NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1030 AM EDT FRI AUG 24 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). ***

...MID ATLANTIC/NORTHEAST...

NO SIGNIFICANT INITIALIZATION ERRORS.


...GREAT LAKES/OHIO VALLEY...

NO SIGNIFICANT INITIALIZATION ERRORS.


...MIDWEST/SOUTHERN PLAINS...

THE NAM APPEARED FAIRLY WELL INITIALIZED WITH RESPECT TO ONGOING
RAIN/THUNDERSTORMS IN OKLAHOMA AND KANSAS...NEARING KANSAS CITY.
THE NAM MAY BE INDICATING TOO MUCH RAIN...HOWEVER...IN SOUTHWEST
OKLAHOMA...WHERE RADAR TRENDS SHOWED RAIN DISSIPATING. WINDS WERE
ALSO OBSERVED TO BE MORE DIVERGENT BENEATH THE RAIN IN NORTHEAST
KANSAS. THE RESULT IS THE NAM INDICATING SOUTHEAST WINDS OVER
KANSAS CITY...WHERE OBSERVATIONS SHOWED AT LEAST A TEMPORARY
SWITCH TO LIGHT WEST WINDS.

...SOUTHEAST...

NO SIGNIFICANT INITIALIZATION ERRORS.


...SOUTH TEXAS...

NO SIGNIFICANT INITIALIZATION ERRORS.


...INTERMOUNTAIN POPULATION CENTERS INCLUDING BOISE...SALT
LAKE...AND PARTS OF COLORADO...

NO SIGNIFICANT INITIALIZATION ERRORS.


...ARIZONA/SOUTHERN NEVADA TO SOUTHERN CALIFORNIA...

THE NAM INITIALIZED TEMPERATURE 7 TO 12 DEGREES TOO COOL IN THE
FOOTHILLS NEAR PALM SPRINGS AND TWENTYNINE PALMS...AND AROUND 7
DEGREES TOO COOL NEAR LAS VEGAS. A FEW RAIN SHOWERS WERE OCCURRING
JUST SOUTH AND SOUTHEAST OF PHOENIX. THE NAM MIS-PLACES THESE
SHOWERS NORTH OF PHOENIX DURING THE EARLY HOURS OF ITS FORECAST.

...INTERIOR VALLEYS OF CENTRAL AND NORTHERN CALIFORNIA OVER TO
RENO NEVADA...

THE NAM INITIALIZED AROUND 10 DEGREES TOO WARM IN SOME OF THE
MOUNTAIN VALLEYS WEST OF RENO...SUCH AS NEAR LAKE TAHOE.

BURKE