CONVECTIVE FORECAST
VALID 06Z SUN 12/09 - 06Z MON 13/09 2004
ISSUED: 11/09 19:07Z
FORECASTER: DAHL

General thunderstorms are forecast across central Europe and the N Mediterranean.

General thunderstorms are forecast across E Spain.

SYNOPSIS

Intense upper trough expected over central Europe at the beginning of the FCST period ... is progged to lift northeastwards ... reaching the N Baltic States towards Monday morning. Weak mid/uppeer ridging will occur in its wake with several small perturbations imbedded. Farther downstream ... the next ... vigorous ... large-scale upper low should reach the British Isles late on Sunday.

DISCUSSION

...central Europe...
Weak instability will likely persist within weakening theta-e plume ahead of the lifting upper trough ... and given strong large-scale forcing for upward motion ... scattered TSTMS should form along the E edge of the theta-e tongue. A few of the storms may produce strong ... isolated severe ... wind gusts and maybe some hail given 20 to 25 m/s 0-6 km shear ... and 10+ knots 0-1 km shear. Meager thermodynamic fields should limit allover severe TSTM threat.

In the wake of the colt front over central Europe ... mesoscale regions of enhanced depth of convective mixing may occur ahead of small vort maxima ... however ... current thinking is that convection will be too shallow to be associated with either severe convective weather or lightning.

...E Spain ...
ELY low-level winds should continue to advect moisture into E Spain beneath steep mid-level lapse rates. This will likely result in ample instability ... and in a strong cap.

Present thinking is that the moist layer will decrease in depth farther inland ... where the it can be mixed out rather easily ... resulting in weakly unstable/weakly capped inverted-V type profiles ... maybe allowing for initiation primarily along mesoscale features like orography or outflow boundaries from Saturday's convection. Strong outflow winds ... maybe briefly approaching severe levels may occur with these storms. If storms manage to move into the stronger CAPE environment ... severe TSTM threat will be somewhat enhanced ... but relatively weak shear profiles should limit allower severe threat.

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