NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1026 AM EDT THU JUN 14 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...
...LOWER COLORADO VALLEY...

THE NAM INITIALIZED SURFACE TEMPERATURES AS MUCH AS 10 TO 15
DEGREES TOO LOW NEAR THE EDGE OF THE TERRAIN OVER SOUTHERN
CALIFORNIA...MOST LIKELY DUE TO ELEVATION RESOLUTION WITHIN THE
MODEL.


...NORTHERN FRONT RANGE OF COLORADO...

THE NAM INITIALIZED LOW LEVEL NORTH WINDS AS MUCH AS 10 TO 15 KTS
TOO LIGHT OVER THE REGION.


...TENNESSEE VALLEY...
...OHIO VALLEY...
...SOUTHEAST PIEDMONT...

THERE WERE NO SIGNIFICANT INITIALIZATION ERRORS NOTED WITH THE NAM
IN THESE REGIONS.


CISCO