NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1036 AM EDT WED AUG 29 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). ***


...UPPER MIDWEST TO TENNESSEE/OHIO VALLEYS...
NO NAM INITIALIZATION ERRORS WERE NOTED.

...SOUTHERN PLAINS...
THE NAM WAS 5-10F TOO COOL OVER SOUTHERN OKLAHOMA COMPARED TO
OBSERVATIONS NEAR THE RED RIVER.

...INTERMOUNTAIN WEST AND COLORADO FRONT RANGE...
THE NAM ANALYZED TEMPERATURES ABOUT 10-15F TOO COOL WEST OF SALT
LAKE IN PORTIONS OF NORTHWESTERN UTAH. THE NAM ALSO ANALYZED
TEMPERATURES 5-10F TOO ALONG WESTERN PORTIONS OF THE SNAKE RIVER
VALLEY IN IDAHO. THE NAM WINDS WERE ABOUT 10 KT TOO WEAK COMPARED
TO OBSERVATIONS IN PORTIONS OF THE SNAKE RIVER VALLEY AND SAWTOOTH
MOUNTAINS IN IDAHO.

...ARIZONA/SOUTHERN NEVADA/CALIFORNIA...
THE NAM ANALYZED TEMPERATURES TEMPERATURES 5-10F TOO COOL ACROSS
THE DESERTS OF EASTERN CALIFORNIA...SOUTHERN NEVADA...INTO EXTREME
WESTERN ARIZONA. THE NAM ALSO ANALYZED TEMPERATURES ROUGHLY 5-10F
TOO COOL ACROSS THE SAN JOAQUIN VALLEY AND THE RENO NV METRO
REGION. ANALYZED TEMPERATURES FROM THE NAM WERE ABOUT 15F TOO WARM
IN AND AROUND THE LAKE TAHOE REGION. 12Z WINDS FROM THE NAM WERE
ABOUT 10 KT TOO WEAK COMPARED TO OBSERVATIONS ALONG THE SOUTHERN
CALIFORNIA/NEVADA BORDER.

OTTO