NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1021 AM EDT WED JUL 20 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 SOUTHERN CALIFORNIA...
...DESERT SOUTHWEST...

THE NAM INITIALIZED AS MUCH AS 20 DEGREES TOO COOL NEAR THE
MOUNTAINS...A CONSEQUENCE OF ITS TERRAIN RESOLUTION.  ALSO...THE
MODEL INITIALIZED AS MUCH AS 10 KNOTS TOO LIGHT WITH LOW LEVEL
WINDS ACROSS PORTIONS OF THESE REGIONS.


...FRONT RANGE OF NORTHERN AND CENTRAL COLORADO...

THE NAM INITIALIZED OVER 15 DEGREES TOO COOL NEAR THE
MOUNTAINS...A CONSEQUENCE OF ITS TERRAIN RESOLUTION. 
OTHERWISE...THERE WERE NO SIGNIFICANT INITIALIZATION ERRORS NOTED
WITH THE MODEL.


...CENTRAL GREAT LAKES...
...OHIO VALLEY...
...CENTRAL MISSISSIPPI VALLEY...

THE NAM DID NOT RESOLVE THE SWATH OF SHOWERS EXTENDING FROM LAKE
SUPERIOR INTO THE LOWER PENINSULA OF MICHIGAN THIS MORNING. 
OTHERWISE...THERE WERE NO SIGNIFICANT INITIALIZATION ERRORS NOTED
WITH THE MODEL.


...MID ATLANTIC STATES...
...SOUTHEAST STATES...

THE NAM OVERSTATED THE EXTENT OF SHOWERS ACROSS THE SOUTHERN
APPALACHIANS THIS MORNING.  OTHERWISE...THERE WERE NO SIGNIFICANT
INITIALIZATION ERRORS NOTED WITH THE MODEL.


CISCO