NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1017 AM EDT THU JUN 30 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). ***


...MID ATLANTIC/TENNESSEE VALLEY/SOUTHEAST...
...GREAT LAKES/OHIO VALLEY...

NO SIGNIFICANT INITIALIZATION ERRORS ARE NOTED.


...MISSISSIPPI VALLEY...
...EAST-CENTRAL PLAINS TO WESTERN GULF COAST...

OVER LOCALIZED AREAS OF SOUTHWESTERN WISCONSIN THE NAM ANALYSIS
SHOWS WINDS FROM THE SOUTH-SOUTHEAST IN CONTRAST TO OBSERVATIONS
THAT SHOW WINDS FROM THE EAST.  MEANWHILE ALONG PORTIONS OF THE
WESTERN HALF OF THE LOUISIANA COAST THE NAM ANALYZES VERY LIGHT
ONSHORE FLOW VERSUS OBSERVATIONS THAT HAVE STRONGER ONSHORE WINDS
OF ABOUT 10 KTS.


...SOUTHWEST/CALIFORNIA...

THE NAM HAS ANALYZED TEMPERATURES 5 TO 15 DEGREES F LOWER THAN
OBSERVED AT SOME INTERIOR CALIFORNIA LOCATIONS.  NAM TEMPERATURE
INITIALIZATION ERRORS REACH ABOUT 15 TO 20 F TOO LOW VICINITY OF
THE SOUTHERN CALIFORNIA/NEVADA BORDER.  


RAUSCH