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

[Evening thunder]

Sefrics now being detected in the south with 19 in the last 30 minutes: http://www.netweather.tv/index.cgi?action=lightning;sess=

 

Heading towards my uni so will probably hit there when I'm at home lol

 

Edit: oddly enough 5 minutes later it now seems to have changed to 11 strikes on that link in the last hour

Edited April 18, 2013 by Stormmad26

[Andy Bown]

Lol yes Storm Mad, not 5 mins after I posted earlier there was thunder here!

[Bluebreezer54]

Torrential cloudburst with hail here. Lasted less than 5 minutes with one sferic picked up on an am radio, and intense wind.

[Tim Bland]

Nice beefy hail shower over Stevenage covered everything in 2 mins

[Paul]

A few storms rumbling their way across southern England currently:

http://www.netweather.tv/index.cgi?action=radar;sess=

 

 

 

 

 

 

[Bluebreezer54]

A few storms rumbling their way across southern England currently:

http://www.netweather.tv/index.cgi?action=radar;sess=

 

lightning.png

And very welcome they are too !!

[Supacell]

A small storm around Manchester about an hour ago by the looks of it too. Despite the very low risk outlook it could end up being the most active day so far this season for storms - although that wouldn't be too hard to achieve.

[Convective]

Well after a mild, breezy, sunny day here the sky has gone very ominous.. note that these photos aren't edited at all

 

 

 

 

[Polar Maritime]

The Midlands could get a few rumbles this afternoon..

[Convective]

Well after a brief settled spell, Friday onwards currently show up as being more active convection wise.

[Panayiotis]

I would imagine we would see some storms from this?

http://modeles.meteociel.fr/modeles/gfs/runs/2013042218/gfs-0-174.png?18

[Convective]

Quite a bit of energy around on Friday as well as a trough moving over through the afternoon

[Coast]

Not really up for any in-depth stuff at the moment, but early indicators are favourable for Eastern Scotland and NE England on Friday afternoon according to GFS output:

 

 

 

 

[Stuart]

Synopsis:

A slow-moving waving cold front will continue to migrate erratically southeastwards across England and Wales. In the post-front environment, significant cold air advection will occur across northern Britain as an upper longwave trough gradually approaches from the northwest.

 

Discussion:

... N + W SCOTLAND ...

Cooling mid and upper levels will steepen lapse rates throughout the day, and coupled with LST/SSTs of 7-8C, will generate widespread scattered showers and a few thunderstorms. CAPE is rather skinny/weak (couple hundred J/kg) given quite dry air, but with SFC-500mb dT around -43C and ELTs locally -30C, some cells should become electrified by the afternoon, especially in the far north and west of the SLGT area as instability continues to increase throughout the day.

Strong jet aloft provides signficiant DLS, especially at first, so convection is likely to be fairly well-organised at times, and may tend to form bands as various lobes of vorticity rotate around the upper low. Dry, cold air will result in quite high cloud bases (so skies should be quite photogenic) and this will limit severe weather somewhat.

Given cold air aloft, many showers are likely to produce hail in any strong cores, perhaps up to 1.0cm in diameter locally, which may cause some local temporary travel disruption.

 

http://ukasf.co.uk/storm-forecasts/236

 

[Coast]

The threat of thunderstorms has remained mostly to the North West of Scotland tomorrow and has diminished a little bit according to GFS latest:

 

[weatherobsuk]

Looking at the meto surface pressure forecast for tomorrow there is a trough set to move out from NW Scotland late overnight and into the Irish Sea by tomorrow afternoon, given the vectors anything that initiates looks to be pulled away from that trough and the cells to move into Cheshire and the North Wales coast.

 

Perhaps one or two making their way down into the south pennines, but overall with clear skies and CAPE there will be good opportunity for anvil photography if we get any beefy TCu's moving on through.

[Convective]

Here's what I'm going along with for tomorrow

 

Edited April 25, 2013 by Convective

[BlueHedgehog074]

Quite looking forward to the sunshine and shower setup tomorrow, and wondering how big and heavy each possible shower will be.

If it's okay to ask this here, what would you need to look out for to determine whether the showers fall as hail or not in these convective setups? I mean I kinda know you need some sort of a cold air-mass above, but is it the actual 850 hpa upper temperatures that have an affect on this? (sorry, I know I should have probably asked this in the Learners area).

[Stuart]

Synopsis:

A cold front will clear the South East corner early on, introducing a much colder, showery airmass across the British Isles. An upper trough will slowly migrate southeastwards across northern Britain in this cold air. Greatest probability of lightning from convection will be within the base of this trough as it coincides with peak daytime heating.

 

Discussion:

.. S + W SCOTLAND, N ENGLAND, N IRELAND, NW WALES ...

Convection is likely to be present from daybreak underneath the upper trough across NW/W Scotland. Elsewhere it is expected to be dry at first, but rising LSTs coupled with cold air aloft will generate some weak CAPE (100-300 J/kg CAPE), allowing widespread scattered showers to form. The passage of the base of the upper trough coupled with diurnal heating will bring the greatest potential for lightning by the afternoon across C/S Scotland and E Northern Ireland (but even here is only considered 25-30% probability, with only sporadic/isolated activity expected).

Shear is weak, so convection is likely to be disorganised with 'pulse-type' storms most likely. Given cold air aloft, some showers/storms are likely to produce some small hail, perhaps locally up to 1.5cm in diameter which may cause some minor temporary disruption on roads etc.

 

http://www.ukasf.co.uk/storm-forecasts/237

[Coast]

Current SatRep:

 

 

Small amounts of ML CAPE over NW Scotland and Wales:

 

 

Surface CAPE a little stronger in those areas:

 

 

 

 

Lapse rates up over much of the UK:

 

 

Shaded area seems to be the place for any rumbles of thunder today:

 

 

[Eye to the sky]

Just driven through two sharp hail showers between Belper and Duffield.Very threatening skies all around.Sun is out again now,so hopefully things will get going later!.

[Supacell]

Hailstones near to Mansfield a few mins ago.

[Andy Bown]

Lovely clean convective sky in Wiltshire region now with TCu building into Congestus and the makings of a few CBs in the sky to the N/NW which correlate well with showers moving in from the Bristol Channel.

[Arnie Pie]

 

Had a shower with graupel pass over here a short while ago. Indeed, nice looking skies today- showers rather high based allowing for good views of rain curtains/hail shafts.

 Can see just this across Barr Beacon...and heading your way

Photos later

Edited April 26, 2013 by Arnie Pie

[Arnie Pie]

From this morning....Hail and bubbling clouds across the NW of the city