Storm Forecast
Valid: Fri 14 Dec 2007 06:00 to Sat 15 Dec 2007 06:00 UTC
Issued: Thu 13 Dec 2007 20:24
Forecaster: TUSCHY

SYNOPSIS

A very disturbed weather pattern is present over Europe.
We have to deal with an intense high pressure area over west / northwest Europe and a flat upper-level vortex, affecting most parts of eastern / central Europe. During the forecast period, an upper-level low pressure area ( characterized by a well defined cold core structure ) moves south/southwestward, crossing the western Ukraina during the morning hours and reaching the Adriatic Sea during the late night hours.


DISCUSSION

...The Adriatic Sea...

SSTs at or above 15°C and arriving very cold -10 to -12°C at 850hPa create an environment with impressive LL lapse rates, but the main inhibiting factor for thunderstorms will be the very dry airmass. The question is if the fetch of the Adriatic Sea is large enough to establish a well mixed boundary layer. Modified soundings and GFS data suggest a slight possibility along the western Adriatic Sea as EL maps hint on a good chance of deep convection. RH at 700hPa is quite high ( about 70% ) and numerous vort max cross the Adriatic Sea from the ENE during the forecast period, so we can't exclude a few SFLOC reports just offshore along the east coast of Italy and over the northern Ionian Sea. Confidence in anything more than sporadic is too low and hence we decided not to issue a general thunderstorm area.
Instability analysis gives no hint on anything significant enhanced ( e.g. in the 0-3km layer ) due to the dry airmass but we won't exclude an isolated waterspout report where stronger updrafts can develop.

A few more thunderstorms should develop south / southeast of Greece, but a combination of weak shear / instability preclude a more organized thunderstorm risk and hence no level area was issued.