Storm Forecast
Valid: Wed 01 Dec 2010 06:00 to Thu 02 Dec 2010 06:00 UTC
Issued: Tue 30 Nov 2010 22:14
Forecaster: PUCIK

SYNOPSIS

At midlevels, a large cyclonic vortex will be centered over the Strait of Gibraltar, moving slowly to the southeast. By Thursday morning, the center will be located over Northern France, filled with arctic airmass. The vortex will amplify towards southeast in a short-wave trough rotating towards northeast. Strong mid and upper level flow will be observed on the southern flank of the cyclonic vortex. In the exit region of a cyclonically curved jet, cyclogenesis is forecast over the Mediterranean. Surface low is expected to move northeast, along with associated frontal system. Another short-wave trough will be situated over Eastern Europe, moving eastwards along with a surface low. Surface high is forecast over Southern Scandinavia, later in the day spreading into Russia.

DISCUSSION

... Southwest Iberia, Western and Central Mediterranean ...

Low-end instability built-up is simulated by models with MLCAPE values generally forecast to reach values less than 500 J/kg. Instability should develop especially thanks to the advection of cold airmass at mid levels of troposphere, thus enhancing the lapse rates. Even though strong wind shear will be associated with at least the southern part of this instability belt, meager CAPE values along with no strong, concentrated lift should preclude development of strong, well organised deep-moist convection. Rather than that, banded, weakly electrified convection is anticipated.

... Western coasts of Greece ...

Undergoing WAA is expected to draw moist air from southwest with dewpoints well over 16°C. Due to the subsequent overlap with the advancing cooler airmass at midlevels, instability will likely build up over this area with CAPE values in the range of 500-1000 J/kg. Along with strong bulk wind-shear exceeding 20 m/s in the 0-6 km layer, conditions would be more favorable for strong, well organised thunderstorm than over other Mediterranean areas. However, in this case, high CIN values are simulated due to the very warm airmass at 850 and 700 hPa, hindering the storm initiation and on top of that, no strong forcing is forecast. With low expected storm coverage, no Level is issued at the moment, albeit an update might be necessary during the day.