Uk General Convective Discussion & Forecasts, 13th March 2013 onwards

[Paul]

Some decent storms ongoing in southern Scotland this pm.

 

 

Latest radar / lightning

http://www.netweather.tv/radar

[Cloud 10]

Had a decent hail shower and a couple of rumbles of thunder about half an hour ago.

 

[Thundery wintry showers]

A cumulonimbus that passed to the north-east of here at about 5:20pm gave three distant rumbles of thunder, also had a couple of hail showers, though the majority of the activity has been further north.

[Stuart]

ok last update from me

 

Synopsis:

Upper trough weakens substantially as ridging/warming aloft approaches from the northwest. Nonetheless, another day of convection is expected across southern Britain where coldest mid-levels will be present.

 

Discussion:

... C/S ENGLAND ...

Upper low will slide slowly southwards across the highlighted areas during the day, coupled with cool mid-levels (typically -28C at 500mb). Rising LSTs will once again generate (rather weak) 100-300 J/kg CAPE, with scattered showers and one or two pulse-type thunderstorms developing. ELTs down to -20C and 500mb-SFC dT ~40C could allow some sporadic sferic activity, but this is unlikely to be widespread with only a 15-20% chance at any given location.

 

DLS is weak under the trough axis, stronger across the Midlands, so convective is likely to be poorly organised, but given cold air aloft hail is once again likely in many of the showers, perhaps locally up to 1.0cm in diameter in any stronger cores. Cloud bases will also be quite high, so a fairly photogenic day is likely. Increased ridging/warming aloft will gradually cause showers to decay during the late afternoon/evening hours.

 

 

http://ukasf.co.uk/storm-forecasts/238

[Convective]

Well nothing here today! Although.. one hefty hail shower this morning which left a small covering of hail. Mostly small stuff (<0.5cm). The sea around us kills everything this time of year and especially with it being colder than usual this year! Autumn always puts on a good show around the Irish sea when the sea temperature exceeds the air temperature.

 

Anyway.. I ain't seeing too much happening tomorrow! 

 

[Coast]

A few small peaks coming up in the regional free atmosphere charts, but not enough to get too excited about just yet:

 

 

 

 

Actually looking quite quiet down South for a few days

[Convective]

Reports of thunder near the east midlands recently

[Karl83]

Came back from work yesterday and was impressed with the clouds so thought I'd share this.

 

[Supacell]

Blustery shower passing over Belper now with some sleet mixed in.

Edit: looking again it is probably soft hail.

Edited April 27, 2013 by Supacell

[Convective]

Expecting a few of them showers dotted across the Midlands to go bang any time soon.

[BlueHedgehog074]

Had recently got attacked by these bad boys!

The shower did start mostly as rain, although gradually within time, the rain become more and more hail-o-fied.

[Staffordshire]

Heavy shower passing here with gusty winds

[Lynxus]

really strange hail the last few days.

 

It doesn't bounce. It simply splatters like wet snow.

 

very cool

[galacticwarrior]

Just heard thunder.

Hail falling and rain lashing onto windows

[Sprites]

 look at this  for may 10th

[Panayiotis]

Well nothing here today! Although.. one hefty hail shower this morning which left a small covering of hail. Mostly small stuff (<0.5cm). The sea around us kills everything this time of year and especially with it being colder than usual this year! Autumn always puts on a good show around the Irish sea when the sea temperature exceeds the air temperature.

 

Anyway.. I ain't seeing too much happening tomorrow! 

 

Over the last couple days your predictions have been spot on, very well done! If you dont ask me asking but what models do you use to depict the areas are at most risk?

[Convective]

Over the last couple days your predictions have been spot on, very well done! If you dont ask me asking but what models do you use to depict the areas are at most risk?

 

Thank you very much! I use charts available on Netweather. Doesn't seem very professional but I go mainly by forecast for where it's going to be sunny and what the wind will be like from forecast sites such as here and BBC/ Met Office. I combine that with CAPE/ LI charts available here! Thanks again!

[Convective]

Gone very dark here suddenly and cloud bases are low! Heavy showers in the area too! 

[Stuart]

look like it scotland turn this year

 

Synopsis:

An upper trough will migrate eastwards across northern Britain behind a surface cold front/occlusion complex. In the post-frontal environment, a day of convective showers is expect.

 

Discussion:

... SCOTLAND ...

Cold mid-levels will overspread the highlighted area in association with the passage of an upper trough, steepening lapse rates and allowing 100-300J/kg CAPE to be generated in response to rising LSTs. Consequently numerous showers are expected to form, with the chance of one or two pulse-type thunderstorms, particularly across N/NE Scotland where best instability will be present coupled with the base of the upper trough.

Some 20-30kts DLS will allow cells to become fairly-well organised and long-lived. Hail is likely in many showers, perhaps locally up to 1.0cm in diameter in any stronger cores. There are some indications that organised convection may develop over Shetland/Orkney and environs between 03z-07z, bringing an increase chance of lightning here. However, there remains some uncertainty as to how well-developed this will be, and for now we remain with a SLGT threat level.

 

 

http://www.ukasf.co.uk/storm-forecasts/239

[Convective]

Nice one Stuart. I have a feeling a few showers could drift into Northern Ireland and into parts of northwest England later on in the morning and early afternoon and here they could be accompanied with some small hail and a rumble or two of thunder. Nothing too spectacular though.

[Mark Neal.]

Had a proper hail shower on Saturday around 1pm, came down hard!

[AWD]

Looks like a continuation of quiet, benign weather to come. Has there ever been such a quiet, slow start to the convective season?

Struggled to get any shower activity IMBY this month, let alone anything more.

[Convective]

Looks like a continuation of quiet, benign weather to come. Has there ever been such a quiet, slow start to the convective season?

Struggled to get any shower activity IMBY this month, let alone anything more.

 

Me too! Not a fart! All seems to of been extreme north or extreme south so far this year!

[Coast]

Looks like our French cousins get all the action over the B/H weekend, trip across the Channel anyone?

 

 

 

Paris looks like the place to be:

 

[Karl83]

I look to Sunday Monday & Tuesday next week for something.