NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1020 AM EDT THU JUL 05 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 A FEW TEMPERATURES
APPROXIMATELY 5-10 DEGREES TOO COOL ACROSS SECTIONS OF THE THE
INTERIOR SOUTHERN CALIFORNIA VALLEYS.

...SOUTHERN NEVADA...

THE 12Z NAM INITIALIZATION DEPICTED TEMPERATURES APPROXIMATELY 5
TO 10 DEGREES TOO COOL ACROSS SECTIONS OF SOUTHERN
NEVADA...INCLUDING THE LAS VEGAS METRO REGION. 

...LOWER GREAT LAKES REGION...

THE NAM DOES NOT APPEAR TO HAVE A GOOD INITIAL HANDLE ON THE
SHOWERS AND THUNDERSTORMS DROPPING SOUTHWARD ACROSS NORTHERN OH
NOR WITH SHOWERS AND THUNDERSTORMS NOR WITH SHOWERS IN VICINITY OF
LAKE HURON/NORTHERN LOWER MI.  IN BOTH CASES IT APPEARS THAT THE
MODEL UNDERESTIMATED THEIR INTENSITY.

BANN