Characteristics of monsoonal thunderstorms in Arizona and New Mexico

Monsoonal convection in the southwest United States remains difficult to forecast and at times difficult to observe due to large areas of complex terrain with little population and sparse data. Using 10 years of data from the Tropical Rainfall Measuring Mission (TRMM) satellite, a climatology of monsoonal precipitation is created. The diurnal cycle, typical locations of precipitation, and characteristics that can be used to infer convective strength are used to understand the development and evolution of monsoon precipitation in Arizona and New Mexico. Additionally, NEXRAD radar data are used to fill in temporal gaps in data from TRMM as well as to provide information on individual features for an example case. Because stronger thunderstorms occur most frequently during monsoonal burst periods, the TRMM 3B42 algorithm is used to create a new and more complete definition of break and burst periods during the TRMM period of record, and composite soundings are used to describe the thermodynamic differences during burst and break periods. The North American Regional Reanalysis (NARR) is also utilized to compare synoptic conditions during the TRMM break and burst periods to previous studies that defined break and burst periods in different ways. An example case from July 25, 2006 illustrates the type of intense thunderstorms that can occur within monsoonal burst periods and demonstrates the diurnal cycle and properties of convection observed using the TRMM climatology.