Mesoscale Convective Systems occurred in Northwestern Mexico during NAME

A survey of MCSs occurred during the North American Monsoon Experiment carried out in Northwestern Mexico in summer 2004 is presented. GOES 12 infrared images were used to locate MCSs. The period of study was July-August 2004. A number of 76 MCS were found in the studied period, 10% more than the 97-99 mean MCSs number, such that summer 2004 was an active year in Northwestern Mexico. In July 2004, occurred 41 MCSs with tracks mostly parallel to the Sonora and Sinaloa coastlines. Few moved toward Gulf of California. In August 2004 occurred 35 MCSs with tracks parallel to the Sonora coastline in the northern portion, and toward the Gulf of California in the southern portion of Northwestern Mexico. From the synoptic point of view, summer 2004 was dominated by a ridge at 500 hpa, located more southern than normal, which enhances formation of MCSs in this region.