On the cloud microphysical processes during the November 2, 1994 hazardous storm in the southeastern Mediterranean as simulated with a mesoscale model

A mesoscale model (CSU RAMS) model with cloud microphysics is used for analysis of the November 1–2, 1994 weather developments over the eastern Mediterranean (EM). The hazardous weather processes of the period are successfully simulated. According to observations, as well as the modeling results, the main areas with very intensive precipitation were located over Egypt and southern Israel. Results of the simulation are used to evaluate the role of the cloud microphysics of the storm. Analysis of time variations of the model, derived from microphysical characteristics, is made at several locations along the path of the storm. The processes at the locations represent different stages of the storm development. sults show that during this intense storm, cloud microphysical processes experienced at least two phases of development. During the first phase, which was associated with initiation and intensification of the mesoscale convective system (MCS), the condensate, mainly composed of cloud water, existed in the deep layer from 3 to 10 km. It was evidently formed by condensation and collection processes in the slowly developing updrafts. During the second phase, associated mainly with frontal type cloud developments, the clouds were much less vertically developed and were characterized by less intense cloud processes. Pristine ice particles were found at about 10 km during most of the period. Vertical development of the clouds was less active than during the first stage. Observed rapid decrease of the rain intensity over Israel was mainly a consequence of the transformation process. At the same time, the increase in dustiness of the air over the region during this time could also have contributed to this decrease although the role of this factor is not completely clear.