Foroozan Arkian and Mahnaz Karimkhani
The structure of five flood-producing storms was analyzed in northwestern Iran. The storms contained several coexisting convective cells during analysis period. We tried to obtain knowledge of Intensity, Duration and Type (IDT) of the storms by radar images and verify some convection-related parameters such as K, Showalter, Total- Total, Helicity and Energy-Helicity (EHI) indices; Convective available potential energy (CAPE) and Bulk Richardson number (BRN) in the area. The surface and upper air data were taken from General Forecast System (GFS) with spatial resolution of 0.5°×0.5° and a temporal resolution of 6 h. Results show, the CAPE values for thunderstorms are equal zero or less than 1000 Jkg-1 even for super and multi cells in the area. The most flood producing thunderstorms was single or multi cell and those merges together and makes Complex cell. One of the cases was twin squall lines that accompanied with cold front. Super-cell without Tornado sign was very infrequent. The growth of vertical cell in radar images has the direct relationships with convective available potential energy.