Uk Convective General Discussion & Forecasts - April 2012 Onwards

[NO LONGER POSTING]

Shower after shower after shower here...Some pretty hefty ones 2 1 rumble of thunder this morning

[NO LONGER POSTING]

Is all that lot up North going to spin back down on itself

[Bluebreezer54]

Certainly chucking it down at Stamford Bridge !!

[Hodgheg]

Raain Hoping for some storms tomorrow, looks good on the charts. Allways seem to miss here though.

[NO LONGER POSTING]

So where is it game on for tomorrow then ?

[Aaron]

Raain Hoping for some storms tomorrow, looks good on the charts. Allways seem to miss here though.

I concur. Hoping for some tomorrow.

[Arnie Pie]

Spin or just an illusion

http://youtu.be/G5vYV5lGWGM

[Eskimo]

Eskimo, when was that video shot?

August 2nd 2011

[Nick F]

Storm & Convective Forecast - Issued 18/04/2012

Valid: 19/04/2012 00:00 - 20/04/2011 00:00

Headline: ... THERE IS A RISK OF THUNDERSTORMS FORECAST...

Synopsis

Slow-moving upper and collocated surface low will reside across eastern England on Thursday, with an unstable and showery circulation.

EIRE, ENGLAND, WALES and S SCOTLAND

The instability created by lift near troughs/wrap around occlusions in the low pressure circulation across the UK will see bands of showers from the word go Thurs morning across many areas ... and once again, diurnal surface heating in the sunny spells beneath cold air aloft will generate a few 100 j/kg or more of CAPE by early afternoon ... which will allow scattered thunderstorms to develop. Hail and gusty winds will again accompany any storms. Deep layer shear will be rather weak, though storms may organise along troughs/wrap around occlusions in low pressure circulation and as storms/showers will be slow moving and tend to merge - there is a risk of localised flooding. Backing of sfc winds on the SE/E side of low will tend to increase low-level wind shear across E/SE England ... so a weak tornado cannot be ruled out with stronger storm updrafts.

[Eskimo]

VERY good potential for the East tomorrow.

[DubWeatherAddict]

Best Mammatus Clouds ive seen in a long time around here.

More shots here from today including some great anvils .

http://www.flickr.com/photos/41948286@N02/with/6945617110/

[Costa Del Fal]

VERY good potential for the East tomorrow.

And for Central, Southern and some Northern parts too. However if the NMM is right then the East might not see much.

Edited April 18, 2012 by Blizzards

[BlueHedgehog074]

Spin or just an illusion

http://youtu.be/G5vYV5lGWGM

Nice vid.

Kinda looks like there was a bit of rotation their with that low level cloud base at the start.

[davehsug]

Dull, cold & damp all day here. Been a bit of a letdown this last week. Seen lots of heavy stuff going to our north over the peak district, but no thunder here. Looking at the forecast for the next few days, looks like most of the good stuff is for the south & east again, but we live in hope!

[Snowangel-MK]

Has anyone been under these strikes today then?

So close.....and yet so far - and on a day when I was too busy to go and chase as well

[VillagePlank]

Estofex,

London/SE,

A good chance of thunderstorms in the far SE, today, I reckon. KI shows a moderately convective profile, LI supports this. CAPE gives enough energy, and TT tends towards vigorous thunderstorms where they form. Trigger likely to be surface heating, and, I think, t/storms are more likely towards 4-7pm rather than late morning, early afternoon.

Happy Hunting!

M

Edited April 19, 2012 by Boar Wrinklestorm

[Coast]

UKASF:

Forecaster: Chris

Last Updated: 2012-04-18 23:28:00

Valid: 2012-04-19 00:00:00 - 2012-04-19 23:59:00

Areas Affected:

Wales, much of Eire, England (excluding the SW) and S Scotland.

