SYNOPSIS
West European trough moves northward as southern main vort-max/short-wave trough axis turns from Tunisia into west Mediterranean. This negatively tilted and quite intense short-wave trough will provide QG forcing due to strong DCVA over west/north-west Mediterranean during the period. Affected air mass is slightly unstable due to rather moist low levels and neutral to slightly unstable lapse rates. Further north and east, hot subtropical air mass originating from northern Tunisia is present in the range of a high from Adriatic to Germany. Steep mid-level lapse rates are indicated by latest soundings over this region. Quite cool air mass is present in the range of two long-wave troughs over western, and eastern Europe.
DISCUSSION
Benelux, north-western Germany, western and southern Germany region
Strong southerly to south-easterly jet moves across Germany, where subtropical air mass characterized by steep mid-level lapse rates remains. In the boundary layer, moisture is expected to increase and CAPE will likely reach up to 2000 J/kg. Initiation will be uncertain again given strong capping inversion over most places. Cap will weaken further west near the German/French border, where initiation is most likely in the range of a weak convergence line. Thunderstorms that form will likely develop into supercells capable of producing large or very large hail as well as severe wind gusts given dry mid-level air mass. Due to cold pool formation, thunderstorms may cluster while moving rapidly northward into Benelux and north-western Germany. Tornadoes are forecast especially from the Netherlands to north-western Germany and Rhine valley, where high low-level helicity will develop in the evening hours. Given strong low-level vertical wind shear of more than 12 m/s in the lowest kilometer, even strong tornadoes are not ruled out. To the east and southeast, strong capping inversion and large scale sinking may suppress deep convection. However, every storm that may develop has the potential to become severe quickly, and an update may be necessary.
West European trough moves northward as southern main vort-max/short-wave trough axis turns from Tunisia into west Mediterranean. This negatively tilted and quite intense short-wave trough will provide QG forcing due to strong DCVA over west/north-west Mediterranean during the period. Affected air mass is slightly unstable due to rather moist low levels and neutral to slightly unstable lapse rates. Further north and east, hot subtropical air mass originating from northern Tunisia is present in the range of a high from Adriatic to Germany. Steep mid-level lapse rates are indicated by latest soundings over this region. Quite cool air mass is present in the range of two long-wave troughs over western, and eastern Europe.
DISCUSSION
Benelux, north-western Germany, western and southern Germany region
Strong southerly to south-easterly jet moves across Germany, where subtropical air mass characterized by steep mid-level lapse rates remains. In the boundary layer, moisture is expected to increase and CAPE will likely reach up to 2000 J/kg. Initiation will be uncertain again given strong capping inversion over most places. Cap will weaken further west near the German/French border, where initiation is most likely in the range of a weak convergence line. Thunderstorms that form will likely develop into supercells capable of producing large or very large hail as well as severe wind gusts given dry mid-level air mass. Due to cold pool formation, thunderstorms may cluster while moving rapidly northward into Benelux and north-western Germany. Tornadoes are forecast especially from the Netherlands to north-western Germany and Rhine valley, where high low-level helicity will develop in the evening hours. Given strong low-level vertical wind shear of more than 12 m/s in the lowest kilometer, even strong tornadoes are not ruled out. To the east and southeast, strong capping inversion and large scale sinking may suppress deep convection. However, every storm that may develop has the potential to become severe quickly, and an update may be necessary.
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