عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This research is investigated the precipitation system which created the significant rainfall and flooding in the southern and southwestern of Iran on the 14 and 15th March 2014, with using Metar and Synop reports from the synoptic stations of southern provinces; and weather patterns such as: mean see level pressure - advections of humid, temperature at 1000, 850 and 500 hpa - the pressure tendency over 24 hours at 500 hpa; wind field at 1000 and 200 hpa - and jet stream at 200 hpa. This rainy system was compared with the system of March 1996, which it had the second largest maximum rainfall in this region during the past 58 years. The weather patterns of March 2014 are quite different from patterns of March 1996. The first case has been created by potential instability due to the dynamic low pressure, but the latter has been formed by the combination of Mediterranean low pressure and Sudanese low. Of course, the gradual meridianization of the strong sub-tropical jet stream in the northwestern part of Africa, and penetration of its branch over the Persian Gulf have helped to intensify the instability of these areas on the mentioned days.
The Maximum 24-hour rainfall has been reported from Bandarabbas, Rudan and Kahnuj stations that their amount was respectively 110, 78.5 and 69 mm. Three stations located in the easterly flank of precipitation system where there was the abundant moisture nutrition from the Strait of Hormuz.
The left exit region of sub-tropical jet stream was situated over the hormozgan province and caused the lifting air flow in the region. The sum of these factors have caused the maximum rainfall occurs in this province