Forecast Update
Valid: Wed 18 Nov 2009 13:00 to Thu 19 Nov 2009 06:00 UTC
Issued: Wed 18 Nov 2009 13:41
Forecaster: PUCIK

A level 1 was issued for Denmark, NW Germany and Netherlands mainly for tornadoes

SYNOPSIS

Refer to the Storm Forecast.

DISCUSSION

... Denmark, NW Germany, Netherlands...

Satellite data shows a dry intrusion overspreading the main precipitation zone of the surface low with a strongly forced convective rainband seen on radar captures. This rainband is travelling on the back side of the large stratiform precipitation system, in proximity to the surface cold front. Even though models resolve only very little instability, it seems that vigorous forcing compensated for this factor. Even though no lightning is observed with this line, it may be well organised and pose a risk of severe threat. Very strong wind shear at lower levels ( over 15 m/s), SREH values exceeding 300 J/kg in 0-1 km layer and humid airmass present over the region are suggestive of a slight chance of tornado. Apart from tornadoes, severe wind gusts might occur, even though these are mostly linked to the intense pressure gradients of the low instead of the convective processes. Marginal Level 1 is introduced for the regions where a convective rainband is predicted to make a "landfall". The threat should decrease after it crossed Denmark, after 15 UTC.