Estofex: Level 2 voor België, Nederland Level 1

Bericht van: Stefan (Wezep) , 18-06-2021 23:40 

https://www.estofex.org/cgi-bin/polygon/showforecast.cgi?text=yes&fcstfile=2021062006_202106182114_2_stormforecast.xml

Storm Forecast
Valid: Sat 19 Jun 2021 06:00 to Sun 20 Jun 2021 06:00 UTC
Issued: Fri 18 Jun 2021 21:14
Forecaster: PUCIK

A level 2 was issued in a belt from E Spain to France, S Belgium, W Switzerland and SW Germany mainly for large to very large hail, damaging wind gusts and also tornadoes (highest risk over S France during the night).

A level 1 was issued across SE UK, Holland and NW Germany mainly for heavy rainfall, large hail and to the lesser degree for severe wind gusts.

SYNOPSIS

A deep trough covers W Iberia with a strong 40+ m/s jet-streak at its southeastern flank. In response to the strong southerly flow, trough is forecast to lift N-ward, being replaced by another low moving from the Atlantic E-ward. As the trough lifts N-ward, two short-waves are simulated along its eastern flank: one over Iberia and another one across W France. The exact timing and location of the troughs is different among the individual NWP models. Towards the N, a short-wave is also forecast to cross from Sweden into Finland. Towards the E, a ridge will has amplified from Central Russia into Poland with a low remaining over the Black Sea and Romania / Bulgaria.

Closer to the surface, a wavy frontal boundary will stretch from Scandinavia through the Northern Sea into France and Iberia. More significant overlap of abundant lower tropospheric moisture and mid-tropospheric lapse rates exceeding 6.5 K/km is anticipated across E Spain, W. Meditteranean, S to E France, Switzerland, Germany and the northern Black Sea.

... W France to BENELUX, UK and NW Germany...

While the kinematic environment will be less impressive here than to the S / SE, 0-6 km bulk shear should still be more than sufficient for well-organised storms, including supercells. Storms development will be likely tied to the passage of the short-wave trough that will start over the Bay of Biscay and move quickly towards the UK. Storm activity should start in the morning hours over SW France, spreading north during the day. Storms will be capable of (very) large hail and severe wind gust.

Cyclogenesis is forecast along the frontal wave ahead of the trough with backing low-level winds across N France. This will increase the amount of SRH and 0-1 km bulk shear and elevate the tornado threat by the evening hours. Currently, the exact location of SRH bullseye is not consistent among the NWP and thus it is not possible to pick up the region with the highest tornado threat.

Towards the night, strong WAA regime will support widespread storm initiation and one or two systems will cross S UK and BENELUX. As the boundary layer stabilizes and/or systems cross the frontal boundary, they will become elevated, reducing the severe wind gust threat to some degree. Nevertheless, isolated large hail and very heavy rainfall threat will still be present.



Estofex: Level 2 voor België, Nederland Level 1   ( 1521)
Stefan (Wezep) ( 2m) -- 18-06-2021 23:40
Re: Estofex: Level 2 voor België, Nederland Level 1   ( 393)
Riny (Kerkrade) ( 168m) -- 19-06-2021 00:52
Re: Estofex: Level 2 voor België, Nederland Level 1   ( 419)
Tomas (Dilsen-Stokkem) ( 35m) -- 19-06-2021 01:18