NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1008 AM EDT FRI JUL 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). ***


...COLORADO FRONT RANGE...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED WITH THE NAM IN
THIS REGION.


...NORTHERN WASATCH FRONT OF UTAH...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED WITH THE NAM IN
THIS REGION.


...INTERIOR VALLEYS OF CALIFORNIA...
...LOWER COLORADO VALLEY...

THE NAM INITIALIZED SURFACE TEMPERATURES ARE 5 TO 10 DEGREES TOO
COOL NEAR THE MOUNTAINS IN THESE REGIONS.


...SOUTHERN ARIZONA...

THE NAM INITIALIZED SURFACE TEMPERATURES ARE 5 TO 8 DEGREES TOO
COOL...PARTICULARLY IN CLOSE PROXIMITY TO THE MOUNTAINS. ISOLATED
TO SCATTERED SHOWERS ACROSS THE HIGHER TERRAIN THIS MORNING DO NOT
APPEAR TO BE WELL-DEPICTED BY THE NAM.


...MIDWEST...

SURFACE WINDS IN NORTHERN OHIO ON THE SOUTH SIDE OF LAKE ERIE WERE
OBSERVED TO BE MORE NORTHERLY THAN INITIALIZED BY THE NAM. THE
DIRECTIONAL ERROR WAS AS MUCH AS 30 DEGREES MORE NORTHERLY THAN
THE NAM INITIALIZATION IN SOME AREAS.


...SOUTHERN STATES...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED WITH THE NAM IN
THIS REGION.


RYAN