NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1006 AM EDT WED JUL 04 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.

...SOUTHERN NEVADA...

THE 12Z NAM INITIALIZATION DEPICTED TEMPERATURES APPROXIMATELY
10-15 DEGREES TOO COOL ACROSS SECTIONS OF SOUTHERN
NEVADA...INCLUDING THE LAS VEGAS METRO REGION.  WIND SPEEDS WERE
INITIALIZED 10 KTS TOO WEAK ACROSS THE REGION AS WELL. 

...WESTERN COLORADO...

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

...LOWER GREAT LAKES REGION...

THE NAM DOES NOT APPEAR TO HAVE A GOOD INITIAL HANDLE ON THE
SHOWERS AND THUNDERSTORMS DROPPING SOUTHEASTWARD FROM THE SOUTHERN
TIP OF LAKE HURON INTO CENTRAL LAKE ERIE...UNDERESTIMATING THEIR
INTENSITY AND SOUTHERN PROGRESS.

PEREIRA