Forecast Update
Valid: Sat 21 Jul 2007 16:00 to Sun 22 Jul 2007 06:00 UTC
Issued: Sat 21 Jul 2007 15:40
Forecaster: DAHL

SYNOPSIS

See conective forecast.

DISCUSSION

... SE Germany ... E Czech Republic ... S Poland ... Slovakia ...

Storms will likely continue to develop over Switzerland and SW Germany during the next few hours in rather weakly unstable but strongly sheared air mass. On their eastward track, they will encounter increasingly unstable air. Though deep shear is likely to decrease somewhat, it should remain sufficient for organized storms, with 15 to 20 m/s. Low-level easterly to northerly winds should further strengthen with the development of the SFC low, which will likely increase the SRH, which has already reached 220 J/kg in the Munich 12Z ascent (integrated over the lowest 3 km). Current thinking is that there will be little linear LL forcing so that storms may at least initially remain rather isolated. These storms will likely evolve into supercells with a threat for large hail and damaging wind gusts. Reason for the upgrade is that the evolution of the SFC low seems to be captured rather well by the GFS, lending credibility to the kinematic-parameter calculations. Isolated very large hail seems to be possible, necessitating a level 2.

Also, the level one region has been extended to the south over E Europe a bit, given stronger shear and CAPE than previously anticipated (ref. Poprad-Ganovce 12Z ascent).