NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1042 AM EDT FRI AUG 31 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). ***


...MIDDLE ATLANTIC...

NO NAM INITIALIZATION ERRORS WERE NOTED.

...NORTHEAST...

ACROSS CENTRAL NEW YORK THE NAM TEMPERATURES ARE POORLY
INITIALIZED...WITH STARTING TEMPERATURES AS MUCH AS 5-10 DEGREES
TOO COLD.  THE NAM APPEARS TO BE UNDERDONE WITH THE RAINS MOVING
EASTWARD ALONG THE NEW YORK/CANADIAN BORDER THIS MORNING. 

...UPPER MIDWEST TO OHIO VALLEY...

NO NAM INITIALIZATION ERRORS WERE NOTED.

...SOUTHERN PLAINS...

NO NAM INITIALIZATION ERRORS WERE NOTED.

...COLORADO FRONT RANGE...

THE NAM IS INITIALIZED WITH LIGHT SOUTHWESTERLY TO WESTERLY WINDS
ACROSS MUCH OF EASTERN COLORADO.  OBSERVATIONS THIS MORNING
INDICATE MUCH MORE VARIANCE IN THE LOCAL WIND FIELD WITH SOME
STATIONS REPORTING WINDS OUT OF THE NORTH THIS MORNING.

...IDAHO SNAKE RIVER PLAIN...

THE NAM IS INITIALIZED WITH LIGHT EASTERLY WINDS ACROSS MUCH OF
THE REGION.  OBSERVATIONS THIS MORNING INDICATE MUCH MORE VARIANCE
IN THE LOCAL WIND FIELD WITH SOME STATIONS REPORTING WINDS OUT OF
THE NORTH THIS MORNING.

...CALIFORNIA/NEVADA AND SOUTHERN ARIZONA...

THE NAM IS INITIALIZED WITH LIGHT UNIFORM WESTERLY WINDS ACROSS
MUCH OF THE SAN JOAQUIN VALLEY.  OBSERVATIONS INDICATE MUCH MORE
VARIANCE IN THE LOCAL WIND FIELD WITH DIRECTIONS DIFFERING BY AS
MUCH AS 90 DEGREES.  ACROSS THE SACRAMENTO VALLEY THERE ARE
DIRECTIONAL DIFFERENCES AS WELL...WITH OBSERVATIONS ALSO DIFFERING
BY AS MUCH AS 90 DEGREES FROM THE SOUTHERLY WINDS WITH WHICH THE
NAM IS INITIALIZED.  THERE ARE ALSO SPEED DIFFERENCES AS
WELL...WITH OBSERVATIONS SHOWING WIND SPEEDS AS MUCH AS 10 KTS
GREATER THAN THE NAM INITIALIZATION.

PEREIRA

*** This will be the final NAM Air Quality Diagnostic Discussion
issued for the 2012 season.  ***