NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1023 AM EDT TUE JUL 03 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). ***

...INTERIOR CALIFORNIA VALLEYS...

THE 12Z NAM INITIALIZATION DEPICTED TEMPERATURES APPROXIMATELY
10-15 DEGREES TOO COOL ACROSS SECTIONS OF THE THE INTERIOR
SOUTHERN CALIFORNIA VALLEYS.

...WESTERN COLORADO...

THE 12Z NAM INITIALIZATION DEPICTED TEMPERATURES THAT WERE AS MUCH
AS 10 DEGREES TOO LOW IN VALLEY AREAS OF WESTERN COLORADO.

...UPPER GREAT LAKES/MISSISSIPPI VALLEY...

THE NAM DOES NOT OFFER A GOOD REPRESENTATION OF THE FRONTAL
BOUNDARY INITIALLY EXTENDING NORTHWEST-SOUTHEAST ACROSS MICHIGAN
AND IN TURN DEPICTS WINDS THAT DIFFER 90-180 DEGREES FROM THE
OBSERVATIONS OVER PORTIONS OF LOWER MICHIGAN.  ALSO...THE NAM
INITIAL PRECIPITATION COVERAGE AND INTENSITY APPEARS TO BEEN
UNDERDONE ACROSS THIS REGION.

FURTHER TO THE WEST...THE NAM DOES NOT OFFER A VERY GOOD
REPRESENTATION OF THE MESCOSCALE BOUNDARY SLIDING SOUTHEAST ACROSS
SOUTHERN WISCONSIN/NORTHEASTERN IOWA AND HERE TOO DEPICTS WIND
DIRECTIONS THAT DIFFER FROM OBSERVATIONS AS MUCH AS 90-180 DEGREES
FROM OBSERVATIONS.

PEREIRA