Storm Forecast
Valid: Wed 29 Apr 2020 06:00 to Thu 30 Apr 2020 06:00 UTC
Issued: Tue 28 Apr 2020 21:32
Forecaster: PUCIK

A level 1 was issued across W Balkans mainly for large hail and to the lesser degree for heavy rainfall.


SYNOPSIS and DISCUSSION

At mid to upper troposphere, westerly flow dominates over much of Europe, disturbed in a series of short-wave troughs and weak ridges. On Wednesday morning, a trough is simulated over Switzerland, W Germany and NW Italy. It is forecast to move eastwards, filling with time. A belt of stronger flow will exist in between of the trough and a flat ridge over the S Mediterranean. Towards N, a more pronounced short-wave will rapidly move across N Russia. In the late afternoon to evening hours, a sharp short wave will approach UK and W France with pronounced synoptic-scale lift in the exit region of the jet.

While strong wind field with high SRH is forecast ahead of the aforementioned trough, lack of steeper mid-tropopsheric lapse rates should preclude risk of deep convection ahead of the advancing cold front. Scattered storms are expected behind the front, as lapse rates steepen with falling mid-tropospheric temperatures.

Higher coverage of storms is forecast across parts of Central and SE Europe, ahead and along the surface cold front and around the mountain chains in the area. Forecast soundings show skinny CAPE combined with rather weak flow throughout the troposphere, so that mostly disorganised and non-severe storms are forecast over most of the domain. While moisture content in the lower troposphere is still quite low, weak storm motion may result in a very isolated spots of excessive rainfall should storms concentrate in some locations.

Stronger shear is forecast over western Balkans as the mid-tropospheric flow increases from N to S. Here, 0-6 km bulk shear around 15 m/s may promote better organised storms that may be capable of isolated large hail. Lvl 1 is introduced for this region.