One of the most severe snowstorms in recent years occurred in Tehran region on 28 January 2018 and led to closure of airports and roadblocks. In this study, various factors of the formation and development of the snowstorm have been investigated through synoptic and mesoscale analyses. At first, a synoptic analysis was carried out using the reanalysis FNL data with horizontal resolution of . Then, the snowstorm was simulated utilizing WRF model configured for two nested domains with horizontal resolutions of 9 and 3 km using ERA5 data as initial and boundary conditions. The synoptic analysis showed that the surface cyclone and mid-tropospheric trough causing positive vorticity advection, associated with cold air and moisture advections are important factors in developing the snowstorm. The high resolution simulation results also illustrated that the strong frontogenesis in the lower and middle troposphere coincided with a deep layer of negative equivalent potential vorticity (EPV) in the troposphere during the development and maturity stages of the snowstorm. Therefore, the main conclusion is that the intense frontogenesis accompanied with a deep layer of negative EPV can explain the evolution of the meso-scale snowstorm.