Storm Forecast
Valid: Tue 29 Apr 2025 06:00 to Wed 30 Apr 2025 06:00 UTC
Issued: Mon 28 Apr 2025 19:57
Forecaster: TUSCHY

SYNOPSIS

A blocking anticyclone is centered over CNTRL Europe. It gets framed by two distinct cut-offs, one W of Portugal and another one over the far E Mediterranean. The one W of Portugal features percentile ranks of MSLP/500 hPa heights below 10%. This indicates a rather strong system for this time of year. Phase diagrams show a gradual change towards a shallow warm core system although only modified moisture approaches the center and hence any subtropical development seems unlikely for now.
This feature becomes the main player for a potential multi-day severe weather event for parts of Spain/Portugal during this week. For this forecast period however CAPE/shear space remains displaced with rather low chances for anything organized for all of S-Europe.

DISCUSSION

... Lightning areas ...

A region of enhanced BL moisture with dewpoints around 10C overlaps with a westward fanning alpine EML plume. Resulting MUCAPE soars into the 800-1200 J/kg range while DLS resides in the 2-5 m/s region. Resulting thunderstorms evolve beyond noon along the orography, before drifting W. Initiating convection my bring some hail and strong downbursts with isolated heavy rain. Overall severe risk does not justify an upgrade although spotty level 1 conditions can occur. Thunderstorms decay beyond sunset.

Over parts of Italy and Turkey, a similar CAPE/shear space causes scattered thunderstorms with isolated severe but no level 1 upgrade was performed due to the overall rather limited coverage. Crete could see isolated heavy rain with persistent upslope flow.

Over Portugal and SW Spain, a few elevated nocturnal thunderstorms occur embedded in a more stratiform rain event with spotty heavy rain.