Storm Forecast
Valid: Sat 13 Jan 2007 06:00 to Sun 14 Jan 2007 06:00 UTC
Issued: Fri 12 Jan 2007 20:39
Forecaster: TUSCHY

SYNOPSIS

An intense, but rapidly weakening low pressure area over the northern Baltic Sea will continue its eastward movement and is forecast to stall somewhere east of Estonia.
A warm, but very dry airmass will be advected over parts of SW Europe with an impressive EML, overspreading the western Mediterranean.
An upper-level low over the extreme eastern Mediterranean will finally leave the area of responsibility during the latter part of my forecast period.
The main focus for dangerous weather conditions will be an intense disturbance, crossing the North Sea from the west towards the east.
A developing coupled jet configuration over UK during the 15-18Z time frame should support impressive UL-divergence values and hence an intense depression, crossing the North Sea and finally reaching Denmark at about 00Z.
Models indicate a developing gale area on its upstream side with gusts up to hurricane force. This dangerous wind field will cross extreme NE Germany, Denmark and Kattegat during a 00-06Z time-frame, reaching the extreme western Baltic Sea during the end of my forecast period.


DISCUSSION

...Crete...

A slowly eastward moving upper-level low pressure area will support a significant thermodynamic modification in the low-/mid levels compared to the past few days. SSTs are around 15-17°C and 700hPa temperatures will drop down to -10°C, so an area of rapidly steepening lapse rates will be the result at least during the 06-12Z time - frame. There are some negative ingredients, which could confine thunderstorm coverage:
A dry and stable continental airmass from the NW will reach Crete , but PBL modification will occur betimes so that this negative factor could be balanced.
Another negative factor regarding widespread storm initiation will be a constant warming trend in the low-/mid levels ( 12Z onwards ) due to the southward moving system.
But models like GFS indicate an area of 200-400 J/kg SBCAPE around Crete and scattered storms are forecast to develop.
Weak DLS but steep LL lapse rates will be present so that an enhanced waterspout threat can be expected, although threat should be confined to a 09Z-15Z time - frame, where best LL-instability release can be seen.

... Scotland and N-UK...

Thermodynamic parameters become conducive for a few thunderstorms to evolve in the wake of the eastward moving intense depression. The area was included into a level-1, because of an enhanced tornado and severe wind gust threat, given the favorable kinematic parameters.

...Extreme N Germany and Denmark...

Right now, there are no indications that conditions will become fine for storms to form along the eastward racing cold front.

The main concern for enhanced convective activity will arise in the postfrontal airmass, where negative LI values will be present. An eastward shifting mid-level thermal trough will support an area of steep lapse rates and isolated thunderstorms will affect the area of interest. Main concern will be a damaging wind gust threat due to the aforementioned , already impressive background flow.
An upgrade may become necessary later on, if models indicate a better environment for a more robust thunderstorm threat in later model runs.