Forecast Update
Valid: Tue 28 Aug 2007 18:00 to Wed 29 Aug 2007 06:00 UTC
Issued: Tue 28 Aug 2007 17:10
Forecaster: VAN DER VELDE

DISCUSSION

An update seems appropriate for the region of Massif-Central and western Alps.
12Z Lyon sounding showed potential for about 2000 J/kg CAPE to be released from the 850 hPa level. Though the surface temperatures will remain insufficient for surface-based convection, passage of mid level synoptic ascent in the 18Z-21Z time frame over the present surface convergence may be enough to trigger some storms. These may become supercells with chance of large/very large hail.