NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1015 AM EDT WED JUN 20 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 VALLEYS OF CALIFORNIA/DESERT SOUTHWEST...

SURFACE TEMPERATURES VARY 5 TO 10 DEGREES WARMER AND COLDER IN THE
SOUTHWEST DESERTS AND INTERIOR CALIFORNIA RESPECTIVELY. SURFACE
WIND SPEEDS IN BOTH AREAS SEEM INITIALIZED REASONABLY.


...NORTHERN FRONT RANGE OF COLORADO...

THE ONLY INITIALIZATION ERROR APPEARS TO BE WITH THE NAM
PRECIPITATION ACROSS NORTH-EASTERN COLORADO... AS NATIONAL RADAR
DEPICTS NO RAINFALL AND JUST A COLD FRONTAL PASSAGE.


...MIDDLE ATLANTIC/GREAT LAKES AND OHIO/TENNESSEE VALLEYS...

IT APPEARS THE NAM HAS INITIALIZED WELL WITH SURFACE TEMPERATURES
AND WINDS ALONG WITH NO DEPICTION OF ANY PRECIPITATION... AS A
LARGE DOME OF SURFACE HIGH PRESSURE BUILDS ACROSS THE EXTENDED
REGION.


MUSHER