Mediterranean Climatology

Within the Mediterranean basin, the gale-force occurrences of wind types predicted by MEDEX have two distinct seasons: "winter" (October 1 through May 31) and "summer" (June 1 through September 30). MEDEX contains a rule base to handle each season. A climatology of these wind events is displayed below and is divided between the two seasons.

The winter season is associated with more active weather and a complexity of ridges and troughs at the 500 mb level, as shown in 500mb_type flow patterns. The summer season is associated with relatively calm conditions both at the surface and the 500 mb level. The occurrences and strengths of the MEDEX winds vary between winter and summer. A 14 month climatology of MEDEX winds depicts the seasonal differences.

Forecasters implementing MEDEX need to understand the following.

• MEDEX predicts gale-force onset/continuation and cessation for 6 wind types during the winter season and 3 wind types during the summer season (shown below).
• There is a transition period between each season (May-June and September-October). Users should be cautioned when forecasting during the transition periods for several of the wind types. Bora--Adriatic Sea and Bora--Aegean Sea occur primarily during the coldest part of the winter season while the Etesian occurs primarily during the hottest part of the summer season (August and September).

Climatology of Gale Force Wind Events - Collected from 14 Feb 1995 through 10 April 1996
[A gale-force wind event (occurrence) was expertly determined every 12 h using a variety of environmental data along with SSM/I surface wind speed data.]