A Synoptic Study of Heavy Rain in Southern Regions of Bushehr Province

Heavy rains are one of the features of arid and semi-arid climates which result in flood. This kind of rainfall originates from environmental and synoptic conditions. Mediterranean cyclones are the major factors in heavy rainfall in Iran, but these cyclones do not happen in some parts of Iran such as Southern and Southeastern areas. In this study, it has been tried to pinpoint the synoptic reasons of heavy rainfall in Southern regions of Bushehr province through the analysis of the relationship between this rainfall in Bushehr province and atmospheric system over Iran and the areas around it. The findings of this study show that the major cause of heavy and torrential rains is the arrival of Sudanese low pressure system in this region from the South and Southwest. Albeit, if the ascent local conditions such as heat occur, the heaviest rains happen in Southern regions of Bushehr province. In fact, this kind of rainfall in this area has a Sudanese origin and if it is accompanied by Mediterranean system, heavier rain falls.