CONVECTIVE FORECAST
VALID 06Z WED 06/08 - 06Z THU 07/08 2003
ISSUED: 05/08 21:44Z
FORECASTER: HAVEN

General thunderstorms are forecast across Iberian Peninsula, France, Italy, Slovenia, Alpine countries, parts of Germany and Benelux, Ireland, southern and central England

General thunderstorms are forecast across Baltic States and northwest Russia

SYNOPSIS

Broad upper ridge over western half of Europe and Upper Low just east of the Baltic States are both stationary. A weak shortwave over the western British Isles and Bay of Biscay moves slowly east through the ridge and is expected over Benelux and central-France early on Thursday.
At lower levels... rather dry air has been advected deep into central Europe at the southeast flank of the surface high which is fairly stationary over the NorthSea and southern-Scandinavia. A shallow trough over Ireland to southern-England to WestCentral-France is hardly moving. Near and west of this latter feature, higher moisture /dewpoints between 17 and 21C/ is available.

DISCUSSION

...South and central England...France...
In the vicinity of the surface trough thunderstorms are expected to develop, especially downstream of the eastward moving shortwave. Since shear profiles are rather weak over this area, no organized thunderstorms are expected.

Also a few isolated thunderstorms might form by orography induced circulations over Iberian Peninsula, France, Italy, Alpine regions, extreme southern Benelux and southern Germany.

...northwest Russia...
Near upper low the atmosphere should be favourable for diurnally enhanced thunderstorms. Near the periphery of this upper low...deep layer shear of around 35 kts will be sufficient for organized multicells, which could produce isolated marginal large hail and windgusts near severe limits. The low instability /CAPE of 500 J/kg or below/ and the expected convective mode will limit the overall threat to below a slight risk.

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