Storm Forecast
Valid: Mon 01 Mar 2010 06:00 to Tue 02 Mar 2010 06:00 UTC
Issued: Sun 28 Feb 2010 18:17
Forecaster: TUSCHY

SYNOPSIS

No significant synoptic feature breathes down on devestating "Xynthia's" neck during the following 24 hours. A weak disturbance over the Bay of Biscay slides northeastward, but gets squeezed as ridging builds in from the SW, whereas CAA keeps going further north. Another intense vortex approaches Portugal from the west, but this system won't exert influence on Portugal or Spain during the forecast (in respect of thunderstorm development). Brisk WNW flow covers the central Mediterranean with embedded disturbances, so unsettled conditions are forecast. N/E-Europe remains cold/stable.

DISCUSSION

... West-central France ...

A weak upper wave has some impact on the weather over SW/central France, probably until sunset. A languid warm front enters the forecast area from the SW during the morning hours, before fading away. Postfrontal low-topped warm sector features some marginal PBL moisture beneath cold mid-levels as cold upper wave crosses the area from the west. An isolated thunderstorm probably evolves along the weak baroclinic zone and/or just in the postfrontal warm sector with maximized activity along the coast of the Bay of Biscay. Expectedly in warm front cases, enhanced SRH1 develops along the warm front, displaced from any instability. However, as front breaks apart, some directional shear/SBCAPE overlap is possible during the afternoon hours, as CAPE is already on a rapid decline. Despite the fact that there is a low-end threat for a short spin up (tornado), the main risk will be strong to isolated severe wind gusts, as 20m/s 850hPa jet covers the warm sector. Anticipated, conditional thunderstorm coverage precludes a level 1 for now. The activity decays rapidly during the evening hours.

A few thunderstorms are also forecast over the Adriatic Sea. DLS is augmented, but latest model data indicates a too marginal SBCAPE build-up for deep/persistent updrafts, which could benefit from the DLS. In case a stronger storm will be able to evolve offshore, strong wind gusts and marginal hail remain the main hazard.