... N Bulgaria to Ukraine ...
Ahead of the wavy cold front, progressing in front of the decaying mid to upper level trough, low to moderate instability is forecast by numerous models. GFS is the most optimistic one, with most of other models simulating values between 500 and 1000 J/kg. South and extreme northern Romania seem to have the highest possibility of CAPE exceeding 1000 J/kg. Moderate to strong wind shear (15 to 25 m/s of DLS) is forecast, tied to the approaching shortwave/cut-off. Strongest shear should be confined to southern to central Romania, decreasing towards north. Towards the evening hours, over the lowlands close to the Black Sea, a 15 m/s 850 hPa flow is simulated by both GFS and ECMWF. Spotty areas of moderate SREH over 200 J/kg is also forecast. The strongest forcing across the area should come from the rapidly translating mid level cut-off low over Romania and then from the front itself.
A large Level 1 is introduced for this region with well organised convection possible especially over Romania. Strong multicells and supercells capable of large hail are forecast, later on probably transforming into one or more QLCS with threat of severe wind gusts. Towards the evening hours, thanks to the enhanced LLS, tornado is not ruled out either. A low-end level 2 is issued for the regions, where the highest coverage of severe is forecast. Threat of excessive precipitation will be mostly confined to the N Romania/ S Ukraine, where a warm, more stagnant part of the wavy frontal boundary is expected to be located.
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