Forecast Update
Valid: Mon 19 Jun 2006 13:00 to Tue 20 Jun 2006 06:00 UTC
Issued: Mon 19 Jun 2006 14:07
Forecaster: VAN DER VELDE

SYNOPSIS

see forecast

DISCUSSION

...southern Norway into Sweden...

12Z Stavanger sounding has reasonably deep CAPE and impressive shear and low-level veering, with 5 kts east at surface, 30 kts south at 850 and 50 kts southwest at 500 hPa. This support supercells with a threat of large hail, severe gusts and also tornadoes are not excluded, especially with this low level shear magnitude and veering and low LCLs. Forcing mechanism is a bit lacking for widespread convection. Upgraded to level 1.


...Eastern central Germany, western Czech Republic...

12Z soundings have shown considerable CAPE and a reasonable amount of shear. Do not expect more than isolated large hail and perhaps a marginally severe gust. Upgraded to a level 1.

...northern Spain into French Massif Central...

12Z soundings in northern Spain seem unimpressive instability and shear wise. Lyon sounding is very dry in lower levels. Downgraded these parts.

...northern Italy...

Downgraded the area because 12Z soundings were rather dry, though shear and helicity are excellent.

...eastern Austria...

Strong instability and even good veering winds with 30 kts at 600 hPa in Vienna 12Z sounding suggests strong, maybe even rotating thunderstorms are possible, if the cap manages to erode a bit. The forcing should come from orography. Upgraded this to level 1.

...Ukraine...

Upgraded to level 1 because of large hail reports of previous days in similar situation. Shear is moderate and can support long lived clusters with a threat of large hail and severe gusts.