Uk Convective General Discussion & Forecasts - 2012

[kold weather]

Right well here is a new thread for a brand new year. This thread is for general discussion of convective weather in the UK!

Here is a warning issued by Nick earlier today:

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

Post about any storm related discussion!!

[DAVID SNOW]

Right well here is a new thread for a brand new year. This thread is for general discussion of convective weather in the UK!

Here is a warning issued by Nick earlier today:

http://www.netweathe...onvective;sess=

Post about any storm related discussion!!

Insane 5 minutes here as the Squall line passed through.

[Mike Storm]

me too was mad... horizontal rain 38 knot gust..... glad i was indoors

[kold weather]

Yes the squall line was very intense, gave a 5 minute period that was pretty mmuch what you'd expect in a Tropical Storm, lashing rain and probably 35-40kts sustained winds with it. Pretty impressive!

[Coast]

I see we had a possible tornado in Clacton yesterday:

Tornado

Clacton-on-Sea England

United Kingdom (51.79 N, 1.16 E) (+/- 1 km)

03-01-2012 (Tuesday) 14:57 UTC (+/- 1 hrs.)

Based on: information from a newspaper report, a report on a website

Occurring over: land

The intensity rating was based on an eyewitness report of the damage.

Accompanying weather: heavy rain.

Described as a 'mini tornado' - streets flooded and trees uprooted

http://www.clactonandfrintongazette.co.uk/news/north_essex_news/9449384._Tornado__rips_through_town/

Report status: as received (QC0)

+ Hainault:

Tornado

Hainault England

United Kingdom (51.61 N, 0.10 E) (+/- 1 km)

03-01-2012 (Tuesday) 14:18 UTC (+/- 5 min.)

Based on: information from a newspaper report, a report on a website

Occurring over: land

The intensity rating was based on photograph(s) and/or video footage of the inflicted damage, an eyewitness report of the damage.

Trees uprooted, roofs damaged; further information will follow (T.Kühne)

http://www.london24....tness_1_1167561

report status: as received (QC0)

and many more reports associated with the storm

http://www.essl.org/...n/eswd/eswd.cgi

[kold weather]

Very interesting, of course in this type of set-up you always have tp be careful to assume they are both tornadoes, could easily have been a very powerful downburst during the peak of the Squall Line.

Still there was some decdnt shear yesterday so I suppose a couple of weak tornadoes would be plauseable with such a strong squall line,

[DAVID SNOW]

I see we had a possible tornado in Clacton yesterday:

+ Hainault:

and many more reports associated with the storm

http://www.essl.org/...n/eswd/eswd.cgi

Am about a mile or so from there,would back up my post lol. Hainault that is.

[Stuart]

Last Updated: 21:31 Friday, 6th January 2012

Valid: 00:00 Saturday, 7th January 2012 - 23:59 Saturday, 7th January 2012

Areas Affected:SLGT: Orkney and Shetland

Synopsis:While a ridge builds to the west of the United Kingdom, a strong northwesterly flow across the country, and in particular the North Sea, will allow cold mid-levels to spread southeastwards.

Discussion:

The focus for any significant convection is across Orkney and Shetland due to lower geopotential heights and steeper lapse rates given colder mid-levels. Such mid-levels atop relatively warm SSTs will generate 400 J/kg CAPE, allowing scattered showers to develop with a low risk (20%) of lightning, given ELTs <-30C. Also given the atmospheric profile, some small hail is likely in some showers.

During daylight hours, warming mid-levels associcated with the approaching ridge and subsequent rising geopotential heights will confine the focus for any significant convection to Shetland, but even here by the end of the afternoon the lapse rates become too unfavourable to support lightning activity.

Nevertheless, convective gusts >50kts are possible, although a lack of any significant DLS inhibits the risk of tornadic development.

Showers will decrease in number through the evening as the ridge continues to build and become established.

http://ukasf.co.uk/storm-forecasts/146

[Lauren]

I'll be honest, I have no idea what they are on about half the time in the model discussion thread and don't want to keep asking in there, but basically:

What are they all getting so excited about, what is on the GFS?

[Robbie Garrett]

Some nice little CB's going across London at the moment, little shower. Awhhhh so cute!!!

[Coast]

Some slight interest on the horizon around the 25th Maybe?

[Stuart]

Thanks Coast I cross my Fingers

[Coast]

Thanks Coast I cross my Fingers

Well the usual comments apply Stu at this comparatively long range, but it does look a little bit more active on the convective front from GFS, I'll keep an eye on it as the week progresses.

