CONVECTIVE FORECAST
VALID 06Z MON 24/11 - 06Z TUE 25/11 2003
ISSUED: 24/11 02:08Z
FORECASTER: GROENEMEIJER

General thunderstorms are forecast across The central and northwestern Mediterranean, southern and southwestern Iberia, northern Iberia and southwestern France as well as the extreme northwestern parts of the British Isles.

SYNOPSIS

An air-mass of polar origin is present near a complex mid/upper low/trough over southwestern Europe. Here, scattered thundery showers are ongoing and will likely continue, in particular over sea-water and near mesoscale areas of rising motion associated with shortwave troughs and upstream of mountain ranges.

Warm advection is forecast over and near the Thyrrenean Sea, southeastern France and western Italy. Especially over the southern Thyrrenean Sea and southward over Sicily some modest (elevated) latent instability may build.

A vigorous trough is expected to move eastward over Morrocco and affect the weather in the central Mediterranean after this forecast period as it lifts out of the Sahara. Some storms embedded in a mesoscale precipitation area will likely affect southern Iberia tomorrow. Some more isolated storms may later affect southwestern Iberia.

A stable air-mass is present over northern and eastern Europe so that thunderstorms are unlikely despite the strong dynamics in place near a developing cyclone over Finland.

A strong westerly flow is expected to move into extreme western Europe during the period. The polar air-mass that will be advected to the northern British Isles may allow for some thundery showers.

DISCUSSION

...Southeastern France, Thyrrenean Sea, Italy and the northwestern Balkans....
Ahead of a shortwave trough moving into the area, some probably elevated thunderstorms will be ongoing over southeastern France and northwestern Italy while some additional storms may develop further southward over the Thyrrenean Sea and Sicily. Convective activity will likely spread over central Italy and possibly affect the Adriatic Sea as well as the northwestern Balkans. The risk of any severe weather with these storms will be small because of the elevated nature of the storms and the small instability.

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