Fig. (2) Typical examples for the EM frequent (more than 5 days/year) synoptic classes as defined by Alpert et al. 2004. Each map is a SLP (hPa) map from a representative day (Osetinsky 2006). The frequency of each synoptic class (number of days per year) is denoted above each SLP map. The winter lows are presented in the first row: Low east deep (LE-D), Deep Cyprus low from the north (CLN-D), cold low from the west (LW). Highs are presented in the second row: High from the north (HN), High from the west (HW) and high over Israel (HC). Troughs are presented in the third row: Medium Persian trough (PT-M), Red sea trough to the east (RSTE) and Red sea trough center (RSTc). The subfigures were downloaded from http:// www.esrl.noaa.gov/ psd/ data/ gridded/ data.ncep.reanalysis.html