EASTERLY WIND STORMS OVER ISRAEL

Continental wind storms are common along the Mediterranean coast. Alon g the northern coast they are mostly cold, similar to the Bora or the Mistral, and along the southern coast they are mostly warm, e.g., the Ghibli or the Shirocco. At the eastern Mediterranean basin and the Lev ant region, these storms are intermittently warm and cold during the s ame season and often even during the same event. Quasistationary syste ms, as well as moving disturbances, are the cause of such wind storms. Accordingly, the resulting weather conditions may be extremely conver se due to the characteristics of the advected airmass. Specific region s in Israel, sensitive to easterly storms, are influenced by these win d storms for about 10% of the year (e.g., the westerly slopes of the m ountains and valleys with west-east orientation). The frequency, howev er, of widespread storms covering the entire region is only approximat ely 1.4% of the entire year. These wind storms are therefore classifie d in the present study according to their climatological and synoptic characteristics; indicating that the dominant synoptic situation is th e Red-Sea trough and the warm advections. These storms appear only fro m October-May and are most frequent during the cold season. The diurna l course is characterized by a strengthening in the morning hours and a weakening at noon and in the afternoon hours, due to the opposing ef fect of the westerly sea breeze, suppressing the easterly winds and th e effect of katabatic winds. Nevertheless, synoptic conditions may con tribute to this tendency as well. Accordingly, a significant increase in the frequencies of easterly storms, in relation to distance from th e seashore has been identified. Although most of the stormy days are w ith westerly winds, the easterly wind storms has vast environmental im plications, creating damage especially to agriculture and occasionally also to property and life; coastal flooding, potential air pollution, intensifying of forest fires and occasionally dust and sand storms.