[Coast]

Not sure about the 25th (being a week away and all) but tomorrow sees slight potential for weak thunderstorm activity across much of Scotland (perhaps NW England as well), particularly towards the west, as cold air at 500mb surges east during the afternoon period, steepening mid-level lapse rates.

Indeed I believe this was the case earlier too!

[Liam J]

Some real lively showers rattling through here, Hail stones and sleet mixed in with gusts touching 50mph during the showers.

Radar looking interesting over the north and north west.

[Coast]

Might be slight potential along what is looking like an sharp (ANA) cold front transferring generally eastward across the country during Wednesday evening and into the early morning period on Thursday.

I'm seeing small signs more for Thursday/Friday at the moment:

Just an aside, look at the potential for action in Norway!

[Coast]

ESTOFEX first on the block for possibilities today:

Storm Forecast

Valid: Wed 25 Jan 2012 06:00 to Thu 26 Jan 2012 06:00 UTC

Issued: Tue 24 Jan 2012 20:34

Forecaster: PUCIK

No threat levels have been issued

SYNOPSIS and DISCUSSION

Main macrosynoptic features at midlevels will be an extensive mid level low centered over the eastern part of Central Europe, a ridge over Western Europe and a deep trough over the Atlantic that is forecast to affect British Isles in the evening hours. Generally speaking, eastern half of Europe experiences an influx of arctic continental airmass from northeast (its source being widespread Siberian high), which is expected to advect southeastwards behind the cold front of the surface low affecting the Aegean region.

Conditions will be generally too hostile to support any serious chances of well organised and strong DMC, precluding issuance of any threat level. Nevertheless, three areas might experience some thunderstorm activity.

Coastal areas of western British Isles

In the high lapse rate polar maritime airmass behind the cold front of the deep surface low, banded convection is forecast. Few lightnings might be recorded, but generally only weakly electrified convection is forecast due to very dry airmass (mixing ratios below 3 g/kg).

Here are a couple of charts to follow that up:

Lapse rates approaching the Western edges of the UK and Ireland later:

and the rain:

Shear through central areas:

Helicity and gusts through the North Sea and out to Norway:

Potential for a few isolated t-storms in the early hours of tomorrow:

and on into the day for SW areas:

[Jane Louise]

Ahhh, so a little hail and thunder has been forecast tomorrow for the SouthWest!! Probably applies more to the coasts! Interesting day whatever may happen.

[Coast]

Ahhh, so a little hail and thunder has been forecast tomorrow for the SouthWest!! Probably applies more to the coasts!

Not this one Jane, you might be in the firing line tomorrow!

[Jane Louise]

Not this one Jane, you might be in the firing line tomorrow!

Shhhhush :winky: Well, I do have a 30% chance I suppose I reckon it's more Cornwall and Devon that may get a flash or two. Gloucestershire probably nothing as usual Lol. A bit of radar watching tomorrow is on the cards just in case.

[Aaron]

Might be some thundery showers ahead of this cold front.. let's wait and see

[Jane Louise]

Here is the latest from Uk weatherworld courtesy of Tony gilbert. and I'm in this one Lol

9.15pm Weds

Slight Risk of Convective Showers with Moderate Hail Falls. Possibility of Sferics. Western Eire & Western UK regions 09Z-21Z

Certainly a low level outlook for severity, though worth a mention. Post frontal troughing expected to gain pace by early morning with multiple tall cumulonimbus observations expected for the regions as per map below. Given the exceptional height falls and low freezing level we will see numerous isolated pockets of hail showers with further risk of isolated sferic activity. Supporting vertical; shear looks rather weak though we should primarily expect pulse type activity. There is also some minor scope for partial separation of updraft to outflow around the Bristol region late in the day.

Whilst we can expect to see tall glaciated cb development, updrafts will nevertheless be comparatively weak. In short, the tall cloud tops will be achieved at a rather slow pace. In any case certainly a good day for that classic thunderhead photo shot!

( Map on Uk weatherworld)

http://www.ukweatherworld.co.uk/forum/index.php?/topic/89091-convective-outlook-thurs-26th-jan-12/

[Purplepixii]

Got everything crossed for you Jane!

[Jane Louise]

Got everything crossed for you Jane!

Thanks Sarah, maybe it'll be my first for 2012 after all 2012 is going to be a good year you know. :winky:

[Aaron]

Can't be any worse then 2011