NAM AIR QUALITY DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 952 AM EDT FRI AUG 10 2012 *** The following information pertains to initialization errors noted on the 12Z NAM that may negatively impact the performance of the 12Z CMAQ output as used for air quality forecasting. Specifically, errors that apply to temperature, winds, relative humidity and precipitation are included. This discussion only applies to geographical regions of the CONUS where air quality is currently forecast to be degraded (i.e. CODES: YELLOW/ORANGE/RED/PURPLE/MAROON). *** INTERIOR VALLEYS OF CALIFORNIA... DESERT SOUTHWEST... THE NAM INITIALIZED SURFACE TEMPERATURES AS MUCH AS 15 DEGREES TOO LOW NEAR THE MOUNTAINS DUE TO ITS TERRAIN RESOLUTION. SNAKE RIVER VALLEY OF IDAHO... NORTHERN WASATCH FRONT... THE NAM INITIALIZED SURFACE WINDS AS MUCH AS 10 DEGREES TOO LOW IN SPOTS. FRONT RANGE OF COLORADO... THERE WERE NO SIGNIFICANT INITIALIZATION ERRORS NOTED WITH THE NAM IN THIS REGION. CENTRAL OKLAHOMA... EAST TEXAS... THERE WERE NO SIGNIFICANT INITIALIZATION ERRORS NOTED WITH THE NAM IN THESE REGIONS. CISCO