Storm Forecast
Valid: Sat 01 Aug 2009 06:00 to Sun 02 Aug 2009 06:00 UTC
Issued: Fri 31 Jul 2009 21:28
Forecaster: GROENEMEIJER

A level 1 was issued for northeastern Spain and southern France, mainly for large hail and damaging winds.

SYNOPSIS

Saturday at 0600 UTC... a meridionally-oriented mid/upper trough west of Ireland and the Iberian peninsula, is moving eastward. A (partially) elevated mixed layer spreads northward across eastern Iberia and much of France, ahead of a cold front approaching from the west.

DISCUSSION

NE Spain...S France...

During Saturday, 500-1000 J/kg of CAPE are expected to develop over southern France, and locally over 1000 J/kg across parts of northeastern Spain. On approach of colder air from the west, a convergence zone is expected to develop over southwestern France and adjacent parts of Spain during the afternoon. During the late afternoon and evening, storm initiation is expected within this zone. About 25 m/s (0-6 km) deep-layer bulk shear should eb available, which suggests that despite the relatively low CAPE, a couple of rotating storms may develop. These will bring a threat of large hail and downbursts. The front-parallel mid/upper flow, and the rather weak CAPE suggests that thet storms will probably cluster rapidly during the evening and evolve into large partly convective areas of rain, with little associated severe threat.