19-06-2019 06:28 | Estofex | m.b.t. 19-06-2019 t/m 20-06-2019
Storm Forecast
Valid: Wed 19 Jun 2019 06:00 to Thu 20 Jun 2019 06:00 UTC
Issued: Wed 19 Jun 2019 06:28
Forecaster: PUCIK
A level 1 was issued for parts of France, W Germany, E Belgium, E Netherlands, Denmark and SW Sweden mainly for large hail, severe wind gusts and to the lesser extent excessive precipitation.
SYNOPSIS
Main macrosynoptic features are a large cyclonic vortex centered N of the British Isles and two ridges, one across the Central Mediterranean and the other over Ukraine and Belarus. In between of the ridges and the cyclonic vortex, a broad moderately strong SW-ly to W-ly flow has established over W and N parts of Europe. Two short-wave troughs are embedded in SW-ly flow, one will cross from France towards BENELUX during the day and the other will approach France by late evening hours. Another smaller scale low is currently residing over SW Turkey.
Closer to the surface, a frontal zone runs from NW Spain through France into the Northern Sea and Denmark. During the day, a cold front is forecast to cross France, BENELUX towards W Germany, while a warm front will lift NE-wards across S Sweden. Scattered to widespread DMC is forecast along the frontal boundary. Further DMC activity is expected in environment of weak flow, but abundant lower tropospheric moisture over parts of Central, Southeastern Europe and Turkey.
DISCUSSION
... France towards S Sweden ...
As of 06 UTC, elevated thunderstorms have formed over Belgium, N France and the English Channel on the edge of the advancing EML that was well sampled by 00 UTC Trappes sounding. At the same time, a large shield of clouds, remnant from the overnight convection over S France, is advected from France further NE-wards. It is possible that the elevated thunderstorms, as well as the cloud shield will affect surface heating in the following hours across BENELUX. Surface observations reveal dewpoints mostly between 12 to 16 deg C over the area, which is consistent with the latest model output.
By the afternoon, it is forecast that 1000 to 2000 J/kg of MLCAPE will develop over much of the region thanks to the steep lapse rates exceeding 7 K/km. DLS will be mostly between 10 and 15 m/s, favouring multicellular type of convection. Towards the evening, DLS will increase and transient supercells may occur, particularly over Denmark, where curved hodographs with around 150 m2/s2 of SRH in the 0-3 km layer are simulated. Current thinking is that scattered DMC will develop along the front and over Massif Central and move NE-wards. Towards the evening and night, an MCS may form over BENELUX, NW Germany and/or Denmark, as storms cluster together and move towards S Sweden.
Forecast soundings reveal steep lapse rates and high LCLs with well mixed and deep boundary layer, so that severe wind gusts may accompany stronger storms, particularly if an MCS will form in late afternoon or evening hours. Abundant CAPE in the hail growth zone will also allow for large hail and this threat will be most pronounced with transient supercells. Excessive rainfall may accompany the storms in the late evening or night, as LCLs decrease and storms cluster in bigger systems.
(alleen de voor NL een aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Verwachtingen/waarschuwingen
