Storm Forecast
Valid: Sat 02 May 2015 06:00 to Sun 03 May 2015 06:00 UTC
Issued: Sat 02 May 2015 05:57
Forecaster: GATZEN

SYNOPSIS / DISCUSSION

The polar jet remains on a rather southern position and extends from the Bay of Biscay to the Aegean Sea during the period. Embedded in the jet, a short-wave trough travels from the Adriatic Sea to central Turkey until Sunday. In its wake, ridging affects western Europe today. Late in the period, an Atlantic trough spreads into western Europe. At lower levels, a frontal boundary extends from The Channel to southern Germany, southern Poland, to north-west Russia and eastern Finland. Dry polar air has spread into Central Europe in the wake of this front, whereas wetter moisture is located to its south. However, weak lapse rates over most of Europe limit the development of CAPE.

Best chances exist across the northern Balkans, where better lapse rates are expected in the range of the eastward moving trough center. Diurnal heating is limited due to many clouds, but upstream clearing across northern Italy is expected to affect the Balkans during the noon hours. DCVA is forecast near the trough axis, and showers and thunderstorms are forecast in the noon and afternoon. Given 0-3 km vertical wind shear around 10 m/s, multicells are forecast, capable of producing locally large hail.

Embedded in the European long-wave trough, an intense vort-max travels northward across the Baltic region. A strong mid-level jet streak affects north-western Russia today. Ahead of a cold front, latest observations and Moskva sounding indicate a moist warm air mass spreading north. DCVA and WAA are expected to increase the lapse rate within the warm air mass. Weak CAPE may develop, although the broad cloud coverage limits diurnal heating. Showers and thunderstorms are not ruled out ahead of the cold front in the noon and afternoon. Favourably veering profiles and strong low-level vertical wind shear exceeding 10 m/s in the lowest kilometre can allow for storm organization, and mesocyclones are not ruled out, capable of producing tornadoes. The threat is marginal, given the weak instability, and a threat level is not issued.