Storm Forecast
Valid: Sat 24 Feb 2007 06:00 to Sun 25 Feb 2007 06:00 UTC
Issued: Fri 23 Feb 2007 23:51
Forecaster: DAHL

SYNOPSIS

Upper vort max will cross E France and Benelux early in the period and lift NEWD across Germany during the day. Subsequent, quite intense vort max is expected to reach W France late in the period and will be focus for potentially severe evolution. Quasi-stationary large SFC low is centered over the northern Bitish Isles, exhibiting peripheral low-pressure centers ahead of the upper vort maxima. E Europe is covered by a large, cold SFC high.

DISCUSSION

... France ... Benelux ... W Germany ...

Weak instability is expected to develop ahead of the first vort max over France ... and scattered TSTMS should form in the late morning hours when large-scale forcing for ascent should increase. Deep shear is expected to remain on the order of 10 m/s, but 0-1 km shear of 10 m/s might be indicative of a slight threat for mesocyclones. An isolated marginally severe hail event along with strong wind gusts may occur, but should be too isolated to warrant a categorical risk. Low LCL heights, little capping and rather strong LLS may also support an isolated weak/brief tornado, but weak DLS should limit allover storm organization.

Substantial strengthening of the kinematic fields will occur over France upon approach of the next system late Saturday evening/night. Timing is rather poor to that coverage of SFC-based TSTMS may be limited. However, Strong forcing should allow at least scattered TSTMS to develop. Storms may be capable of severe wind gusts, hail and isolated tornadoes given 25 m/s DLS and 12 m/s LLS.

Otherwise ... severe threat should be quite low except for isolated waterspouts that may develop with the TSTMS over the Mediterranean.