NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1013 AM EDT THU JUL 14 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). ***



...THE TENNESSEE VALLEY...

BASED ON RADAR...THE NAM APPEARS TO HAVE OVERSTATED THE EXTENT OF
SHOWER ACTIVITY ALONG THE COLD FRONT SETTLING THROUGH THIS REGION
EARLY TODAY.  OTHERWISE...NO SIGNIFICANT INITIALIZATION ERRORS
WERE NOTED OVER THE REGION.


...LOWER COLORADO VALLEY...

THE NAM INITIALIZED AS MUCH AS 15 DEGREES FAHRENHEIT TOO LOW WITH
SURFACE TEMPERATURES NEAR THE MOUNTAINS...DUE TO COARSE TERRAIN
RESOLUTION.  ALSO...THE MODEL WAS 10 TO 15 KNOTS TOO LOW WITH THE
10-METER WINDS ASTRIDE THE NEVADA BORDER.


CISCO
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