Previous statistical analyses performed by the authors have demonstrated an anti-correlation between dust storms and precipitation during the North American Monsoon. During monsoon season both precipitation and dust storms appear to be associated with a moisture inflow approaching from Gulf of California (GOC) labeled as a “moisture surge.” A series of meteorological observations are presented in an effort to establish a connection between dust storms and reduced precipitation amounts in El Paso, Texas and surrounding areas in the presence of Gulf of California moisture surges. Surface observations, soundings, and upper atmosphere circulation features have been analyzed throughout the North American Monsoon over a period of eight years (1998 – 2006).

Ground measurements of dew point temperature, wind speed, and wind direction were obtained from the Texas Commission on Environmental Quality (TCEQ). Surface aerosol mass densities were obtained from TCEQ and size resolved number concentrations were obtained utilizing the CLIMET CI-550 laser particle counter. Precipitation data and soundings were obtained from the National Weather Service and Comisión Nacional del Agua (México). In addition, NCEP-NCAR reanalysis data was used to identify upper atmosphere circulation features. These data sets were utilized (1) to recognize GOC moisture surges, (2) to investigate whether increased aerosol mass and number densities were responsible for decreased precipitation amounts, and (3) to evaluate atmospheric conditions during a moisture surge in the Paso del Norte region.