Extended Forecast
Valid: Tue 19 Feb 2008 06:00 to Wed 20 Feb 2008 06:00 UTC
Issued: Sun 17 Feb 2008 19:49
Forecaster: TUSCHY

Dominant blocking pattern gradually comes to an end as geopotential heights reduce over most parts of west-central Europe.This decaying high pressure area is framed by two longwave-troughs, one established over eastern Euope and the other one west of Ireland. Stable conditions prevail area-wide and the stable stratified atmosphere only gets warmer from east to west.
A flat upper-level trough, crossing the Iberian Peninsula from the WSW spreads northeastwards, yielding a favorable environment for scattered thunderstorms.Dynamic forcing for ascent in a moderately unstable and at most weakly capped airmass appears wholesome for repeated thunderstorm development in the highlighted area.Forcing will be diffuse to pinpoint but two windows for enhanced thunderstorm development exist, one between 06Z to about 18Z over Portugal and west / southwest Spain and a second one between 03Z onwards just offshore NW Portugal / NW Spain.
Forecast soundings hint on steep low-level lapse rates during the peak daytime heating over Portugal with robust LL instability release. As shear will stay weak no organized thunderstorm activity is anticipated but a few sub-severe hail reports are not out of the question.

We extended the thunderstorm area well towards the north as a warm and humid airmass spreads northwards.