NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1016 AM EDT WED JUN 06 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). ***


...SOUTHERN CALIFORNIA...

NAM SURFACE TEMPERATURES WERE INITIALIZED AS MUCH AS 20 DEGREES
TOO COLD WITHIN THE COACHELLA/IMPERIAL VALLEYS.

...SOUTHERN NEVADA...

NAM SURFACE TEMPERATURES WERE INITIALIZED AS MUCH AS 15-20 DEGREES
TOO COLD ACROSS SOUTHERN NEVADA...INCLUDING THE LAS VEGAS
METROPOLITAN REGION...INTO THE LOWER COLORADO RIVER VALLEY.

...OKLAHOMA...

THE NAM APPEARS TO BE UNDERESTIMATING THE INITIAL EXTENT AND
INTENSITY OF THE SHOWERS AND THUNDERSTORMS DEVELOPING AND MOVING
ACROSS WESTERN OKLAHOMA.

PEREIRA