TORRO TORNADO WATCH 2014/009
A TORNADO WATCH has been issued at 0720GMT on Wednesday October 8th 2014
Valid from/until: 0720 – 2000 on Wednesday October 8th 2014, for the following regions of the United Kingdom & Eire:
Parts of (see map)
Much of Wales
Central and southern England
Humberside and Lincs
Tornadoes; hail to 25mm diameter; wind gusts to 60mph; CG lightning
Vertically-stacked low pressure just west of southern Ireland will drift slowly eastwards. A moist airmass is spreading into the watch area, with a short-wave trough crossing SE England at the moment. Another short-wave will move in from the south-west through today.
The initial trough is bringing a large area of rain with embedded thunderstorms across SE England at the moment, with heavy showers approaching SW England and Wales, associated with the second trough.
Vertical shear is strong across SE England at the moment, and the initial activity poses at least a low risk of strong wind gusts and perhaps an isolated tornado, especially near the south coast. As the morning progresses, modest diurnal heating will generate a few hundred J/Kg of CAPE amidst fairly strong vertical shear /0-6km shear around 40 knots, and 0-1km shear of 25-30 knots/. Organised convection is possible, mainly in the form of lines, but supercells cannot be ruled out. The strong low-level shear and low LCLs suggest a risk of one or two tornadoes too.