Valid: Thu 01 Dec 2016 22:00 to Fri 02 Dec 2016 06:00 UTC
Issued: Thu 01 Dec 2016 19:23
Intense mid-level frontogenesis associated with a PV intrusion and 500 hPa winds up to 60 m/s is expected in north-westerly flow in the coming hours, moving from southern Sweden across the southern Baltic Sea, northwestern and central Poland into southern Poland. Stretching of low-level air masses will cause rapidly steepening lapse rates below the PV intrusion. Inflow of a moist maritime low-level air mass is underway ahead of a cold front situated over southern Sweden at 18 UTC. With dewpoints up to 7°C over eastern Germany and rather steep low-level lapse rates, latest Lindenberg sounding already indicates weak CAPE.
Increasing CAPE and colder equilibrium level temperatures are expected across Poland during the night hours. A narrow cold frontal rain band is forecast with some lightning activity. Given low-level convergence along the gust front and very strong flow, mesovortices capable of producing severe wind gusts and brief tornadoes are expected to verify a level 1. Limiting factor is weakening low-level moisture, however, current thinking is that the convective line will continue in the morning hours with also continuing severe weather threat.