TORNADO WATCH 2010/004
A TORRO TORNADO WATCH has been issued at 2315GMT on Thursday 19th August 2010
Valid from/until: 23:15- 08:00GMT on Thursday 19th/Friday 20th August 2010 for the following regions
Parts of (see map)
Eire
N Ireland
S Scotland
Isle of Man
THREATS
Tornadoes; wind gusts to 65mph; CG lightning; heavy rain
DISCUSSION
Strong upper low is moving NE to the west of the British Isles, with an associated short-wave crossing the watch area. A broad, very moist tropical maritime airmass exists at low levels, behind a warm front, which is currently moving through Scotland. A cold front to the west of Eire/N Ireland will start to move eastwards later tonight, and tend to surge eastwards later. Instability exists in the warm sector, partially aided by mid-level cooling associated with the upper trough. Thunderstorms are occurring already across SW Eire, and further showers and a few thunderstorms are likely overnight. Strong deep layer shear (40-50 knots) should promote cell organisation, perhaps supercells. Low-level shear of 25-30 knots suggests low-level mesocyclones are possible. Tornadoes and damaging winds are possible across the area, and the magnitude of the low-level shear coupled with a very moist boundary layer suggests a small chance of a stronger tornado.
The risk will extend into Scotland through tomorrow morning, and a new watch is likely to be needed tomorrow morning.
Forecaster: RPK.
