NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1027 AM EDT THU JUN 28 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...

SURFACE TEMPERATURES ARE ANALYZED IN THE NAM AS 5 TO 15F COOLER
THAN OBSERVED ACROSS MUCH OF THE MOJAVE DESERT...SOUTHERN SIERRA
NEVADA RANGE...AND PORTIONS OF THE SAN JOAQUIN VALLEY.  WINDS ON
THE NAM WERE WERE 5-10 KNOTS TOO WEAK ACROSS SOUTH-CENTRAL
CALIFORNIA AND NEAR LAS VEGAS.


...NORTHERN UTAH/CENTRAL COLORADO/NEW MEXICO...

THE NAM WAS 10F TOO COOL NEAR SALT LAKE CITY AND IN PORTIONS OF
CENTRAL COLORADO.  THE NAM WAS 10F TOO WARM IN SOUTHERN COLORADO. 
THE NAM APPEARS 150 MILES TOO FAR SOUTH WITH ITS AREA OF SHOWERS
NEAR THE COLORADO/UTAH BORDER.


...PLAINS/MIDWEST EASTWARD...

THE NAM WAS 5-10F TOO WARM ACROSS PORTIONS OF EASTERN
OKLAHOMA...SOUTHWEST ARKANSAS...THE NORTHERN ALABAMA/GEORGIA
BORDER...AND PORTIONS OF THE SOUTHERN APPALACHIANS.  ACROSS MUCH
OF EASTERN TEXAS AND SOUTHEAST OKLAHOMA...THE WINDS ARE MORE
EASTERLY THAN THE NAM INDICATED.  THE NAM WAS 5-10 KNOTS TOO WEAK
WITH THE WINDS IN CENTRAL KANSAS...SOUTH-CENTRAL
MISSOURI...SOUTHERN IOWA...SOUTHERN MINNESOTA...CENTRAL
INDIANA...AND NEAR THE WESTERN VIRGINIA/NORTH CAROLINA BORDER. 
THE NAM DID NOT SPREAD THE LIGHT RAIN FROM IOWA FAR ENOUGH
NORTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY.


ROTH