NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1041 AM EDT TUE AUG 28 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). ***


...TENNESSEE/OHIO VALLEYS...
NO NAM INITIALIZATION ISSUES WERE NOTED.

...MIDWEST TO UPPER MISSISSIPPI VALLEY...
THE NAM WAS UNDERDONE IN INTENSITY AND BETWEEN 100-200 MILES TOO
FAR NORTH WITH A DECAYING AREA OF PRECIPITATION MOVING THROUGH
SOUTHERN MINNESOTA BETWEEN 1200 AND 1400 UTC.

...SOUTHERN PLAINS...
THE NAM WAS OVERDONE WITH THE COVERAGE AND MAGNITUDE OF
PRECIPITATION ALONG THE RED RIVER INTO THE ARKLATEX.


...INTERMOUNTAIN WEST AND COLORADO FRONT RANGE...
THE NAM WAS ABOUT 5-10 TOO COOL ACROSS THE SALT LAKE CITY METRO
REGION. OTHERWISE...NO NAM INITIALIZATION ISSUES WERE NOTED.

...ARIZONA/SOUTHERN NEVADA/CALIFORNIA...
THE NAM ANALYZED TEMPERATURES 5-10F TOO COOL ACROSS THE DESERTS OF
EASTERN CALIFORNIA...SOUTHERN NEVADA INTO WESTERN ARIZONA. THE NAM
ANALYZED TEMPERATURES 5-10F TOO WARM ALONG COASTAL SECTIONS OF
SOUTHERN CALIFORNIA BETWEEN ROUGHLY IRVINE TO SANTA MARIA. THE NAM
NEAR-SURFACE RELATIVE HUMIDITY FIELDS WERE TOO DRY ALONG THE
SOUTHERN/CENTRAL CALIFORNIA COAST...WEST OF SANTA MARIA...WHERE
SOME FOG WAS OBSERVED.

OTTO