Synopsis:

A very slow moving, mature area of low pressure will continue to dominate the synoptic pattern across Britain during the day. The surface low will be centred over East Anglia through much of the day with the remnants of an occluded front located across northern England. Various troughs will also continue to be within the circulation of the low and most likely be the focal point for any more enhanced convection.

Discussion:

The mature area of low pressure will allow for broad area of ascent / instability across much of Britain, however a lot of cloud will continue to be within the circulation inhibiting surface insolation (warming at the surface due to incoming solar radiation). This may limit the potential of strong enough convection to produce thunderstorms (much like on Wednesday). However, with that said, the 12z NAE suggest with a weaker occlusion that convection/mixing may be a little better on Thursday allowing for more breaks in the cloud during the afternoon. Surface temperatures look to be about 2C warmer than on Wednesday as well. Away from the occlusion, especially across Cen and S England CAPE values may approach 400j/kg. Cold air aloft with 500mb temperatures around -29C and ELTs around -45C should mean that convection will reach high enough for some thunder. Very limited DLS within the mature low will mean that sustained convection is unlikely, and if anything convection remnants may increase cloud cover again, reducing further convective potential.

The interesting thing is that there will be some very limited LLS (around 20kts) in southern England. This combined with some convergence boundaries associated with varying winds around the low centre could mean that any stronger updrafts have the potential of producing some brief funnels. Both the 12z GFS and 12z HIRLAM indicated a above average "spout index" which combines low level CAPE and low level shear (generally in the lowest 1-2km). This could mean that even convection that doesn't produce lightning has the potential to produce some funnels. The highest probability of these seem to be across Lincolnshire, Norfolk and Suffolk (especially coastal convergence boundaries). So keep an eye to the sky with any "better" convection and a camera to hand just in case!

Main threats will be locally heavy downpours and small hail (generally less than 1cm).

Nothing else from the other dedicated storm sites just yet other than the ESTOFEX map, but TORRO issued a forecast quite late yesterday for the day so I will keep an eye on them later

Here's an overview of some charts for the day:

Strongest chart for lightning I've seen for a couple of weeks:

Looking better for the SE later today, I'm just a tiny ickle bit excited......

Liking the thought of what might develop on the Southern side of the low later this afternoon:

Another day to watch the skies and the radar!!!

[Evening thunder]

Not amused how the convective potential keeps being moved away from the SW every day.. while at night it increases around the coasts at times suggesting if that was in the day there would be far better CAPE over the land.

[Jane Louise]

Morning all

I'm quite excited for today as all the charts are looking good. The Met Office has kindly put Gloucestershire down for some hail and thunder.

Sunshine and showers for many areas, with the heaviest and most frequent showers in Gloucestershire and Wiltshire, where they may be thundery with hail.

http://www.metoffice.gov.uk/weather/uk/sw/sw_forecast_weather.html

Estofex almost has the thunderstorm symbol right over me too so I feel this could be the day.

[Coast]

Custom SkewT for Eastbourne best this week so far!!!

Benny Hill much the same!!

[SteveB]

Not holding out much hope for my area today. I think I am to far West to see anything.

Good luck to everyone else though.

[Nick F]

After just rain showers yesterday here, infact there wasn't that many storms over England & Wales yesterday (Nern Scotland had more) - I am hoping for a bit more today.

Unfortunately there is rather a lot of cloud cover this morning away from the SW, which will hamper solar heating needed for storms if it doesn't clear:

UK Vis Satellite: http://www.west-cheshire.ac.uk/weather/msgvis.asp

[chionomaniac]

Agree with that Nick.

Is anyone away from the SW seeing sunshine?

[Coast]

A potentially unsettled and stormy period coming up across the country;

[Lynxus]

Wow, theres some awesome agreement between a lot of charts here.

Its always good that estofex have a warning. ( Even though it rarely come off ) But with estofex and other systems all saying the same. Then its a good day to watch

Sun is trying to poke through. Just need some of this cloud to shift... We will see.