Storm Forecast
Valid: Tue 31 Jul 2007 06:00 to Wed 01 Aug 2007 06:00 UTC
Issued: Tue 31 Jul 2007 09:52
Forecaster: VAN DER VELDE
SYNOPSIS
High pressure builds over western and central Europe between lows over Finland and Turkey, and a cut-off low arrives from the Atlantic Ocean to the Iberian peninsula. Cool air has spread over much of Europe, with the warm air from near the Scandinavian/Baltic low to east of the cold front over Russia, into southern Balkan where the cold front is stationary, Turkey, Mediterranean Sea and Spain.
DISCUSSION
...Sweden, Baltic states...
Some chance of land- and waterspouts exists, especially where the wind is weakest and convergence and low-level instability strongest.
...Russia, Ukraine...
Along the cold front, an axis of instability is indicated by GFS to be in good deep layer shear and SREH conditions... however, from theta-e at 700 hPa it can be seen the frontal plane is under a slope such that where convection is indicated (west of the surface cold front) it will likely be elevated and not profiting from the good shear. If convection develops too much to the east, it does not have as good shear available. It seems that early-on, around 12Z, MLCAPE is highest and surface-based convection possible within the good shear zone near the Ukrainian-Russian border and with 200-400 m2/s2 SREH 0-3 km and 15 m/s deeplayer shear storms may develop into supercells, with a threat of large hail and severe gusts. It is likely that an elevated MCS will develop and move northward along the front over Russia during the evening and night.
...Balkan...
Upper trough with lift and moderate/strong shear arrives during the evening over the level 1 area. Isolated to scattered convection may occur during the afternoon in the weakly capped area when shear is displaced to the northwest mostly out of the CAPE region. Towards 21Z, GFS predicts strong precipitation over northern Greece and western Bulgaria, when slightly enhanced shear (15 m/s 0-6 km, 100-200 m2/s2 SREH 0-3 km) is also present. A small chance of hail and gusts exists, but precipitation amounts and lightning seem comparatively more noteworthy.
