NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1036 AM EDT WED AUG 01 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/SOUTHERN NEVADA/SOUTHERN ARIZONA...
THE NAM INITIALIZES SURFACE WINDS PERHAPS 5KTS OR SO LIGHTER THAN
THE ACTUAL WINDS ACROSS PARTS OF SRN CA. THE NAM IS MUCH HEAVIER
WITH PRECIPITATION AMOUNTS OVER CENTRAL AZ AND THE DESERT OF SRN
CA THAN OBSERVED RADAR ACTIVITY.

...COLORADO...
THE NAM SEEMS INITIALIZED REASONABLY WELL HERE.


...SOUTHERN PLAINS/MID TO LOWER MISSISSIPPI VALLEY/OHIO TO
TENNESSEE VALLEY/APPALACHIANS...
THE NAM DID NOT INITIALIZE THE THUNDERSTORM CLUSTER WEST OF THE
KANSAS CITY METRO AREA WELL ALONG WITH THE LIGHTER ACTIVITY OVER
ARKANSAS... NAM INDICATES HEAVIER PRECIPITATION OVER MISSOURI
INSTEAD.


MUSHER