23-05-2024 23:33 | Estofex | m.b.t. 24-05-2024 t/m 25-05-2024
Storm Forecast
Valid: Fri 24 May 2024 06:00 to Sat 25 May 2024 06:00 UTC
Issued: Thu 23 May 2024 23:33
Forecaster: PISTOTNIK
A level 1 and level 2 are issued for the Netherlands, central to E Germany mainly for excessive convective rainfall and to a lesser degree for tornadoes.
A level 1 and level 2 are issued for the Czech Republic and Austria mainly for excessive convective rain, large hail and to a lesser degree for severe convective wind gusts and tornadoes.
A level 1 and level 2 are issued for Poland, Slovakia, Hungary and W Romania mainly for excessive convective rain, large hail and to a lesser degree for severe convective wind gusts.
A level 1 and level 2 are issued for NE Spain, S France, N Italy, Slovenia, parts of Croatia, parts of Bosnia-Herzegovina and North Macedonia for large hail, excessive convective rain and severe convective wind gusts.
A level 1 is issued for N Finland and NW Russia for severe convective wind gusts, large hail and tornadoes.
A level 1 is issued for central Turkey mainly for excessive convective rain.
A level 1 is issued for E Turkey and Iran for excessive convective rain, large hail and severe convective wind gusts.
SYNOPSIS
A channel of low 500 hPa geopotential and surface pressure stretches from the British Isles across central Europe to Turkey, opposed by a blocking high between W Russia and the Norwegian Sea. The subtropic jet runs across the Mediterranean region, the polar jet across Iceland and N Scandinavia.
Most of Europe is covered by moist airmasses - rather cool in the range of the strongest cut-off low over the British Isles and France, rather warm elsewhere.
DISCUSSION
... central Europe between central France, BeNeLux, Germany, Poland, the Baltic States, Romania and the Alps ...
Despite rather poor lapse rates, the rich low-level moisture is "recycled" into low to moderate CAPE (up to 1000 J/kg, locally more along convergence zones and/or delayed vertical mixing) and allows another round of scattered to widespread, daytime-driven thunderstorms. Under mostly weak vertical wind shear, single cells, multicells and loosely organized clusters are the expected convective modes, and excessive rain is clearly the main hazard. The highest storm coverage is expected at the forward flank of a small cyclone over central Germany, where faint warm air advection and positive vorticity advection create synoptic lift that overlaps with moderate CAPE from Hungary into the Netherlands. This belt is therefore covered by a level 2. In contrast, clouds and rain as well as low-level stabilization quench thunderstorm activity at the cyclone's rear flank across the SW half of Germany.
Marginally large hail, copious amounts of small hail and localized severe wind gusts are secondary hazards, especially from Austria, the Czech Republic and central Poland east- and southward, where lapse rates are slightly steeper and capping is slightly stronger, allowing higher CAPE and therefore more discrete storms. The same applies to the eastern level 1 area across the W Ukraine, W Belarus and NE Poland, where a lack of synoptic lift in vicinity of the blocking anticyclone keeps thunderstorm coverage lower.
Low cloud bases and pronounced low-level convergence can also allow the spin-up of a few short-lived tornadoes, most notably at the nose of the warm air advection regimes across the Netherlands and NW Germany, where low-level wind profiles are best with 0-1 km shear around 10 m/s and pronounced low-level veering. A lack of insolation may be a limiting factor, though. Slightly enhanced tornado possibilities also stretch further along the most pronounced convergence zone across central Germany and Bohemia into E Austria.
(alleen de voor NL en aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Onweer/blikseminslag | Tornado/hoosverschijnsel(en) | Verwachtingen/waarschuwingen | Wateroverlast/(zware) neerslag
