Mesoscale Discussion

Mesoscale Discussion
Valid: Tue 11 Jun 2019 13:00 to Tue 11 Jun 2019 15:00 UTC
Issued: Tue 11 Jun 2019 13:39
Forecaster: TUSCHY

The follwoing MD was issued for parts of far E-Germany, far W-Poland and the Czech Republic to update on latest information.

Remote-sensing data reveals mostly clear conditions over the area of interest with a broad/diffuse CU field aligned N-S over far W-Poland amidts a weak low-tropospheric flow regime. This CU field extends S into the CNTRL Czech-Republic, where low tropospheric speed convergence due to 15-20 kn SE-erly near BL flow over S-/CNTRL Czech Republic is analyzed. Finally temporal CU build-up occurs next to the Ore Mountains, where weak thermally direct circulations cause another region with broad/weak convergence.

12Z soundings from Praha and Wroclaw show a weakening cap in the 950-850 hPa layer with steep lapse rates atop. Praha also shows effective moisture pooling within this low-tropospheric confluence zone whereas Wroclaw remaining a bit more mixed at lower levels. Both soundings support model guidance with MLCAPE in excess of 2000 J/kg and effective DLS of 20-30 kn.
With T2m approaching 27-30C, convective initiation becomes possible in the following 2-3 hours. Weak cyclonic flow aloft and limited support by the LL confluent flow regime question coverage of storms with orographic support probably the best area to get numerous thunderstorms going.

CAPE/shear space is adequate for organized multicells/isolated supercells with large hail and severe wind gusts the dominant threat. In addition, moisture/CAPE content along the Ore mountains next to the approaching low-tropospheric 20-30 kn flow from the S/CNTRL Czech Republic increase odds for thunderstorms to remain quasi-stationary for some time along the mountains with locally extreme rainfall amounts before becoming mobile by cold pool dynamics and lifting N into E-Germany.

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