NAM AIR QUALITY DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 1029 AM EDT THU AUG 02 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... THE NAM INITIALIZES TEMPERATURES 7 TO 15 DEGREES TOO COOL IN THE VALLEYS EAST OF LOS ANGELES. ACCORDINGLY...WINDS IN THE VALLEYS EAST OF LOS ANGELES ARE NORTHWESTERLY AT 10 TO 15 KNOTS WHILE NAM WINDS ARE FROM THE WEST AT LESS THAN 5 KNOTS. JAMES/HURLEY