Forecast Update
Valid: Mon 22 May 2006 07:00 to Tue 23 May 2006 06:00 UTC
Issued: Mon 22 May 2006 07:19
Forecaster: GROENEMEIJER

SYNOPSIS

Refer to convective forecast...

DISCUSSION

Have upgraded NW Germany and eastern Netherlands to level 2. Strong large supercells are moving NEward over Niedersachsen in a highly helical environment with 35 m/s 0-6 km bulk shear. locally and acquire more surface-based character with threat of tornadoes, large hail and very strong gusts. Likely tornado damage has been reported over the western Netherlands last night.

Although the current storms are decaying as they become embedded in a larger stratiform area, more storms are likely form over the Netherlands, Niedersachsen and NRW. Solar heating will warm the boundary layer as clearing skies move in from the west. Favourable shear is expected to persist in these areas at least into the afternoon hours and additional supercells are anticipated.

Storms may move well into Denmark and southwestern Sweden later today and the situation will be monitored for an upgrade in those areas later today.

In response to diurnal heating, additional storms are likely to form over the northern Rhone Valley/Jura/Alsace to move northeastward. Shear profiles will likely be a little less strong here, but 0-6 bulk shear of around 25 m/s is still considerable. These storms will have large hail and strong/ severe gusts as the primary threats. If their coverage becomes large, an upgrade fro this area may be required, too.