Abstract:A rainstorm process with long duration occurred in Liaoning province during 1-2 July, 2013, which can be divided into three stages, including two warm area precipitation cases and a frontal and warm area precipitation coexistence case. The northwest rain band is formed by the warm area precipitation in stage one and the frontal precipitation in stage three, while the southeast rain band is formed by the warm area precipitation in stage two.Based on the NCEP/NCAR reanalysis data, the conventional automatic weather station data, the intensive automatic station data and the satellite data, the generation mechanism of each precipitation and the main physical difference between the generating process of frontal precipitation and the warm area precipitation were analyzed in detail.Results show that warm area heavy rain mainly occurs at the cold wet side of dry line or near surface convergence line, and since the characteristics of high temperature and humidity in warm area, the precipitation in this area is generally stronger than that in the nearby frontal area. In addition, there are many differences between warm area precipitation and frontal precipitation in triggering mechanism, mesoscale environmental conditions, dynamic and thermal structures.