The example shown here corresponds to an episode that took place between 1 and 5 december 2001. This event is characterized by an intense cyclogenesis which starts on day 2 at 06 UTC near Creta island. Soon after its formation, the main cyclone absorbs a pre-existing one that between 29 november at 00 UTC and 1 december at 12 UTC was "walking around" over the area in between Creta, Turkey and Cyprus. The tracks of both cyclones, the previous one, in blue, and the main one, in red, are presented.

Also, on page two, the time evolution of total circulation at surface (in 10exp(7)m2/s) for both cyclones can be seen. The previous cyclone keeps a more moderate circulation, below 6 units. The development phase of the main cyclone is between its appearance (1-12-00Z) and 2-12-06Z. During this period the cyclone increases its circulation from 4 to nearly 10 units. By the time when the heavy rains and floods take place over Israel, the main cyclone is still quite intense: 7-8 units of circulation.

During the decaying phase of the main cyclone torrential rains over Israel were produced with a max of 250 mm in 36 hours, and several floods around the country. [Check figure on page 3: (left) rain fallen from 3-12-18Z to 4-12-06Z over Israel; (right) same from 4-12-06Z to 5-12-06Z (right)].

The torrential rains take place when the main cyclone (red track) is located over Ciprus. The cyclonic circulation advects over Israel a moist Mediterranean air mass, which originally came from the Atlantic (see page 5).

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