04-06-2016 18:39 | Estofex | m.b.t. 05-06-2016 t/m 06-06-2016
Storm Forecast
Valid: Sun 05 Jun 2016 06:00 to Mon 06 Jun 2016 06:00 UTC
Issued: Sat 04 Jun 2016 18:39
Forecaster: TUSCHY
A level 2 was issued for W-Germany, NE-France, S-Belgium and Luxembourg mainly for isolated large hail, severe wind gusts and heavy/excessive rain.
A level 1 surrounds the level 2 and covers most parts of SE and parts of CNTRL-/E-Europe mainly for isolated excessive rainfall amounts and isolated large hail/severe wind gusts.
SYNOPSIS
Omega block continues over CNTRL-/N-Europe. Deepening trough along its eastern fringe pushes an active cold front to the E/SE, which is one focal point for CI during the forecast period from S-Poland to far SW-Russia. The omega's ridge still features low/weak mid-level geopotential heights/height gradients with rather cool temperatures at 500 hPa. Hence, another day with widespread thunderstorm activity is anticipated. Active southern branch of the subtropical jet forces numerous mid-level waves over S-Italy to the east. Interaction with meager low-/mid-tropospheric moisture keeps thunderstorm probabilities on the low-end side.
DISCUSSION
... NE France, Belgium, Luxembourg and W-Germany ...
There's not much change regarding anticipated ingredients. Deep layer flow remains weak to non-existent ... despite 10-20 kt 1-8 km easterly flow over Luxembourg and Belgium. Decaying mid-level vortex induces a weak mark at the surface with divergent model signals regarding a closed BL circulation or a pronounced E-W aligned surface trough. Emitting dry/stable air from a 1025 (plus) hPa high over the N-Sea converges with cyclonic flow of the aforementioned surface feature and creates a diffuse E-W aligned convergence zone from NE France to W-Germany.
BL mixing ratios increase to 9-12 g/kg beneath modest mid-level lapse rates. Forecast soundings in this region show MLCAPE of 1.5 kJ/kg and locally higher MUCAPE peaks. Air mass is weakly capped and either orography or deep convergent flow induce scattered to widespread DMC activity. Given amount of CAPE build-up and marginally enhanced deep-layer flow, well organized and slow moving multicells are forecast with confined swaths of heavy/excessive rain. Large hail is possible during CI given a dry 4-6 km layer. Also, well mixed and dry low-tropospheric profiles in forecast soundings indicate a chance for both, isolated strong / severe downbursts and strong cold pools. The latter one would support a gradual upscale growth of DMC activity into numerous leisurely westward propagating smaller-scale thunderstorm clusters. Strong wind gusts along the leading edge and excessive rain will be the dominant risk.
Given expected high coverage of reports including the chance of a few very heavy rainfall events, a confined level 2 area was added.
Surrounding the level 2, pulsating convection with numerous more intense updrafts once again result in a few heavy/extreme rainfall events on a very localized scale.
(alleen de voor NL en aangrenzende gebieden relevante tekstdelen overgenomen, klik hier voor de volledige forecast, red.)
Hagel(-schade) | Onweer/blikseminslag | Wateroverlast/(zware) neerslag | Wind/storm (-schade)
