STORM FORECAST
VALID Sun 26 Mar 06:00 - Mon 27 Mar 06:00 2006 (UTC)
ISSUED: 25 Mar 19:20 (UTC)
FORECASTER: DAHL

SYNOPSIS

Longwave upper trough over the E Atlantic will make slow eastward progress ... with lead vort max expected to overspread extreme W Europe late in the period. Midlevel ridging downstream will spread into central Europe and the central Mediterranean. Vort max at the E flank of the ridge is expected to cross the Ionian region late on Sunday. Broad warm-advection regime ... affecting all of western and central Europe ... will persist E of the Atlantic trough.

DISCUSSION

...France and W Germany...
This time models show some clearer signals for evolution of deep instability over France towards late Sunday afternoon/evening ... which will spread into W Germany late in the period per latest GFS and NMM runs. Primary forcing for ascent should be due to WAA which is expected to exist over France and W Germany on Sunday evening. This ... and the late development of CAPE suggests that storms may tend to be elevated. Given minimal CAPE ... and probably reduced shear in the cloud-bearing layer ... severe threat doe not seem to be substantial despite rather strong 0-6 km bulk-shear magnitudes. Any storm that does tap BL air will have increased chances of becoming severe ... but allover threat should be too low for a categorical risk ATTM. An isolated TSTM or two may also occur over Germany in the afternoon hours where shallow CAPE should persist. Coverage should be too low for a TSTM area over this region however.

...Ionian Sea...
Shallow convection may develop over the Ionian Sea in response to approaching upper vort max early in the period. Current thinking is that unstable layer will be too shalow for widespread TSTMS ... and a TSTM area does not seem to be necessary ATTM.

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