Storm Forecast
Valid: Fri 02 Mar 2007 06:00 to Sat 03 Mar 2007 06:00 UTC
Issued: Thu 01 Mar 2007 22:21
Forecaster: TUSCHY

SYNOPSIS

A strong zonal flow will continue over parts of central Europe, while cool and stable conditions prevail for NE Europe.
A pretty warm and dry environment can be found over the Mediterranean.

DISCUSSION

....Croatia, Bosnia and Herzegovina and Hungary...

A strong upper-level jet will reach the area during the early morning hours and will rapidly shift towards the SE.
The pressure will start to fall over those areas and a broad low pressure channel will develop with an enhanced increase of some LL moisture from the N-Adriatic Sea towards the NE.
Models like GFS indicate low-end instability release and a few thunderstorms will be able to form.
Rapidly diminishing upper-level support ( weakening divergence signals ) and still pretty warm low / mid-levels will inhibit any significant instability release. However, DLS of 25-30m/s will support a few organized storms with an isolated large hail and mostly sub-severe wind gust threat.

... Belgium, the Netherlands, parts of Germany and Poland...

... Early morning - afternoon hours...

A pool of pretty cold mid-level air will cross NE Germany and Poland from the west during this time-frame.
Forecast soundings indicate pretty moist atmospheric conditions accompanied by steep mid-level lapse rates. Although instability will be on the lower-end side there will be the possibility for an isolated short-lived funnel / tornado due to enhanced LL shear.
In fact, SRH-1 will be enhanced so each storm with some deviant storm motion will be able to ingest enhanced helical inflow, given surface based storm development with attendant low LCL values.
Storm coverage will be too low for warranting any higher probabilities.

... 00Z -06Z...

A very intense upper-level jet will extend into W-CNTRL Europe and will place Belgium, the Netherlands and NW / W-Germany under the favorable left-exit region. As a consequence, significant pressure fall is forecast and a strong low pressure area will develop over those regions.
The main concern right now will be a very well developed dry slot, which will reach the aforementioned regions during this time frame from the west.
It will intersect a tongue of pretty high LL dewpoints over extreme E/NE France ( Td values of 9 -11°C ).
Slowly cooling 850hPa temperatures, high dewpoints and rapidly steepening mid-level lapse rates look favorable for a few thunderstorms to form.
Nocturnal radiation will be offset by strong WAA and an intense LLJ and an isolated surface based storm can't be ruled out. Shear would be very favorable for a local tornado / severe wind gust threat.
If this scenario will stabilize during the next few model runs an update / upgrade will become necessary for those regions.
Even without any thunder each convective segment would pose an enhanced severe wind gust threat, given nearly 30m/s at 850hPa.