Mesoscale Discussion
Valid: Sat 18 Jun 2016 15:00 to Sat 18 Jun 2016 19:00 UTC
Issued: Sat 18 Jun 2016 15:12
Forecaster: GROENEMEIJER

South and east Romania and north Bulgaria...

A very dangerous scenario is evolving, with a risk of intense tornadoes, giant hail, damaging downbursts and flash floods.

The MD area is characterized by very rich low level moisture, with dew point temperatures of 22-24 C measured. In combination with very steep lapse rates, extremely instability has built 3000 - 5000 J/kg MLCAPE should be available across this area, which is confirmed by the 12 UTC Bucharest sounding.

Deep-layer wind shear of around 25 m/s should be present. East of a convergence zone west of Bucharest, easterly surface winds should create considerable low-level shear and looping hodographs with e.g. the ECMWF model developing a local 200-400 m2/s2 maximum of storm-relatuive helicity.

Satellite imagery and radar shows a powerful supercell over the northern parts of the MD area. Visible atellite imagery shows towering and glaciating cumulus within the convergence zone where convective initiation is imminent. The extreme instability and more than adequate wind shear suggest that the existing supercell is very powerful and one or more powerful supercells will develop.

The supercells will be capable of producing strong tornadoes, with a violent tornado not excluded, giant hail (>10 cm), damaging downbursts and flash floods.