NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1040 AM EDT THU JUL 12 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). ***


DUE TO TECHNICAL ISSUES... A MORE GENERIC STATEMENT WILL BE ISSUED
FOR POOR AIR QUALITY ACROSS THE COUNTRY.

TWO LARGE SCALE UPPER RIDGES... ONE BASED ALONG THE EASTERN
SEABOARD AND ANOTHER OVER THE ROCKIES COULD FAVOR POOR AIR
QUALITY... AS STRONG HEATING AND POOR AIRFLOW WILL BE ROUTINE
HERE. SOME OF THE MAJOR MARKETS THAT COULD SEE POOR CONDITIONS
INCLUDE BOSTON/NEW YORK CITY DOWN TO ATLANTA/BIRMINGHAM IN THE
EAST AND DENVER/SALT LAKE CITY TO SOUTHERN CALIFORNIA IN THE WEST.
IN THESE AREAS... THE 12Z NAM SEEMS REASONABLY INITIALIZED WELL
WITH MINOR ERRORS.

MUSHER