NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1015 AM EDT WED JUN 27 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). ***


...CALIFORNIA/DESERT SOUTHWEST...

TEMPERATURES NEAR THE SURFACE ARE ANALYZED IN THE NAM AS 5 TO 15 F
COOLER THAN OBSERVED AT SOME LOCATIONS OVER INTERIOR SOUTHERN
CALIFORNIA.


...CENTRAL COLORADO...

THE NAM ANALYSIS OF NEAR-SURFACE TEMPERATURES SHOWS ERRORS AS HIGH
AS 5 TO 10 F... EITHER TOO WARM OR COOL DEPENDING EXACT LOCATION. 
ALSO THE NAM LOW LEVEL WIND ANALYSIS SHOWS FLOW FROM THE
WEST-SOUTHWEST AT 5 KTS OVER EAST-CENTRAL COLORADO WHERE A COUPLE
SITES REPORT WINDS FROM THE NORTH AT 5 TO 10 KTS.


...SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY...
...EASTERN PLAINS/MID-UPPER MISSISSIPPI VALLEY...

THE NAM DISPLAYS NO SIGNIFICANT INITIALIZATION ERRORS.


...LOWER GREAT LAKES/OHIO VALLEY...
...TENNESSEE VALLEY INTO THE SOUTHEAST...

THE NAM DISPLAYS NO SIGNIFICANT INITIALIZATION ERRORS.


RAUSCH