Storm Forecast
Valid: Wed 16 May 2007 06:00 to Thu 17 May 2007 06:00 UTC
Issued: Wed 16 May 2007 08:23
Forecaster: GATZEN

SYNOPSIS

SYNOPSIS

Axis of amplified trough is located from western Scandinavia to northern Italy on WED. Upper highs are present to the west over north-eastern Atlantic and to the east over eastern Europe. Upper trough over Europe propagates slowly eastward during the period. At lower levels, a frontal boundary stretches from western central Russia to eastern Belarus, western Ukraine, and southern Balkans. This frontal boundary is expected to move eastward during the day. To the west, cold air mass is present over central Europe.

DISCUSSION

Western Russia, eastern Belarus, western Ukraine, Romania, Serbia, and eastern Adriatic

Along the frontal boundary, another round of convective activity is likely during the day. Latest 33658 Chernivtsi sounding indicates a well-developed EML over western Ukraine that will likely spread into eastern Belarus ahead of the cold front. Although low-level moisture is relatively weak, diurnal heating is expected to lead to CAPE in the order of 500 to 800 J/kg as forecast by GFS. Outflow boundaries of overnight's convection will be focus of initiation around noon. QG forcing at the anticyclonic entrance of upper jet will likely support developing convection during the afternoon hours. Although deep-layer wind shear will decrease during the day, 30 m/s southerly winds at the 300 hPa level will be available and storms are expected to organize. Given steep mid-level lapse rates, rather strong cold pools are forecast. Given weak low-level vertical wind shear, it is expected that cold pools will spread north-eastward, and clusters of thunderstorms also moving north-eastward may form during the afternoon/evening. Severe wind gusts will be the main threat, while supercells with large hail may form locally. Given numerous outflow-boundaries and heterogeneous wind/moisture distribution, a brief tornado is not ruled out. Limiting factors are mostly dry low-level air mass and weak vertical wind shear. Best potential seems to exist over eastern Belarus in the range of the warmest air mass, while threat will be significant weaker over western Russia, where instability is rather low, as well as over eastern Adriatic, where vertical wind shear is rather weak.