Mesoscale Discussion
Valid: Wed 03 Jul 2019 13:00 to Wed 03 Jul 2019 17:00 UTC
Issued: Wed 03 Jul 2019 13:45
Forecaster: GROENEMEIJER

Scattered convective storms are ongoing across the southern Carpathian mountains, but have not moved into the lower Danube Plains, where a very unstable air-mass is present with 2000-3000 J/kg of mixed-layer CAPE and very steep mid-level lapse-rates of almost 10 K/km between 750 and 500 mb per the 12 UTC Bucharest sounding.

The sounding also shows that the temperature in the capping layer has decreased substantially since 00 UTC. Therefore, continued heating is expected to result in convective initiation across the Danube Plains during the coming hours, which is supported by NWP guidance.

Given the strong instability and about 15 m/s of bulk wind shear in the 0-3 km layer, transient supercells and well-organized multicells are expected with a risk of very large hail possibly well in excess of 5 cm. In addition, damaging downbursts and flash floods will be possible.

South of the Danube, across Bulgaria, the risk of well-organized storms will be a bit lower because of weaker wind shear, but ample CAPE implies an important risk of severe storms will nevertheless exist there as well.