A Synoptic Analysis of Thunder Rainfalls in Aras River Southern Basin

The main aim of this article is the synoptic study of thunderstorm ram falls in southern Aras basin. For this purpose, we extracted thunder and shower rainfalls of six stations of Maku, Khoy, Ardebil, Parsabad, Ahar and Jolfa for the time period of 1986-2003. Using synoptic maps, we analyzed those shower rainfalls resulting from cold front entrance in stations under study. Results indicated that the most important causes of shower rainfalls in this region are two factors, namely, local instability caused by local factors during warm seasons and the entrance of cold fronts to the area during cold seasons. Among the stations studied, Maku receives more precipitation thanks to its higher elevation, and also locating on the path of western atmospheric system.