NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
957 AM EDT MON JUL 25 2011
 
*** 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 AS MUCH AS 20 DEGREES TOO COOL NEAR THE
MOUNTAINS...A RESULT OF TERRAIN RESOLUTION.  THE MODEL ALSO
INITIALIZED WINDS AS MUCH AS 10 KNOTS TOO LIGHT IN AREAS.


...FRONT RANGE OF COLORADO NORTH OF THE PALMER DIVIDE...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED WITH THE NAM IN
THIS REGION.


...OHIO VALLEY...
...MID ATLANTIC STATES...

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


CISCO