CONVECTIVE FORECAST
VALID 06Z TUE 18/11 - 06Z WED 19/11 2003
ISSUED: 17/11 18:37Z
FORECASTER: HAKLANDER

General thunderstorms are forecast across parts of NW Europe.

General thunderstorms are forecast across the Western Mediterranean.

SYNOPSIS

Slightly meandering jetstream across the Eastern Atlantic runs across Northern Scotland and Southern Scandinavia towards the Black Sea. Along the baroclinic zone, our attention is focused on a disturbance in the LER of an embedded jetstreak of 130+ knots. A closed ULL across NW Algeria remains quasi-stationary thoughout the forecast period.

DISCUSSION

...North Sea...
According to AFWA MM5/12Z, a small baroclinic disturbance at low levels over Northern Scotland at TUE/06Z, should rapidly move eastward across the North Sea and the Oslo area and is forecast across the Baltic States by WED/06Z. Low CAPE in the polar air mass behind this system could cause a few storms to become thundery. Winds at 925 hPa are forecast to reach 70 knots just south of the system's core, and will likely exceed 50 knots in the polar air mass behind it as well. Because of the forecast latent instability across the GEN TSTMS area, downward momentum transport in convective downdrafts could produce severe windgusts of 50+ knots at the surface. In the warm sector of the baroclinic disturbance, non-convective windgusts of 50+ knots could also occur.

...Western Mediterranean...
Although about 500 J/kg MUCAPE is forecast across central parts of the Mediterranean, thunderstorms are not expected to form there due to CIN near a high pressure ridge. Farther west, closer to the ULL, there is only little CIN left. Synoptic scale upward motion, along with the presence of a deeper moist layer, should enable the formation of some scattered thunderstorms. With only low CAPE and low deep layer shear of 30 knots or less, severe thunderstorms are not considered likely.

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