Storm Forecast
Valid: Wed 12 Oct 2011 06:00 to Thu 13 Oct 2011 06:00 UTC
Issued: Tue 11 Oct 2011 21:27
Forecaster: PUCIK

A level 1 was issued for coastal areas of the central part of the Black Sea mainly for excessive precipitation.

SYNOPSIS

At midlevels of troposphere, a ridge is expected to amplify over parts of Western Europe and Eastern Atlantic towards north, inducing prevailing northwesterly flow over much of Europe. More towards east, a deep trough resides over much of Northern, Central and Eastern Europe, reaching all the way down to Turkey. Embedded in it, a short-wave trough will rapidly progress over Eastern Central and Eastern Europe, placed in the left-exit region of northwesterly jet-streak. Short-wave is associated with the frontal system (namely cold front), which will cross the region with significant CAA behind it. Frontal system on the western part of the system should stagnate over Central Germany, with frontal zone stretched in NW-SE direction. Regarding surface pressure fields, situation looks similar regarding the pattern with building high over Western part of forecast domain and low pressure over east.

Most of the Europe should be under relatively stable and dry airmass, preventing DMC formation. The highest chances of thunder seem to be over SE Europe, owing to the presence of cool mid-level temperatures over the warm SST. However even here, coverage should decrease during the day as the mid level trough moves eastwards.

DISCUSSION

... Eastern Poland, Belarus, W Ukraine...

Favorable position of the cold front regarding to the presence of mid and upper level forcing (sharp trough and exit region of a mid and upper tropospheric jet-streak) gives some hints of the possibility of strongly forced convection in the moist neutral profiles that are observed over the region per sounding analysis. The downside are weakening vertical wind profiles in the lower levels of troposphere, as suggested by NWP output. With winds reaching only around 15 m/s at 850 hPa, moist profiles and marginal instability, threat of wind gusts seems to be very low to warrant a Level at the moment. Still, region deserves some more attention during the day for hints of stronger winds and higher chance of severe gusts.

... Coastline areas of the central Black Sea ...

With the NWP revealing favorable synoptic scale forcing for the region, low to moderate degree of latent instability is likely, with MLCAPE values generally around 500 J/kg. As the impulse moves towards northeast along with the trough, so will the focus for the storm initiation. It is likely that the highest coverage of storms in the highlighted region will be in the first 6 h of the forecast period, gradually dimnishing thereafter. Rather moist profiles with high values of PW and parallel flow to the low-level boundary, chances of highly efficient rain producing and backbuilding MCS will exist over the region, with potential for producing excessive precipitation.