Forecast for Thurs...
Storm Forecast
Valid: Thu 05 May 2011 06:00 to Fri 06 May 2011 06:00 UTC
Issued: Wed 04 May 2011 21:54
Forecaster: GATZEN
British Isles
A quite warm and moist air mass advects into the British Isles with southerly low-level winds to the east of an Atlantic low pressure system. Latest Valentia sounding indicates nearly neutral lapse rates that will easily allow for weak CAPE due to daytime heating. Latest model output indicates weak instability over the southern and western British Isles on Thursday afternoon. Sea breeze convergences are forecast to assist initiation that will become more likely near a mid-level jet streak pointing towards Ireland. The severe threat is forecast to increase in the western parts where rather strong south-westerly winds are expected. Especially in the evening hours models suggest increasing low-level vertical wind shear (SRH 100 mē/sē in the lowest kilometre) that will overlap with some weak CAPE. This may support tornadoes, and some events are not ruled out. Limiting factor will be the rather weak low-level convergence, and a level 1 threat is not forecast. Storms are expected to weaken after sunset.
