Extended Forecast
Valid: Sun 17 Feb 2008 06:00 to Mon 18 Feb 2008 06:00 UTC
Issued: Fri 15 Feb 2008 22:13
Forecaster: TUSCHY

Blocking weather pattern persists over Europe with a major upper-level trough over eastern Europe. Attendant CAA is underway and overspreads parts of the eastern Mediterranean during the forecast period.
Temperatures at 850hPa at or below -10°C reach Crete during the night hours. SSTs of 14°C and cold airmass create an environment with very steep lapse rates at all levels, resulting in a broad area of low-end instability release S / SE of Greece. Main concern right now is the moisture quality as this continental airmass is very dry. Mixing could occur and we decided to include a long fetch before a general thunderstorm area would be issued.Maximized instability release at lowest 2-3km and a weak background flow indicate a risk for waterspouts. A low freezing level also hints on a risk for small hail but otherwise no severe weather risk is expected.

Another area with numerous thunderstorms should exist west / southwest of Portugal where better instability will be present but weak shear should preclude thunderstorm organisation. The environment over south Portugal / SW Spain could become conducive for a few hail reports after midnight as mid-level lapse rates steepen and 0-3km helicity values increase to more than 300 J/kg. Main inhibiting factor will be meager instability release, but those areas have to be monitored.