Synoptic analysis of thermodynamics destructive thunderstorms Ahvaz

Thunderstorms are destructive climatic phenomena that, recognition of mechanism, genesis and development of the thunderstorms could can be special very helpful in order to play against and reduce losses. In this study examined thunder storms with rainfall exceeding 10 mm in a 14-year period (2000- 2013) the Ahwaz region. Early identify the code for this event and then extract 10 mm of rain And were taken mean daily data of sea level pressure from NCEP / NCAR reanalysis data in 32 days. Finally, using principal component analysis (PCA) and cluster analysis, were classified circulation patterns of sea level which played a role in a rain thunderstorms. The study showed that the Ahwaz region of thunderstorm, has followed by general pattern. In the first pattern, in the SLP, low pressure systems Sudan with trough 1012 millibar with the passage over the Red Sea and the Persian Gulf advected hot and humid air to the study area and at 850 and 500 millibar level, the Ahwaz region is located in front of the trough 1500 geopotential heights and 5760 geopotential meter respectively.In the precipitation of this pattern, instabilities has continued to 500 millibar level. In the second pattern, the anticyclone tongue (flank) 1016 millibar that had spread from the East with the passage of the sea of Oman and the Persian Gulf led to the moisture advection was from study area and the 850 millibar level the study area located in front of the trough with geopotential height of 1500 to 1510 meter. Both the precipitation pattern, main source of moisture provide by Warm seas of the South and the major factor of uplifting provide by the western trough.