NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1044 AM EDT FRI JUL 22 2011
 
*** 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). ***


...CALIFORNIA/SOUTHWEST/CENTRAL ROCKIES...
THE NAM INITIALIZED 5-20 DEGREES TOO COOL OVER THE SIERRA
NEVADA...MOGOLLON RIM...THE MOJAVE DESERT...SOUTHERN
ARIZONA...MUCH OF SOUTHWEST IDAHO...NEAR EL PASO TEXAS...AND IN
THE TEMPERATURE/ELEVATION GRADIENT IN CENTRAL COLORADO.  THE NAM
HAS 5 DEGREES TOO WARM ACROSS NORTHWEST NEW MEXICO.  

THE NAM POORLY INITIALIZED THE ENTIRE WIND FIELD IN WESTERN
TEXAS...NEW MEXICO...AND NORTHERN MEXICO BY INITIALIZING ONE WIND
CIRCULATION IN WESTERN TEXAS RATHER THAN TWO IN CENTRAL NEW MEXICO
AND ACROSS CENTRAL MEXICO...LEADING TO SIGNIFICANT DIRECTIONAL
ERRORS ACROSS THE WHOLE REGION.  WINDS WERE INITIALIZED 10 KNOTS
TOO LIGHT IN THE SOUTHERN SAN JOAQUIN VALLEY IN CALIFORNIA AND
ACROSS SOUTHWEST IDAHO.  THE NAM WAS ABOUT 80 MILES TOO SLOW WITH
THE POSITION OF A PACIFIC COLD FRONT MOVING ACROSS CENTRAL NEVADA.


...EASTERN THIRD OF THE COUNTRY...
THE NAM HAS 15 DEGREES TOO COLD WITH THE TEMPERATURES IN CENTRAL
LAKE SUPERIOR.  WINDS WERE INITIALIZED 10 KNOTS TOO LIGHT ACROSS
WESTERN OKLAHOMA.  THE NAM DID NOT PROPERLY INITIALIZE A WIND
CIRCULATION IN SOUTHEAST NEBRASKA...LEADING TO DIRECTIONAL ERRORS
IN THAT AREA.  THE OUTFLOW BOUNDARY ACROSS NORTHERN MISSOURI AND
EASTERN IOWA WAS NOT PROPERLY INITIALIZED... LEADING TO
SIGNIFICANT DIRECTIONAL ERRORS THERE.  WINDS WERE MORE SOUTHERLY
THAN THE NAM INITIALIZED ACROSS SOUTHERN MINNESOTA.  THE NAM DID
NOT PICK UP ON THE WIND CIRCULATION ACROSS SOUTHWEST
MICHIGAN...LEADING TO DIRECTIONAL ERRORS THERE AS WELL AS ACROSS
NORTHERN INDIANA.

THE AREA OF MOISTURE ACROSS THE UPPER MIDWEST WAS LOCATED 80 MILES
FARTHER NORTH THAN THE NAM INITIALIZED.  THUNDERSTORMS ARE A BIT
NORTH AND EAST OF WHERE THE NAM INDICATED ACROSS SOUTHERN MICHIGAN
AND SOUTHERN WISCONSIN.  RAINFALL ACROSS MAINE FELL OVER 100 MILES
NORTH OF WHERE THE NAM INDICATED ACROSS MAINE...AND WAS LIGHTER IN
AMOUNTS AND SMALLER IN COVERAGE.  WHILE THE RAIN IN SOUTHEAST
KENTUCKY WAS WELL INDICATED...THE RAINFALL AREA EXTENDED TOO FAR
NORTH INTO NORTHEAST KENTUCKY.  MOST OF THE PRECIPITATION THE NAM
INDICATED ACROSS SOUTHERN LOUISIANA HAS NOT FALLEN THIS
MORNING...WITH THE COVERAGE SEVERELY OVERDONE WEST OF NEW ORLEANS.
 RAINFALL INDICATED BY THE NAM ACROSS CENTRAL FLORIDA HAS NOT
FALLEN.  RAINFALL ACROSS ARKANSAS MATERIALIZED ABOUT 70 MILES
SOUTHWEST OF WHERE THE NAM INDICATED.

ROTH