Extended Forecast
Valid: Thu 28 Feb 2008 06:00 to Fri 29 Feb 2008 06:00 UTC
Issued: Tue 26 Feb 2008 23:42
Forecaster: TUSCHY
SYNOPSIS
Geopotential height maps still have a quite messy look with numerous more or less active troughs scattered over Europe. As most of them are not connected to convective activity only one of them will be of main interest. This feature crosses Spain from the WNW, entering the western Mediterranean during the late afternoon hours.
South of Iceland a rapidly eastward racing 105m/s streak at 300hPa points to a change of the European weather pattern during the next few days but this has not yet any influence on the current forecast period.
DISCUSSION
....Spain....
Upper-level trough, marked by a notable cool down of the mid - levels gradually spreads southeastwards, crossing Spain during the daytime hours and affecting the western Mediterranean later on.
Only modest boundary layer moisture but rapidly steepening mid-level lapse rates favor a broad area with deep convection in a weakly sheared environment. All indications hint on the best instability release over SE Spain during the afternoon hours with up to 600 J/kg nearly uncapped SBCAPE possible. This area also has the best chance for stronger pulsating storms with an attendant marginal hail risk. LL CAPE is somewhat enhanced but right now environment in the lowest 3km is not that impressive to include a funnel risk.
...Extreme eastern France and west-central Germany....
A strong low pressure system enters the area of interest during the evening hours from the west. Ahead of this feature good moisture advection is underway while lapse rates at mid-levels steepen to about 6K/km. At the moment forecast soundings indicate a borderline case for deeper convection between 00Z and 06Z with slightly negative LIs, a very low LCL and strong shear at the lowest level. For now we will ensue the model pool, reflecting only a marginal chance for convection as we also want to wait for the next model runs.
...Parts of the Aegean Sea....
A few thunderstorms could evolve over the northern Aegean Sea but no organized thunderstorm risk is expected.
