Origin of winter precipitation in the central coastal lowlands of Saudi Arabia

The area under investigation is situated at the Gulf coast in Saudi Arabia north of Jubail Industrial City. The region is characterized by a Mediterranean climate regime displaying a hot and dry summer season and a cooler winter period with rainfall. The analysis of regional climate data was based on the measurements of three weather stations during three winter periods. For further analysis GMS 5(col) IR and MET5/7 IR satellite images were used in order to locate tracks of cyclones and cloud formations. During the observation period four different types of precipitation occurred: (1) cyclones from the Mediterranean Sea; (2) convection cells; (3) the formation of new cyclonic depressions in front of the Zagros Mountains above Iraq and eastern Iran; (4) currents from equatorial areas in Sudan and Ethiopia. The study demonstrates that apart from the well-known Mediterranean depressions there are at least three more characteristic weather situations, which may provide rain for the Eastern Province of Saudi Arabia. (C) 2003 Elsevier Ltd. All rights reserved.