19-07-2016 22:52 | Estofex | m.b.t. 20-07-2016 t/m 21-07-2016
Storm Forecast
Valid: Wed 20 Jul 2016 06:00 to Thu 21 Jul 2016 06:00 UTC
Issued: Tue 19 Jul 2016 22:52
Forecaster: PUCIK
A level 1 was issued for N England and Scotland mainly for excessive precipitation and to the lesser degree for large hail.
A level 1 was issued for N France, BENELUX and NW Germany mainly for large hail, severe wind gusts and excessive precipitation.
A level 1 was issued for parts of E Spain mainly for large hail and severe wind gusts.
A level 1 was issued for parts of Russia mainly for excessive precipitation and to the lesser degree for tornadoes and large hail.
SYNOPSIS
At mid to upper troposphere, a ridge will stretch from the Central Mediterranean towards Germany and S Scandinavia. To the west, a large cyclonic vortex resides over the Atlantic and its short-wave will cross Great Britain / NW France / BENELUX during the forecast period. A plume of steep lapse rates has already advected over much of the region and in combination with rather moist lower troposphere ahead and along cold front should contribute to development of latent instability. Another region with DMC activity will be over Russia, underneath a large, quasi-stationary closed low that is forecast to deepen during the forecast period. Both regions deserve a closer inspection regarding potential for severe weather.
DISCUSSION
... Central France, BENELUX, NW Germany ...
It is difficult to put all details together for the setup over this region as model solutions diverge to some degree. Moderate CAPE values (1000 - 2000 J/kg) are forecast towards 18 UTC as 2 m dewpoints reach upper teens and are ovespread by moderately steep mid tropospheric lapse rates (around 7 K/km between 800 and 600 hPa layer). DLS will reach 10 to 20 m/s, increasing southwards and towards the evening hours. Hodographs look quite messy or with veer-back-veer pattern, suggesting that environment is not very conducive to well developed, persistent supercells. Thus, expected storm type is a mixture of multicells, perhaps with one or two brief supercells. Storms will form especially in the evening to night hours as the decaying cold front approaches the area. Pre-frontal convergence zones could also aid in the initiation, but forecast soundings suggest pronounced cap early into the day. Large hail or severe wind gusts will be possible especially with the first storms (forming in higher LCLs and steeper lapse rates environment) while the later, overnight and likely elevated storms will primarily bear a heavy precip threat.
(alleen de voor NL en aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Hagel(-schade) | Onweer/blikseminslag | Verwachtingen/waarschuwingen | Wateroverlast/(zware) neerslag | Wind/storm (-schade)
