Forecast Update
Valid: Fri 08 Jun 2007 14:00 to Sat 09 Jun 2007 06:00 UTC
Issued: Fri 08 Jun 2007 14:31
Forecaster: TUSCHY

SYNOPSIS

Please refer to the outlook issued at Thu 07 Jun 2007 21:25 !

DISCUSSION

... Belgium and the Netherlands ....

The latest soundings over the area of interests reveal high to extreme instability values ( e.g. De Bilt at 12Z with 1500 J/kg MLCAPE and 4000 J/kg SBCAPE ! ).

Only marginal asymmetric anvils indicate still very weak shear, but storms in such a favorable thermodynamic environment can produce hail , matching our severe criterion... we even do not want to exclude a significant hail report over western Belgium and the Netherlands during the later afternoon and evening hours, where DLS will reach 10-15m/s and SRH3 values will start a slow increase.
Although LCLs went up during the strong, dirunal driven mixing process, slow BL cooling during the evening hours should help to reduce T-Td spread and an isolated tornado report can't be excluded.

High PWAT values and slow storm motion / tendency to clustering favor an enhanced excessive rainfall risk.

12Z sounding of Praha indicates the potential for strong downdrafts, locally matching the severe criteria, but isolated nature of storms would not justify a level-1.

Otherwise, no significant changes were made and more details can be found in today's outlook.