Storm/Convective Discussion

[dogs32]

Huge MC'S KICKING OFF in the Bay of Biscay...

Its hard to tell if they are moving north or East...

Interesting day with the suns heating...Should be some fun

[dogs32]

which way is that large Storm in the Bay moving

[*AL*]

which way is that large Storm in the Bay moving

Towards us i hope Dogs!!

[Roger J Smith]

This could be quite a day for UK storms, as a slow-moving frontal boundary oriented from central NI through Dublin and southwest Wales, Cornwall and the French Atlantic coast drifts east at a very slight speed, while cells entrain along the boundary and run in a generally due northerly direction. The net (weather) motion will be east at about 10-15 knots. By mid-day and early afternoon, there could be some very heavy storms in Devon, Somerset and Dorset, also parts of Wales and possibly the Severn valley. Later in the afternoon the complex may speed up slightly and approach a line from about Cheshire to West Midlands to Wiltshire and Hampshire. There may also be a separate MCS forming late afternoon into the evening for the southeast.

But in the main band of storms, the very slow forward motion of the line will lead to locally torrential rainfalls of 75-100 mms locally (that's 3-4 inches) and some severe flooding could result especially over Somerset and Devon.

Northern Ireland should have quite a good storm day, and eastern Ireland will see more development behind this first wave later on.

Tomorrow also looks quite promising for severe storms, first of all the slow-moving front should redevelop over eastern England, then a second area should move into Ireland during the day and reach western parts of the UK by late afternoon.

While heavy rain looks like the main severe threat, some hail and gusty winds may develop, but another feature will be the intense thunder and lightning as days of hot, dry weather have charged up the ground.

[maidstone weather]

it hasn't moved east as GFS promised, it's moved north west through irish sea to ireland,

not sure what is going but all the forecasters are in bed and so should I as well now

cheers

to be fair, the GFS didn't expect it to move any further inland until around 9am in the morning. It always had it over the extreme southwest for much of the night

[SteveB]

I did'nt think the sun would be out this morning, but fairly cloudless skies.

[londonsnow]

encouraging signs this morning. yesterday i was becoming resigned to a frustrating limp from heatwave to fresher condions in areas away from the west and especially the southeast. it so often happens. today i'm more confident of some sort of light show to usher in the cooler air. certainly eire looks like it was battered last night, and what a monster in biscay at the moment.

[Doc]

Cracking little storm here between about 3.45am (that's when I was woken!) and 4am. Lots of extremely close strikes and shattering thunder. Dropped over 30mm of rain. First decent night storm I can remember for years here.

[ballybabe12]

Raining steadily in Belfast now. No sign of any thunder. Not going to hold my breath either.

[fromey]

what happened last night, i was expecting to be woken in the middle of the night!!!

woken up this morning bright blue sky and temps of 19.8c.

is this front going to pass over us or is it just going to sit there,looking at the radar before i went to bed i though it would be teeming it down.

not another let down i hope??

[Nick F]

The front will get a kick up the butt and start moving further east and northeast during the day ... though many eastern, central and northern areas of England staying dry until after dark

[Costa Del Fal]

Lovely Hot morning here though juding by forecasts such as the Met Office then no storms can be expected.

[SteveB]

surprised to see the sun ot this morning, as Nick.F say's, this should help to give the front a bit more energy.

[dogs32]

I reckon later with all the temps this Front will ignite for tonight..

well thats the assumption

Edited July 2, 2009 by dogs32

[SteveB]

I reckon later with all the temps this Front will ignite for tonight..

well thats the assumption

Lets hope so, if it does it could be a good display

[dogs32]

like most people Steve I was quite surprised to see blue skies this morning...

Though Im looking at this as a positive for more energy for the thundery showers as they push up towards us later....

keeping a close eye on Sat24 infra red.....

watching the deep white lumps breaking off from the main MC...

As they try to spread north..

Hopefully there will be some growth down towards the channel in the next few hrs..

[Coast]

Well a quick round up of the usual suspects gives us:

ESTOFEX

Storm Forecast

Valid: Thu 02 Jul 2009 06:00 to Fri 03 Jul 2009 06:00 UTC

Issued: Wed 01 Jul 2009 19:31

Forecaster: PUCIK

A level 1 was issued for Great Britain and Ireland mainly for excessive precipitation

SYNOPSIS

Rather inconspicuous synoptic setup has established over Europe and no major changes are anticipated during this forecast period. A ridge of slightly higher geopotential heights at midlevels will stretch from SW Mediterranean into Scandinavia. To the east, a shallow trough will reside over Russia, Ukraine and Balkan states. The only apparent change to the setup is an approaching short-wave trough, which is predicted to affect the weather across Great Britain, Western France and Spain. Frontal system, associated with it, will cross the area in the late evening and night hours.

Widespread diurnally driven thunderstorms are expected over most of Central, Western and Southeastern Europe. In weak wind shear, thunderstorms will stay mostly poorly organised. Due to the slow motion of individual cells, high moisture content , local heavy rainfall event is quite possible, especially over the mountainous areas.

DISCUSSION

...Great Britain...

