NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1025 AM EDT TUE AUG 14 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 INCLUDING THE BAY AREA OVER TO
RENO NEVADA...

SURFACE TEMPERATURES INITIALIZED AROUND 5 DEGREES TOO COOL AT A
FEW DESERT LOCATIONS FROM PALM SPRINGS EASTWARD TO THE BORDERS
WITH ARIZONA AND SOUTHERN NEVADA.


...DESERT AREAS OF ARIZONA/SOUTHERN NEVADA/SOUTHERN CALIFORNIA...

SURFACE TEMPERATURES INITIALIZED AROUND 5 DEGREES TOO COOL AT A
FEW DESERT LOCATIONS NEAR PHOENIX AND LAS VEGAS...WESTWARD INTO
CALIFORNIA.


...INTERSTATE 84 CORRIDOR SURROUNDING BOISE IDAHO...

SURFACE TEMPERATURES INITIALIZED 5 TO 10 DEGREES TOO COOL IN THE
LOWER SNAKE RIVER VALLEY AROUND BOISE...AND 5 TO 15 DEGREES TOO
WARM ON SOME OF THE MOUNTAIN SLOPES SURROUNDING THE VALLEY.


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

SURFACE TEMPERATURES INITIALIZED AROUND 5 DEGREES TOO COOL IN THIS
AREA.


...COLORADO...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...OKLAHOMA/TEXAS INTO THE ARKLATEX...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...METROPOLITAN AREAS IN THE CENTRAL/EASTERN U.S...

AN ORGANIZED AREA OF RAIN OVER THE MID ATLANTIC REGION APPROACHING
NEW JERSEY/NEW YORK CITY...IS PLACED TOO FAR WEST IN THE FIRST FEW
HOURS OF THE NAM FORECAST. THIS RESULTS IN THE NAM INITIALLY
SHOWING LIGHT SOUTHEAST WINDS OVER NEW JERSEY...WHERE OBSERVED
WINDS HAD BECOME NEARLY CALM.

THE NAM ALSO FAILS TO DEPICT AN ORGANIZED AREA OF RAIN PROGRESSING
THROUGH NORTHERN AND CENTRAL GEORGIA. ASSOCIATED OUTFLOW HAD AT
LEAST TEMPORARILY VEERED WINDS TO SOUTHWEST OR WEST...COMPARED TO
SOUTHERLY/SOUTHWESTERLY WINDS IN THE MODEL...ALTHOUGH THERE WAS
NOT APPRECIABLE CHANGE IN SPEED. ALSO AS A RESULT OF MISSING THE
RAIN AREA...THE NAM INITIALIZED TOO DRY IN THE BOUNDARY LAYER OVER
NORTHERN AND CENTRAL GEORGIA.

BURKE/RYAN