CONVECTIVE FORECAST
VALID 06Z THU 04/03 - 06Z FRI 05/03 2004
ISSUED: 04/03 05:07Z
FORECASTER: VAN DER VELDE

General thunderstorms are forecast across Ireland and the UK

SYNOPSIS

A 500 hPa trough is moving in from the Atlantic, and a developing SFC Low will position itself at the entrance of the English Channel by the end of the FCST period.
A ridge of high pressure, at the west flank of the longwave upper trough over Eastern Europe, keeps steady from Scandinavia to Italy. Under this ridge, cold air near the surface spreads out towards the Balkan, and the arctic air from the east is going to collide with the higher theta-e air brought in by the approaching SFC low on Friday.

DISCUSSION

...Ireland and UK...
With instability (GFS 12Z CAPES up to 100 J/kg) under the approaching 500 hPa trough/within a developing low sfc pressure area, showers with some thunder could develop. Since low level instability is forecast to be reasonably high, and shear will be very weak in this weak gradient zone, along with low LCLs/LFCs in places... the current synoptic setting seems to be frequently associated with waterspouts/landspouts/cold air funnel clouds. However, chances seem too low to warrant a risk category.

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