NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1007 AM EDT WED JUL 11 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...

THE 12Z NAM INITIALIZED SURFACE TEMPERATURES 10 TO 15 DEGREES TOO
COOL IN THE DESERT AREAS EAST OF LOS ANGELES. THE MODEL
INITIALIZATION WAS MUCH CLOSER TO THE OBSERVATIONS IN THE COASTAL
AREAS OF SOUTHERN CALIFORNIA...AS WELL AS THROUGH THE CENTRAL
VALLEY AND THE REST OF CENTRAL AND NORTHERN CALIFORNIA.

...SALT LAKE CITY UTAH...

THE 12Z NAM INITIALIZED 5 TO 10 DEGREES TOO COOL IN THE IMMEDIATE
VICINITY OF SALT LAKE CITY DOWN TO PROVO.

BURKE/MUSHER