CONVECTIVE FORECAST - UPDATE
VALID 17Z SAT 07/02 - 06Z SUN 08/02 2004
ISSUED: 07/02 16:38Z
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across the southeast UK ... extreme north France and the BeNeLux States.

General thunderstorms are forecast across the UK ... W France ... beNeLux and W Germany.

SYNOPSIS

See convective forecast from 6 February 2004 20:12 UTC.

DISCUSSION

...UK ... NW France ... BeNeLux ... W Germany ...
Vigorous vort max is forecast to sweep across the UK ... North Sea ... BeNeLux ... E France and W Germany during the night. Increasing vertical motion ahead of this feature currently appears reflected by increasing depth of cellular convection ATTM over the N British Isles and the North Sea. Current thinking is that this activity will continue to intensify over the next hours ... and formation of a small mainly linear MCS is anticipated. Model data suggest that strongest low/mid-level flow will be just upstream of the maximum QG UVV's ... and 850 hPa flow is expected to be on the oder of 40 to 50 knots in the environment of the system ... possibly increasing to about 60 knots towards the SW over the SE United Kingdom. Meso- and convective-scale dynamics may well enhance the low to mid-level flow ... and downward momentum transport may support straight-line winds well in excess of 50 knots. Also ... modification of the shear profiles over land (increasing friction over coastal regions and orographic modification farther inland) may support a few rotating updrafts ... posing the threat of producing marginally severe hail ... and a brief tornado or two. Only negative is the cool nocturnal SFC temperatures over the land ... and convective threat may decrease some as the system moves inland. However ... especially over the coastal regions ... severe TSTM threat appears to be sufficiently high to warrant a SLGT.

...Central Europe ...
Scattered showers and isolated TSTMS have formed over large parts of central Europe in the deep polar air mass ... however ... with diurnal SFC cooling ... TSTM threat will likely diminish over the next few hours with this activity.

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