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NAM Air Quality Diagnostic Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1438Z Aug 27, 2012)
 
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1038 AM EDT MON AUG 27 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). ***


...GREAT LAKES/MIDWEST/MID-ATLANTIC STATES...
THE NAM WAS 5F TOO COLD ACROSS SOUTHWEST VIRGINIA AND CLOSE TO 5F
TOO WARM ACROSS CENTRAL WEST VIRGINIA AND NORTHERN WISCONSIN.  THE
NAM WAS 5-10 KNOTS TOO WEAK WITH THE WINDS IN ILLINOIS.  THE NAM
IS AT LEAST 100 MILES TOO FAR WEST WITH THE PRECIPITATION
OCCURRING OVER OHIO THIS MORNING.  THE NAM'S PRECIPITATION WAS
MUCH TOO EXTENSIVE WITH THE THUNDERSTORM AREA OVER NEW JERSEY AND
ITS INTENSITY WAS TOO LIGHT.


...MID-SOUTH/SOUTHEAST...
...SOUTHERN PLAINS...
NO NAM INITIALIZATION ISSUES WERE NOTED.


...INTERMOUNTAIN WEST...
THE NAM WAS 5-10F TOO WARM ACROSS PORTIONS OF CENTRAL AND NORTHERN
NEW MEXICO, SOUTHERN COLORADO, SOUTHERN UTAH, AND NORTHERN
ARIZONA.  THE NAM WAS 5-10F TOO COLD NEAR SUPERIOR COLORADO,
EASTERN UTAH, AND SOUTHWEST IDAHO.  THE NAM WINDS WERE NOT
NORTHERLY ENOUGH SOUTH OF DENVER COLORADO DUE TO ITS POOR
REPRESENTATION OF THE SOUTHEASTERN COLORADO LOW PRESSURE SYSTEM. 
WINDS WERE MORE EASTERLY THAN THE NAM DEPICTED ACROSS WESTERN
IDAHO.  NAM WINDS WERE 5-10 KNOTS TOO WEAK ACROSS PORTIONS OF
SOUTHERN AND EASTERN WASHINGTON.  THE NAM HAS SIGNIFICANTLY
OVERESTIMATED THE RAINFALL IT EXPECTED NEAR YELLOWSTONE NATIONAL
PARK.


...ARIZONA/SOUTHERN NEVADA/CALIFORNIA...
THE NAM WAS 5F TOO COOL ACROSS SOUTHERN ARIZONA, SOUTHERN NEVADA,
AND PORTIONS OF SOUTHERN AND CENTRAL CALIFORNIA.  THE NAM HAD A
POOR REPRESENTATION OF THE CYCLONIC CIRCULATION ACROSS SOUTHEAST
ARIZONA...WHICH LED TO DIRECTIONAL ERRORS ACROSS MUCH OF SOUTHERN
ARIZONA.  THE NAM HAD A POOR REPRESENTATION OF THE WIND FIELD IN
THE VICINITY OF THE CYCLONIC CIRCULATION NEAR SACRAMENTO
CALIFORNIA.


ROTH