Storm Forecast
Valid: Sat 16 Jul 2016 06:00 to Sun 17 Jul 2016 06:00 UTC
Issued: Sat 16 Jul 2016 00:00
Forecaster: TASZAREK

A level 1 was issued for a belt extending from W Bulgaria and FYROM through E Serbia, W Romania, Ukraine and W Russia mainly for large hail and severe wind gusts and in lesser extent for excessive precipitation.

A level 1 was issued for W Romania mainly for excessive precipitation.

SYNOPSIS and DISCUSSION

A broad Azores high with ridge stretching in the belt from British Isles/France up to Belarus/W Russia inhibits DMC activity on the most of this area. Jet stream extends from N Atlantic trough British Isles, S Scandinavia, up to NW Russia. Two lows with shortwave troughts moves along jet stream zone. First travels eastwardly trough British Isles, North Sea and Benelux while second moves nortwardly trough Finland and weakens. In both zones a marginal instability will develop and result in a small probability for thunderstorms. A large cut-off is placed over NW Balkans and Adriatic Sea. A main thunderstorm activity is confined to its eastern flank along quasi-stationary frontal boundary, and convergence zone in the warm sector with the tropical airmass. Within mixing ratios up to 11-12 g/kg, diurnal heating and locally enhanced lapse rates, a weak CAPE up to 600-800 J/kg will develop in N-CNTRL Balkan Peninsula and W Romania. Thanks to jet streak on the eastern flank of the cut-off, these areas will be under influence of 25-30 m/s DLS and a lift zone (PVA lobes). As a results, developing convective storms may evolve into supercells (especially given favourable vertical veering wind profile, SRH ~ 300-400 m2/s2) and multicell clusters with bowing segments (MLS ~ 15 m/s). Within these, a large hail and severe wind gusts will be likely. In W Romania where a convergence zones with particularly moist vertical profile will occur (PW ~ 35-40mm), an excessive precipitation with local flash flooding will be not ruled out. Thunderstorms with heavy precipitation will remain active in this area during nighttime hours. Second area where severe convective storms will be possible is confined to a narrow quasi-stationary convergence zone in a warm sector in Ukraine and parts of W Russia. Converging air will result in a jump of boundary layer's moisture to 13-14 g/kg (MIXR) and thus a CAPE up to 1500-2000 J/kg. Although environment will remain under moderately sheared environment (DLS ~ 15 m/s), a multicell and locally supercell thunderstorms will be capable of producing large hail and severe wind gusts.