Forecast Update
Valid: Sun 07 Sep 2008 14:00 to Mon 08 Sep 2008 06:00 UTC
Issued: Sun 07 Sep 2008 14:08
Forecaster: DAHL

SYNOPSIS

Refer to convective forecast from 6 September 2008.

DISCUSSION

... Italy ...

Some of the 12Z ascents from Italy show stronger thermodynamic support than had previously been anticipated, along with quite ample shear. Storms will likely become supercellular, capable of producing isolated very large hail and destructive outflow winds. Coverage seems to be maximized over NE Italy towards S Austria and Slovenia, where a level 2 threat has been introduced. Low-level thermodynamic and kinematic fields apparently vary rather strongly based on the latest radiosonde data ... but an isolated tornado or two may well occur.

... Poland ... Slovakia ... N Hungary ...

The level one area needed to be expanded northwards into Poland where rather decent shear turned out to be present. Severe threat will be less robust than farther south, but isolated severe wind gusts and marginally severe hail may well occur.

... North Sea coast ...

Soundings from the North Sea coast confirm the threat for isolated tornadoes given strong LL buoyancy. Locally, strong LLS is present, hinting at the possibility of storm-scale rotation that could also be contracted into a tornado.