Storm Forecast
Valid: Wed 10 Apr 2013 06:00 to Thu 11 Apr 2013 06:00 UTC
Issued: Tue 09 Apr 2013 21:06
Forecaster: PUCIK

No threat levels have been issued.

SYNOPSIS

A pronounced cyclonic activity linked to a fresh zonal flow at mid and upper troposphere is forecast over much of Western Europe with a "Siberian high" stagnating over continental Russia and surrounding areas. Southeastern Europe should be under low geopotentials with cool mid-level temperatures with northwesterly winds increasing in speed towards the south. An ill-defined, gradual north-south temperature gradient without any significant frontal zones, apart from Western Europe - namely France, should dominate the situation.

DISCUSSION

... Germany ...

With moister polar maritime airmass over the region, NWP shows considerable shower activity in the diffluent mid-tropospheric flow. As winds increase in the mid-levels, most of the country should be under strong DLS, with values over 20 m/s. However, rising geopotential heights and mid-level temperatures preclude any chances for pronounced destabilisation and strong DMC activity posing severe weather threats.

... Balkans ...

On the verge of the strong northwesterly flow aloft, strong vertical temperature gradient will exist thanks to the cold mid-level temperatures. Some hundreds J/kg of CAPE should become available with the daytime heating. Wind shear should increase from northeast to southwest with DLS values between 15 and 20 m/s on the western fringe of unstable airmass. Nevertheless, shear below 4 km should be very weak, so considering rather low-topped convection, "effective" shear will likely stay rather weak. Nevertheless, steep lapse rates along with low freezing levels might result in some very isolated report of marginally severe hail, especially over E Slovenia, E Croatia and Serbia.