31-05-2012 22:04 | Estofex | m.b.t. 31-05-2012 t/m 01-06-2012
Storm Forecast
Valid: Thu 31 May 2012 06:00 to Fri 01 Jun 2012 06:00 UTC
Issued: Wed 30 May 2012 22:04
Forecaster: GATZEN
A level 1 was issued for southern Portugal and surroundings mainly for large hail.
A level 1 was issued for south-eastern Germany, the Czech Republic, Austria, Hungary, Slovenia, Croatia, Serbia, Bosnia and Herzegovina, Montenegro, Greece, Bulgaria, and south-eastern Romania mainly for large hail and excessive precipitation.
A level 1 was issued for western and central Germany mainly for tornadoes.
SYNOPSIS
At the southern flank of a deepening Scandinavian trough, cool air masses spread into Europe from the north-west. A cold front will be situated from southern France across the Alps to the Black Sea at Thursday morning. Due to a short-wave trough travelling with the westerly flow, a frontal wave will develop during the day, associated with warm air advection from central Germany to the Balkan region. Relatively steep lapse rates can return northward while rich low-level moisture currently across France will spread eastward. In response to diurnal heating, CAPE will develop from eastern France to southern/central Germany in the warm sector of the frontal wave. To the south and east, moist and unstable air masses of the last days will remain across Italy and the Balkans. A trough will affect Turkey.
DISCUSSION
Central Germany to southern Benelux
As the frontal wave passes by, a tongue of rich low-level moisture will advect north-eastward into western Germany. Although lapse rates are weak, QG forcing ahead of an approaching mid-level jet streak may provide enough lift to enable CAPE. Latest GFS indeed indicates weak CAPE during the day. Given the strong forcing and weak CIN, showers and thunderstorms are expected. Most updrafts will be weak due to the weak CAPE. However, vertical wind shear will increase along the northern nose o the moist air mass due to the approaching jet streak, and deep-layer vertical wind shear may exceed 20 m/s in the late afternoon hours. Additionally, the 0-1 km bulk shear will be strong along the warm front (10 m/s) and favourable veering profiles are expected. Some storms may therefore evolve into supercells capable of producing tornadoes. The main thread seems to exist in the afternoon and evening hours, when the mid-level jet approaches and the overlap of vertical wind shear and CAPE will be greatest. However, the greatest uncertainty will be the cloud-coverage and rain leading to a cool boundary-layer and weak chanced for thunderstorms. Later observations will indicate if the scenario of storms will really come true.
(Alleen de voor NL een aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Verwachtingen/waarschuwingen
