Convective/storm Discussion Thurs 23>>>>>>>>>

[Harry]

Wednesday and into Wednesday night, has to be good bet for quite a few areas!

Weather front attached to a fairly large area of low pressure, expected to stall over western areas, allowing pulses of heavy rain to run up through the day behind a warm front! Air will be streaming out of the Bay of Biscay/Spain for a large part of the day. CAPE/LI looking reasonable for many areas too, with the storm risk at 50% or higher for quite a large portion of the UK, more so towards the East into evening time - up to 60-70% for a few areas, when an cold front preceded by an occluded front/trough sweeps in during the overnight period.

I cant forsee at the moment this being an import/MCS style scenario, as France seems predominately influenced by H pressure - plus little/no CAPE there at this stage. However, to me it looks fairly promising for some storm activity at least.

Thoughts?

[Harry]

I am going to go on a hopefully self educating punt here...

I have had a bit of fun on paint to help explain my thought processes, i.e. in the post above.

I can't help but think there is some potential for storms, while MetO/BBC are not really having it! As per usual, there is no thunder mention for Wednesday at this stage, just 'heavy downpours', downpours which are expected to last right the way through the night particularly across the SE and EA!

The two MetO pressure chart overlays, and also the jet chart for 1800 on Wednesday, hopefully explains why I am perhaps stupidly hopeful :lol:

Thoughts?

[NL]

I am going to go on a hopefully self educating punt here...

I have had a bit of fun on paint to help explain my thought processes, i.e. in the post above.

I can't help but think there is some potential for storms, while MetO/BBC are not really having it! As per usual, there is no thunder mention for Wednesday at this stage, just 'heavy downpours', downpours which are expected to last right the way through the night particularly across the SE and EA!

The two MetO pressure chart overlays, and also the jet chart for 1800 on Wednesday, hopefully explains why I am perhaps stupidly hopeful :lol:

Thoughts?

I have the feeling that the HP affecting much of Europe may scupper the chance of storm development to the SE as i think its influence will be felt down the far eastern side of England

particularly in that location as current charts stand, could even influence my part of the country all depends the positioning of the said anti-cyclone. But we live in hope. Its been quite unusual up here with just about the annual thunderdays reached already, although most of the storms were of low intensity the cloud structures were visually outstanding..

Hoping for some more of this from last Friday gone.

[Coast]

UKASF bravely out on their own this morning with the following:

Storm Forecast Issued: 2009-07-27 20:37:00

Valid: 2009-07-28 00:00:00 - 2009-07-28 23:59:00

Regions Affected

Northern Ireland, most of Scotland ( remaining areas of Scotland, Northern England, Midlands, Wales and Southwest England are included in the WATCH )

Synopsis

Several centres of LOW pressure to the west of the United Kingdom, and an area of HIGH pressure over the Low Countries, will dominate the weather across the UK on Tuesday. North of an approaching warm front, scattered showers and thunderstorms are expected to develop as a result of troughs, convergence zones and occlusions embedded in the southwesterly flow over Scotland and Northern Ireland. Northwest Highlands of Scotland exhibit the best potential for thunderstorms, and given the Polar Maritime airmass, hail can be expected in many of the showers. Showers will decrease in coverage across Northern Ireland late morning due to outbreaks of persistent rain approaching for the afternoon. Showers will decrease in coverage across Scotland as the outbreaks of rain over Northern Ireland work northwards during the early evening.

TBH I think it's a 'miss' but those in NI and Scotland might want to keep an eye on things just in case:

[azores92]

well the models cant make their mind up this morning on tomorrows development, it looks like western wales could get a lot of rain, say up to 2 inches is possible, but also parts of dorset or the south coast could potentially see this band of very heavy rain tracking NEwards, also giving a few places say across central southern england a good dosage. its certainly going to deliver some large accumulations for certain areas. i think though, even 36 hours out, it is still hard to say where the main areas affected will be. last nights graphics showed it moving up through the midlands, for instance, and as it stands this morning, it looks like most of western wales and the south west will be hardest hit.

