NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1030 AM EDT THU AUG 16 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...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...SERN CA/AZ/NM/WESTERN TX...

NAM INITIALIZED SURFACE TEMPERATURES WERE 5 TO 10 DEGREES TOO COOL
ALONG THE CA/AZ BORDER. ADDITIONALLY...THEN NAM DOES NOT APPEAR TO
HAVE INITIALIZED THE PRECIPITATION ACROSS PORTIONS OF AZ VERY
WELL...AS RADAR INDICATES A WIDER COVERAGE OF PRECIPITATION THAN
WAS SHOWN IN THE FIRST THREE HOURS OF THE NAM FORECAST.


...SNAKE RIVER VALLEY IN IDAHO/NORTHERN WASATCH IN UTAH...

NAM INITIALIZED SURFACE TEMPERATURES WERE 5 TO 8 DEGREES TOO COOL
IN THE VICINITY OF SALT LAKE CITY.


...WASHINGTON/OREGON...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...COLORADO...

NAM INITIALIZED SURFACE TEMPERATURES WERE 5 TO 7 DEGREES TOO COOL
IN AREAS OF NORTH CENTRAL COLORADO...NORTH OF DENVER...AS WELL AS
IN PORTIONS OF THE COLORADO ROCKIES.


...TEXAS/OKLAHOMA...
NAM INITIALIZED 10-METER WINDS WERE AS MUCH AS 10 KT TOO LIGHT
ACROSS PORTIONS OF NORTH CENTRAL/NORTHEASTERN TEXAS...IN THE
VICINITY OF DALLAS-FORT WORTH.


...NORTHEAST U.S...
INITIALIZED 10-METER WIND DIRECTIONS WERE 3O TO 45 DEGREES OFF ON
THE EASTERN SHORE OF LAKE ONTARIO IN NEW YORK. OBSERVED WIND FLOW
AROUND THE LAKE APPEARED TO BE CONVERGENT ON THE LAKE...WITH FLOW
ON THE SOUTH SIDE OF THE LIKE MORE SOUTHERLY THAN INITIALIZED BY
THE NAM.


...MIDWEST TO THE MID-ATLANTIC AND SOUTHEASTERN STATES...

THE NAM DID NOT INITIALIZE THE THUNDERSTORM COMPLEX ACROSS THE
MIDWEST/GREAT LAKES AREA THIS MORNING WELL AT ALL. PRECIPITATION
AMOUNTS FORECAST BY THE NAM DURING THE FIRST THREE HOURS OF THE
MODEL RUN WERE SIGNIFICANTLY UNDERDONE OR EVEN NON-EXISTENT IN THE
VICINITY OF THIS THUNDERSTORM COMPLEX.

RYAN