in order to understand the dynamic structure of the atmosphere at the time of heavy rainfall in western Iran, two databases were used. First, by examining 14 synoptic stations of the Meteorological Organization located in the region, from 1990 to 2012, inclusive rainfall with more than 20 mm was extracted in the region. In the next step, by referring to the website of the European Center, the weather forecast (ECMWF) with a horizontal resolution of 0.125 × 0.125 degrees was obtained. Dynamic equations such as potential equilibrium on compression surfaces, fronting, partial equilibrium subsidence, and moisture flux convergence were used for the analyzes. The results showed that during the occurrence of heavy and pervasive rains, very deep boats with a depth of more than 20 degrees are formed and systems such as low polar pressure expand in the middle level. At this time, while forming low shear pressures on the region, the potential value values ​​on the 330 ° K conjugate surfaces, in areas such as the Mediterranean, Black, and Red, to more than PVU 6 and on the study area to more than PVU 3 Arrives. This situation on the ground also helps to reduce low pressures and reinforce instabilities. So that by examining the relative equilibrium advection, the maximum positive values ​​of this index correspond to the western regions of Iran and eastern Iraq, which plays a very important role in the development of systems. In the upper layers and at the level of 250 hPa, due to the anomalies in the compression vestibule, the flow of the polar side jet expands to lower latitudes and merges with the polar side jet in the Middle East and Iran. These conditions have played a significant role in intensifying instability in the region. In the study of moisture sources, two sources were identified as main sources and two sources as sources of heavy rainfall, namely the Red Sea and the Mediterranean Sea (as the main source) and the Persian Gulf and the Black Sea (as moisture booster). ) Are considered.