26-08-2023 17:06 | Estofex | m.b.t. 27-08-2023 t/m 28-08-2023
Storm Forecast
Valid: Sun 27 Aug 2023 06:00 to Mon 28 Aug 2023 06:00 UTC
Issued: Sat 26 Aug 2023 17:06
Forecaster: TUSCHY
A level 3 was issued for the Balearic Islands mainly for multiple rounds of all kind (extreme) severe events, including significant tornadoes, damaging winds and excessive rain.
A level 2 extends from SE Spain to the Alps with varying potential for significant severe. Corse/Sardegna with damaging winds/large hail turning more into an excessive rain/tornado threat over NW Italy.
A level 1 was issued for a belt from Czechia to Poland into the N-Ukraine mainly for excessive rain, wind and hail. An isolated tornado is possible mainly over CNTRL/NE Poland into SW Belarus.
A level 1 was issued for NW Germany and parts of the Netherlands mainly for an isolated tornado event (Germany) and heavy rain (the Netherlands).
A level 1 was issued for SW Turkey mainly for isolated large hail/severe wind gusts.
SYNOPSIS
An anomalous trough over W Europe becomes the main driver for this severe weather outbreak. The main energy drops south into a sharp upper trough configuration, which shifts its tilt from positive to negative during this forecast while crossing the W Mediterranean. Its 500 hPa geopotential height anomaly is rather impressive for this time of year. Even more impressive is the low/mid-tropospheric pressure response with a rapidly deepening low. ECMWF brings this depression to record level over the Ligurian Sea during the end of the forecast with similar results of GFS. This evolving depression pushes a cold front from the W to the CNTRL Mediterranean.
The northern part of this trough evolves into a lower amplitude wave, which crosses N Germany during this forecast period.
East of this trough configuration a wavy frontal bounday extends from the Italian depression NE towards Poland, where IFS-ENS agrees nicely in another evolving/weak depression.
Overall NWP guidance agrees well in this setup with ongoing manageable discrepancies regarding the speed of the Mediterranean cold front and geometry/placement/intensity of the LL depression over the Ligurian Sea. Those discrepancies affect mainly the nowcast and placement of potential most significant severe. Overall agreement in numerical guidance increases confidence in a widespread severe thunderstorm outbreak over parts of Europe.
DISCUSSION
... NW Germany and parts of the Netherlands ...
Placed in a moist environment with low T-Td spread, moderate CAPE up to 7 km AGL and top weighted shear profiles indicate a chance for scattered showers/thunderstorms in a weakly capped environment. Any more organized cell with deviant motion will have adequate SRH for some rotation and an isolated tornado threat/hail risk exists. Activity weakens after sunset.
Slow moving convection over the W-Netherlands poses a local heavy rainfall risk.
(alleen de voor NL en direct aangrenzende gebieden relevante tekstdelen zijn overgenomen, klik hier voor de volledige forecast, red.)
Verwachtingen/waarschuwingen | Wateroverlast/(zware) neerslag
