Monthly synoptic patterns associated with wet/dry conditions in the Eastern Mediterranean

An investigation of the main features of large-scale synoptic patterns over Europe and the adjacent areas for extreme winter periods during 1980-1995 over the Eastern Mediterranean (EM) is performed. The NASA reanalysis data set is used to investigate composite sea level pressure (SLP), geopotential height of the 500hPa surface (H-500) and precipitation-wet, normal and dry patterns for each month during the period October-March. It is found that the wet and dry cool seasons in the EM are associated with distinct SLP and H-500 anomaly patterns over Europe and the adjacent regions. During the dr y spells large-scale positive SLP/H-500 anomaly areas prevail over Eastern Europe. A negative SLP anomaly is normally found during these periods over southwestern and Western Europe. During the wet cool seasons in the EM ther e are mainly negative SLP/H-500 anomaly areas over Eastern Europe to the no rth east of the EM. Positive SLP/H-500 anomalies are found over Western Eur ope. During wet months a trough zone between the Siberian and the Azorean H ighs is positioned over the eastern part of the Mediterranean. During dry months the Siberian anticyclone is more intensive and the zone w ith low surface pressure is displaced to the central part of the northern M editerranean.