[Coast]

I can't help but think there is some potential for storms, while MetO/BBC are not really having it! Thoughts?

Out of all of this week I think Wednesday gives the most potential so far for the week. But I think it will be a long drawn out day with maybe something in the West first thing as your analysis indicates and something less likely in the middle/East early evening.

[Lynxus]

Just heard on the weather that there could be storms about today.

Since when lol?

[Harry]

Friday into Saturday has to be worth keeping an eye on too, with quite a similar scenario, if maybe slightly more favourable than the coming couple of days.

High pressure expected to move in through Thursday into Friday - aligning yet another Low pressure system to the West, High to the East drawing up moist southerly wind flows.

While there doesn't seem to be many indications screaming storm activity, either for tomorrow or the first part of the weekend, possibilities do look to be there IMO.

Edited July 28, 2009 by Harry

[Guest North Sea Snow Convection]

Coastal supercells look unlikely imo

Edited July 28, 2009 by North Sea Snow Convection

[Coast]

Coastal supercells look unlikely imo

If they hit, they'll be in your back garden Tamara!!!!

[Paul Sherman]

Coastal supercells look unlikely imo

Lol Yeah...............But

If the main bulk of the rain and Embedded Thundery Activity continues to affect the SW And onto Wales and the North West and Western Parts of the Midlands, If and its a Big If we can get a few Surface Based Storms to fire in the Area to the SE Of this area then we could have some potentially Severe Storms in the Offing mainly for the SE Mids, SE England and East Anglia from the 4-8pm Timeframe. One to watch and some of the Forecasting sites 'might' pick up on this for tomorrows outlook.

Paul S

[Harry]

Lol Yeah...............But

If the main bulk of the rain and Embedded Thundery Activity continues to affect the SW And onto Wales and the North West and Western Parts of the Midlands, If and its a Big If we can get a few Surface Based Storms to fire in the Area to the SE Of this area then we could have some potentially Severe Storms in the Offing mainly for the SE Mids, SE England and East Anglia from the 4-8pm Timeframe. One to watch and some of the Forecasting sites 'might' pick up on this for tomorrows outlook.

Paul S

A very small part of me doesn't want storms in this set up - I dont think I could stand the "SE gets it all again" rubbish! The vast majority of me says YES PLEASE!

A big part, as often with our fair island, will hinge on timing! Somewhat similar scenario in June had some low risk indications of storms , some suggesting the front would move through bringing rain and v little, or no convective activity. What we got was a lastminute.com MCS rattle out of France because the weather front stalled....more of the same would be nice

[Paul Sherman]

Well the Midlanders should be happy as I would only rate it as 10-20% atm

It is all dependant on if the Main rain band stays in a certain place and wether anything can fire further to the SE Later in the Afternoon, A big 'IF' At the moment Harry!

Paul S

[Nick F]

GFS is not keen at all on any instability away from the waving cold front that moves in from the west tomorrow, lapse rates look rather weak away from the frontal boundary and post frontal airmass. So, would expect best chance of storms to be embedded along cold front and also in the post frontal airmass over Ireland tomorrow. Cold front clears the east around and after midnight tomorrow.

[Harry]

Well the Midlanders should be happy as I would only rate it as 10-20% atm

It is all dependant on if the Main rain band stays in a certain place and wether anything can fire further to the SE Later in the Afternoon, A big 'IF' At the moment Harry!

Paul S

More often than not an 'if' for our green and pleasant land

[Coast]

Severe Storms in the Offing mainly for the SE Mids, SE England and East Anglia from the 4-8pm Timeframe. One to watch and some of the Forecasting sites 'might' pick up on this for tomorrows outlook.

+ possibly into the early hours if it's coming Paul?

