all day sometimes light and some moderate from the time i got up and still raining since finishing work got soaked walking home, haven't seen the sun all day and doesn't feel humid like yesterday, only just sat down and haven't had a look at anything yet but hoping something of interest might be on tonight or atleast a risk of something thundery.

[MP-R]

Watching those intensifying showers down south is like watching slugs move across a wet patio - everything is happening so slowly today!

[knocker]

Now with some surface heating.....................

[alexisj9]

1 hour ago, Harry said:

Not holding a great amount of hope for London and the SE at the moment. While it's still warm and muggy the cloud hasn't thinned in the slightest. Keeping my expectations at slightly above zero for the foreseeable future.

It's been sunny here for a while, although there is also some cloud about. Feeling fairly humid to boot. Even before the sun burnt through properly, there were lot's of sun dogs showing through the upper cloud.

[Harry]

20 minutes ago, alexisj9 said:

It's been sunny here for a while, although there is also some cloud about. Feeling fairly humid to boot. Even before the sun burnt through properly, there were lot's of sun dogs showing through the upper cloud.

You're lucky - skies have remained leaden over London and continue to do so - mist, murk, yuck!!

Realistically we need to hope that any storms that develop your way will then drift NW/W.