Storm & Convective Discussion - 01/03/15 onwards

[Raidan]

Been a few sferics near the Bristol channel but the rain has passed through now maybe something from other showers that come through will have to keep a eye on things.

[IanR]

just seen one flash to my north , around preston way probably

[knocker]

Strong storm affecting Italy tomorrow. Maybe a couple of feet of snow Bosnia & Montenegro

Charts courtesy weatherbell

 

[Spikecollie]

I'm liking what I'm seeing for next Tuesday in the model discussion. I'm flying to Paris on Tuesday afternoon from Manchester so it could be a good cloudspotting day...

[Stormyking]

Some interesting things going on for Tuesday by the looks of it, slack Northerly, cold uppers, surface temperatures around 9-12'c with some heavy showers showing, shows potential thunder and hail to me! Think its definatly worth keeping an eye on, I am pretty confident.

 

 

 

Edited March 21, 2015 by Stormyking

[Mapantz]

At last! A little bit of interest to look forward to.

 

Just a few picks of a bunch..

 

 

 

[Nick F]

Should be some nice convective cloudscapes this afternoon in the cool but unstable NWly flow characterised by rather steep lapse rates. We are now getting enough surface heating from the sun, albeit weak today, for convection to develop overland by the afternoon. Given moisture will be meagre and warmth lacking, not expecting anything more than the odd rumble or two and some small hail from the strongest cells. Storm forecast issued:

 

http://www.netweather.tv/index.cgi?action=convective;sess=6a455d09668cff7d8fb328266cd4f655

 

On the other side of the pond, the weather is looking a lot more lively storm-wise across the central and southern Plains today and tomorrow - a late start though for severe storms there this Spring, given the predominantly cold polar/arctic airmasses that have penetrated south across central and eastern US thus far.

 

http://www.spc.noaa.gov/products/outlook/

Edited March 24, 2015 by Nick F

[Dale Hay]

Short few minutes of hail just finishing here. Really tiny pieces.

[Summer Sun]

Lots of showers breaking out across the UK now, had a few bits of hail just before noon but other than than plenty of sunshine

 

[Spikecollie]

Absolutely stunning cloudscape here at MAN CuNbs and Towering Cumulus backlit with the sun. Had some heavy small hail earlier. I'm looking forward to seeing these clouds from up above in an hour or so, camera at the ready!

[Mapantz]

Blitzortung was showing a strike close to Bournemouth. I haven't picked anything up on my own detector, the ATD didn't pick anything up, and neither has the Astrogenic European lightning tracker. Blitzortung does have a habit of being incorrect.

[IanR]

nothing here apart from a brief light shower this morning 

[johnholmes]

Some lovely cloudscapes in this area but only one brief shower so far, a mix of large raindrops and small hail.

[Polar Maritime]

Yes as John said some nice clouds here today to, Just a sharp hail shower after lunch, Otherwise long sunny spells.

[Supacell]

As expected today was more about cloudscapes and one or two showers with a hail element to them. It is nice to see those convective clouds going up under spring sunshine again, even if it felt like winter if you weren't in the benefit of any sunshine.

Not far off storm chasing season for me now.

[Mokidugway]

Some nice anvils in the sunset ...

[Cloud 10]

Went quite dark here around 5pm with a slow moving shower of hail and sleet and a steep drop in temperature.

 

[Weather-history]

[Stormyking]

Here is one from me today, absolute amazing skies today and some very heavy showers of rain, hail and sleet!

 

[Mokidugway]

I'd wet myself for a plume in FI at the mo !!!!...

[NL]

ESTOFEX has most of the UK under a level 1 warning mainly for convective gusts.

 

 

DISCUSSION

... British Isles, Benelux, N France, SW Germany ...

Within the shortwave trough the advection of cold air of polar origin and thus the cold front is expected to pass trough Ireland, S Great Britain, Benelux, N France and SW Germany. CAPE is forecast to be marginal (100-200 J/kg) but it will occur in the highly sheared environment. Although free convective layer will be shallow, both very high 0-6 (40-50 m/s) and 0-3km (20-25 m/s) vertical wind shear indicate that convection may organize into linear feature and create risk for the severe wind gusts of convective origin. Significant mid and low level air flow according to NWP data may provide convective gusts up to 25-30 m/s, if convection will be involved, it is possible that these gusts may be even stronger. Increased LLS exceeding 15 m/s, 0-1km SRH ~ 150 m2/s2 overlapping with marginal instability and favorable QG-forcing create also risk for the significant tornado occurrence. Certainty to the lightning activity is decreased mainly due to relatively warm cloud tops, shallow free convective layer and low thermodynamic instability. Therefore only 15% probability for the lightning is issued. The highest threat for the severe weather occurrence and linearly organized storms will fall on British Isles between 0900 and 1500Z

http://www.estofex.org/

 

 

 

[poseidon]

Torro convective discussion issued:

 

http://www.torro.org.uk/site/forecast.php

 

Valid from/until: 07:40 – 17:00GMT on Sunday 29th March 2015 for the following regions of the United Kingdom & Eire:

N and mid Wales

Midlands

E Anglia and Lincs

Parts of SE England

THREATS

Isolated tornadoes; wind gusts to 60mph; CG lightning

SYNOPSIS

A diffluent upper trough at the eastern end of a powerful Atlantic jetstream will continue to sharpen a frontal wave across the southern half of the British Isles. Models suggest modest CAPE developing within the warm sector and high resolution models suggest the development of a line or lines of precipitation along the cold front. Strong low-level wind shear suggests that small waves may develop along this line /misocyclones/ which may locally enhance the strong wind threat, and provide a small risk for isolated tornadoes. Instability may be enough for a few CG lightning discharges too.

 

[Supacell]

A line of intense precipitation across the north Midlands now with some sferics west of Derby. Brought a brief spell of heavy squally rain here with gusty winds.

[Mokidugway]

Some heavy ppn on that line echo but as yet sferics ..detected locally though ..

Edited March 29, 2015 by Mokidugway

[poseidon]

Plenty of sferics appearing now.