[Paul Sherman]

GFS is not keen at all on any instability away from the waving cold front that moves in from the west tomorrow, lapse rates look rather weak away from the frontal boundary and post frontal airmass. So, would expect best chance of storms to be embedded along cold front and also in the post frontal airmass over Ireland tomorrow. Cold front clears the east around and after midnight tomorrow.

But UKMET Is a lot keener Nick, so 1 For and 1 against atm

[MP-R]

Some beefy showers appearing ahead of the front over West Somerset, Devon and the Bristol Channel.

[Harry]

Hi Neil, was that taken sometime around 6pm? If so that passed directly over Cranbrook around 5pm.

Sorry it's late, I've been working since 1pm and only just got in - but boy what a day!

Firstly, frequent torrential downpours this morning, along a discrete line, gave us 12.9mm by 11:38, making it the 2nd wettest day of the year before midday!

No thunder during the morning, but some of the most torrential downpours I have ever seen!

I went to work around 1pm, it chucked it down briefly whilst driving the 10 miles to Cranbrook (south of Maidstone) but for most of the afternoon it stayed dry and relatively sunny from what I could see out of the window at work (Cranbrook).

I left at 4:50pm for my dinner break. Upon leaving the entrance to the supermarket I work in, immediately the clouds grabbed my attention. To my east there was a lot of low, black scud rapidly moving in different directions. Overhead the cloud was the plain 'milky white' but to my northwest the clouds were smooth and purple, typical of a storm. I could see hail curtains coming down to my northeast and distant constant rumbling.

I have been informed by a few people that a storm moved over my house around 4:30pm, which I did not see in Cranbrook (that's how localised these things are). The storm over my house:

Once I had indentified the storms were all to my north, I decided to have a mini storm chase during my lunch break and quickly hopped in the car and drove into Maidstone (13 miles). As i drove there i noticed huge towering anvils ahead of me, somewhere over the Thames Estuary i presume, whilst the storm i was initially chasing actually moved eastwards whilst i drove north, and it wasn't long before i was under clear blue skies. By 5:20pm i gave up, and turned round to drive back to work.

However... once i had turned the car round, I noticed huge CB's to my south - right where I had just come from! Bearing in mind i had no access to radar at the time, I didn't realise there were cells approaching my work from the west! I drove back as quickly as I could, arriving back at work around 5:45pm.

It took a while for things to finally get going, and by the looks of it we only scraped the northern edge of the storm, the majority of it went over Hawkhurst (4 miles south of Cranbrook).

However, I sat in my car for a good 30 minutes, with the window wound down and watched the various forks and sheet lightning accompanied by very loud thunder, loud and boomy enough to shake the car!

It was great

18.1mm is the total today

Just remembered I took these pics...here are a few snaps of the storm which ran into C/S Kent on Friday evening...one of the best Cb's I've witnessed

[Nick F]

But UKMET Is a lot keener Nick, so 1 For and 1 against atm

Do you have insider info or something? Lol.

12z UKMO meso does break out some convective-type precip. across SE England ahead of the main frontal rain band tomorrow afternoon - but it's a brief window before the cloud moves in with front as it advances east.

[Costa Del Fal]

Looking at the GFS we could see alot of heavy rain tomorrow afternoon and evening. Local flooding perhaps. A few of ingredients that are ideal for storms look to be there tomorrow particularly the LL Shear. Is anything expected tomorrow here?

[Paul Sherman]

Do you have insider info or something? Lol.

12z UKMO meso does break out some convective-type precip. across SE England ahead of the main frontal rain band tomorrow afternoon - but it's a brief window before the cloud moves in with front as it advances east.

:ph34r: :lol:

[Lynxus]

INCOMINGGGG

Right, with that over with..

Is this stuff just rain? or is it going to give us any thunder?

Am i right inthinking this stuff just hitting land will pass over tonight and then more will come along or is this the whole shebang and will just dump plenty of the wet stuff on us?

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

Is it possible that tomorrows event will be similar to a few weeks ago, when the north east got especially soaked and the east got tonnes of lightning?

[Wilxy]

Raining here now not heavy but big drops of rain.