TORRO TORNADO WATCH 2013/005
A TORNADO WATCH has been issued at 09:15GMT on Sunday 20th October 2013
Valid from/until: 09:15 – 21:00GMT on Sunday 20th October 2013, for the following regions of the United Kingdom & Eire:
Parts of (see map)
Much of central and southern England
Tornadoes; Hail 20mm diameter; wind gusts to 55mph; CG lightning
Deeply unstable rPm airmass covers much of the British Isles. Several vorticity maxima are rotating around a deep low, which is situated to the west. One such maxima has produced an area of showers and thunderstorms, which caused damage, possibly tornadic, around Hayling Island. Another max is in the western English Channel – it is not completely clear where the large area of showers and thunderstorms will go, but it looks like crossing at least parts of SE and perhaps Central Southern England today – its northern extent is uncertain.
Other showers and thunderstorms are present or will form to the north of this. All of this activity is embedded within a flow regime marginally supportive of rotating updraughts – low LCLs suggest that further tornadoes are possible with any stronger updraughts – the highest risk appears to be close to southern and western coasts, but diurnal heating should expand the risk well inland for a time today.
Other convective activity is present across Eire/N Ireland, and may also move into/develop across N England/S Scotland. Whilst local severe weather cannot be ruled out, the risk seems to be lower than further south. However, the northern extent of the tornado watch box does not come with high confidence.