Mesoscale Discussion
Valid: Sun 01 Aug 2021 09:00 to Sun 01 Aug 2021 13:00 UTC
Issued: Sun 01 Aug 2021 09:04
Forecaster: GROENEMEIJER
A warm front was analyzed at 07 UTC stretching approximately from Udine to Maribor to Budapest to Kosice. The warm front is characterized by a zone of relatively high low-level humidity with surface dew point temperatures of 18-20 C. The front was reinforced by cold outflow of a weak MCS over Slovakia.
During the coming hours, the warm front should move northward a bit, while the environment south of the front is expected to warm quickly as a deep boundary layer develops. Although near-surface moisture will be diluted somewhat, abundant CAPE of 1000-2000 J/kg should nevertheless remain available. There, the near-surface wind will veer to southerly directions.
North of the front where the wind is generally easterly and the boundary layer will remain decoupled. A strongly sheared low-level flow with very long and looped low-level hodographs should evolve, resulting in 150-300 m2/s2 of storm-relative helicity in the 0-1 km layer across Slovakia by 12-15 UTC.
Storms are expected to develop first across Slovenia and the Eastern Alps and later farther east as well.
Any storms that track south of the front may include supercells as a result of the strong 25 m/s deep-layer shear, and produce very large hail and strong winds. The wind threat should gradually increase as the storms cluster and track eastward across Hungary. Gradually an eastward propagating line with damaging winds may evolve.
The storms that track near or to the north of the front across Southern Poland, Slovakia, and NW Hungary will be able to interact with the strong low-level flow resulting in strong low-level rotation and attendant tornado risk.
Until 13 UTC, a tornado risk may develop in particular within the inner indicated area, i.e., over far Northeast Austria, western and central Slovakia, and far northern and northwestern Hungary. In addition, these storms may produce large hail and isolated severe wind gusts.
