CONVECTIVE FORECAST
VALID 06Z SUN 18/04 - 06Z MON 19/04 2004
ISSUED: 17/04 15:43Z
FORECASTER: DAHL

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

General thunderstorms are forecast across Ireland.

SYNOPSIS

Synoptically quiescent conditions prevailing over east-central and eastern Europe on Sunday ... with weak upper cut-off low lingering over Poland/Baltic States. Intense Atlantic upper trough is progged to continue digging SE while attaing a negative tilt ... spreading into the W Mediterranean by Monday 06Z. Relatively strong zonal upper frontal zone is stretching across the S-central and eastern Mediterranean Sea. At low levels ... large Atlantic low-pressure system will spread into weast and central Europe during the period. In its wake ... modified polar air mass will overspread much of W Europe ... with the main baroclinic zone extending from the North Sea across central Germany and N Italy into the SW Mediterranean Sea by Monday 06Z.

DISCUSSION

...Germany ... E France ... Switzerland...
It appears that rather shallow SFC-based layer of weak CAPE will persist ... and possibly increase somewhat in depth ... ahead of weak cold front especially over E France ... Switzerland and W/central Germany ...this front will merge with the Atlantic cold front late on Sunday. Vertical motion regime associated with the upper trough overspreading pre-frontal air mass ... along with diurnal heating ... will likely promote developemnt of scattered ... relatively shallow ... TSTMS over W Germany ... which may spread into central and S Germany until late Sunday evening.

...Ireland ...
Widespread cellular convection will likely persist in the deep polar air and spread into the E Atlantic and Ireland ... expect scattered TSTMS

...Iberia ...
Deep-layer shear is expected to be on the order of 30 to 40 m/s over the Iberian Peninsula ... but it looks that low-level CAA/subsidence will suppress deep convective mixing over this region. Ahead of the cold front ... narrow plume of subtropical/Atlantic air mass is FCST to be present ... which should bear little convective potential owing to weak lapse rates.

...Mediterranean...
Saturday's ascents across the central and W Mediterranean reveal nearly neutral profiles ... with little/no modification required to render air mass supportive to deep convection. Especially along the weak cold front ahead of southern-stream vort max moving across the W Mediterranean during the day ... TSTMS should be initiated. Given weak capping ... TSTMS may also develop downstream over Italy ... and possibly also over the W Balkan States. Especially along the cold front ... some potential for short-line segments/bow echoes exists given 20 m/s 500 hPa flow. Also ... low LCL heights may favor a few water spouts. However ... allover severe convective threat is considered too low for a SLGT ATTM.

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