Tornadic Cold Front Potential - March 3rd/4th (UK)

[martinastro]

This is from the UKWW. Will be keeping an eye on this when more info is available closer to the time. At the moment this applies to both Ireland UK....

Various models hinting at possibly very volatile weather across the UK Tuesday 3rd - Wednesday 4th March.

Large depression becoming anchored to northwest of UK. Fast moving wave depression moving around southern flank of low on these dates hinting at rapidly deepening near the UK with cold air following rapidly. Cold front expected to accelerate as wave depression deepens under left exit diffluence with consequent 'scoop-up' of mild, moist air ahead, with cold air undercutting with front perhaps developing 'ana' characteristics.

Likely to lead to 'squall line' conditions with the possibility of development of short-lived small tornadoes.

Cautionary notes:-

1, GFS does not show 'confluent trough'.

2, Sea temps are colder than average just now, so low level instability may be limited.

3, We are statistically entering the time of year that is least tornadic across the UK.

One to watch.

[Tyler]

Hey martin, Im interested to see the site you use for models. The GFS is a Global forecast system, yet I have never seen maps for the UK, europe, or anywhere else. Could you post the link you use? I am interested to see the difference of dynamics for storms in NI vs NE. Thanks 

[martinastro]

Hey Tyler, I actually got that info from the Ukweatherworld forum (It's one of the other places I'm a member of) so I can't take any credit for forecasting this myself. The above was an early forecast by the experts on there who work for TORRO and elsewhere. They use several different models and compare the results. I look at the GFS charts for long range but for short range forecasts I make life alot easier for for myself by using the lightning wizard convective maps for t-storms and funnel/tornado risk potential for my own area. I have found these maps to be very useful....

http://lightningwizard.com/maps/

I also use the netweather GFS data....

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

[martinastro]

TORRO CONVECTIVE DISCUSSION 2009/003

A TORRO CONVECTIVE DISCUSSION has been issued at 1610GMT on Tuesday 3rd March 2009

Valid from/until: 1610 to 0300GMT on Tuesday 3rd/Wednesday 4th March 2009 for the following regions of the United Kingdom & Eire:

S Wales

SW England

Cent S England

SE England

E Anglia

S Midlands

Channel Is

THREATS

Wind gusts 50-60mph; isolated tornadoes; isolated CG lightning; hail; heavy rain.

SYNOPSIS

Deepening Atlantic low will move NE through the Irish Sea this afternoon and through Scotland tonight, with its cold front crossing England and Wales. A strong rear-inflow jet is progged on the models to push the cold front across southern parts this afternoon and overnight. This is already causing line convection to the west of SW England, and this should continue east overnight. Descent of the strong rear-inflow jet should allow some strong wind gusts, and this, along with strong low-level shear just ahead of the line, could instigate misocyclone development, enhancing wind gusts, and also bringing a tornado risk.

Forecaster: RPK.