Storm Forecast
Valid: Thu 06 Apr 2017 06:00 to Fri 07 Apr 2017 06:00 UTC
Issued: Wed 05 Apr 2017 21:00
Forecaster: GATZEN

SYNOPSIS / DISCUSSION

Low geopotential is present downstream of NE-Atlantic ridge. Two intense vort-maxima are located across the west Mediterranean and over central Europe, the latter digging south-east reaching Romania late in the period.

Downstream of these active short-wave troughs, broad low geopotential and relatively weak mid-level flow affects the Mediterranean, south-eastern, and eastern Europe. Diurnal heating of the pretty cold air mass has caused steep lapse rates over eastern Europe overlapping with quite rich low-level moisture. On Thursday, a cold front moves from central Europe south-east. Ahead of this cold front, thunderstorms are expected to form. Additional storms can form near the trough centres.

Given the weak vertical wind shear over most places, storm organization is expected to be weak. Pulse storms can produce excessive rain and hail locally. Better storm organization cannot be ruled out from east Belarus to western Russia. While the central European trough passes to the south-west, surface front becomes stationary. With south-easterly flow, warm air advection evolves during the day, creating an overlap of the frontal moisture with steeper lapse rates. Vertical wind shear will be about 15 m/s in the lowest 3 km. Main limiting factor is the low-level heating that might be too weak to allow for surface-based convective storms. However, if low-level buoyancy evolves, multicells and brief supercells are not ruled out, capable of producing large hail and maybe a tornado. Overall threat is weak and given the weak confidence in surface heating, a level 1 was not issued.