Ahead of the approaching cold front, soundings suggest that an unstable air mass has developed over the islands.

air-mass or air mass, not airmass, as far as I know Thunderstorms have already commenced (as of 18Z Wednesday) and for this forecast period, two rounds of convection are possible. GFS suggests that an MCS will affect southern parts of England, Wales and Ireland by early morning and noon hours, developing in vicinity to the cold front and moving northwards. Another round is possible in the afternoon and evening hours, mainly over Scotland and England, where models hint on enhanced CAPE values. Due to the high moisture content of the troposphere, slow motion and predicted formation of convective system, it seems possible that significant precipitation amounts could accumulate locally.

UKASF

Storm Forecast Issued: 2009-07-01 20:59:00

Valid: 2009-07-02 00:00:00 - 2009-07-02 23:59:00

Regions Affected

Southwest England, Wales, Northwest England, West Midlands, Central Southern England, North & West Scotland ( all of Scotland, Northern Ireland, Wales and much of England, excluding the extreme east, are included in the WATCH )

Synopsis

The forecast for Thursday is very complicated to determine due to different ideas put forward by various models. What seems certain is a gradual breakdown from the very hot conditions as a cold front makes further progress eastwards during the forecast period. An MCS over NW France is expected to move NNW-wards through the rest of tonight, arriving in Devon/Cornwall during the late early hours. Torrential rain, perhaps with hail, and thunder and lightning can be expected here during the remaining hours of tonight. Furthermore, the models are keen to break out thunderstorms either ahead of and/or along the leading edge of the cold front as it moves across parts of the West Country/South Wales during the late morning and early afternoon, with an increased risk of thunderstorms across the Midlands when the cold front arrives during the evening. Scattered thunderstorms are also expected across northern and western Scotland, primarily in response to daytime heating and uplift from the mountains. These will decay slowly during the evening. Thundery, blustery showers are expected over western Ireland and parts of Northern Ireland once the cold front clears through, though the risk of storm development keeps fluctuating on consecutive models, and as a result we have only issued a WATCH for the mentioned areas for the time being. Meanwhile, a convergence zone is expected to develop down the spine of Britain during the evening hours, preventing the eastwards progression of the cold front temporarily. As a result it is expected that any associated rain and storms across central southern England will decay during the evening, whilst storms are likely to move and intensify into/across the north Midlands and up to Northwest England, lasting for much of the evening hours. There is also good consistency between the models for a line of elevated thunderstorms to move over the Channel and intensify late in the forecast period, heading in the direction of the Southeast but not actually arriving there until the early hours of Friday. Due to the various uncertainties, an update may be issued during Thursday.

TORRO

A TORRO CONVECTIVE DISCUSSION has been issued at 00:05GMT on Thursday 2nd July 2009

Valid from/until: 00:05-11:00GMT on Thursday 2nd July 2009 for the following regions

Parts of (see map) SW England Wales

THREATS

Marginally severe hail; gusty winds; heavy rain; CG lightning.

DISCUSSION

Moist axis is destabilising with the approach of an upper trough - another trough is possibly later tonight/tomorrow morning. Some veering of flow in the cloud layer may promote weak mid-level rotation, perhaps enough to bring a marginally severe hail threat, along with heavy rain/gusty winds, and CG lightning.

[Neilsouth]

http://www.meteox.nl/h.aspx?r=&jaar=-3...;soort=satradar

Love the way that mcs moves eastwards , it looks like a mini fire

[SteveB]

like most people Steve I was quite surprised to see blue skies this morning...

Though Im looking at this as a positive for more energy for the thundery showers as they push up towards us later....

keeping a close eye on Sat24 infra red.....

watching the deep white lumps breaking off from the main MC...

As they try to spread north..

Hopefully there will be some growth down towards the channel in the next few hrs..

Fingers very much crossed for today.

Good to have Ian from Points West on here last night. Seemed strange watching him on the tele this morning.

[Coast]

Dew points going through the roof this morning, 18.7 DgC and rising quickly in Eastbourne!

[dogs32]

I get the impression from SKY and BBC that there will be Storms from these fronts into the afternoon and

over night...with 2 inches of rain expected...as they push East

[Lewis]

I get the impression from SKY and BBC that there will be Storms from these fronts into the afternoon and

over night...with 2 inches of rain expected...as they push East

Good morning mate,

Your nose for impressions is correct, our local forecaster paul hudson said that there will be some heavy rain pushing in tonight with some heavy storms, then tomorrow a day of heavy showers, with some "severe storms possible tomorrow night and during the early hours of saturday, feeling cooler saturday max temps 24-25c, sunday a mixed bag with some storm likely again.

lewis

[Damone]

Just woken up by a loud crash about 20 mins ago. Raining hard now, but was monsoon-like a while ago.

Is it me or does it seem like all the stuff from France is heading my way? I was sure it was supposed to be heading further east by now?

[loopydreamer]

Just woken up by a loud crash about 20 mins ago. Raining hard now, but was monsoon-like a while ago.

Is it me or does it seem like all the stuff from France is heading my way? I was sure it was supposed to be heading further east by now?

it sure is heading your way mate! you have all the action right now!

apparently it is suppose to be heading east to us later this afternoon and tonight!

[Coast]

Is it me or does it seem like all the stuff from France is heading my way?

Nope, its heading your way!