NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1023 AM EDT MON JUL 04 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). ***

...MID-ATLANTIC STATES/NORTHEAST/OHIO VALLEY/GREAT
LAKES/MIDWEST...
THE NAM WAS 5 DEGREES TOO COOL WITH ITS TEMPERATURE FIELD IN
SOUTHERN IOWA.  ITS WIND PATTERN IS MUCH TOO WESTERLY ACROSS
SOUTHERN NEW ENGLAND AND SOUTHERN VIRGINIA /WHERE WINDS ARE
SOUTH/.  THE NAM WAS AT LEAST 100 MILES TOO FAR NORTHWEST WITH THE
RAIN AREA IS DEPICTED NEAR THE LOWER OHIO RIVER.

...SOUTHEAST/GULF COAST/SOUTHERN PLAINS...
THE NAM INITIALIZED THE TEMPERATURES 5 DEGREES TOO COOL IN FAR
SOUTHEAST TENNESSEE.  ITS WINDS ARE TOO EASTERLY ACROSS SOUTHWEST
OKLAHOMA...WHERE THE WINDS ARE MORE NORTHERLY...AND TOO SOUTHERLY
ACROSS SOUTHERN TEXAS WHERE THE WINDS ARE OUT OF THE EAST.  THERE
IS NO RAIN FALLING WITHIN THE RAIN AREA DEPICTED BY THE NAM ACROSS
THE SOUTHEAST...WITH THE SIGNIFICANT THUNDERSTORMS IN SOUTHEAST
ALABAMA AND SOUTHWEST GEORGIA JUST OUTSIDE THE SOUTHEAST EDGE OF
ITS PREDICTED RAIN AREA...WHICH IS ALSO MUCH SMALLER IN AREAL
EXTENT.

...SOUTHWEST/CALIFORNIA...
THE NAM INITIALIZATION SHOWS TEMPERATURES 5 TO 15 DEGREES F COOLER
THAN OBSERVED ACROSS THE MOJAVE DESERT...NEAR NEVADA/CALIFORNIA
BORDER...PORTIONS OF THE NORTHERN CALIFORNIA COAST...AND ACROSS
THE SISKIYOU MOUNTAINS IN NORTHERN CALIFORNIA.  THE RAINFALL
ACROSS THE SOUTHWEST IS AT LEAST 100 MILES FARTHER NORTH THAN THE
NAMS DEPICTION ACROSS THE MOJAVE DESERT/LOWER COLORADO RIVER
VALLEY. 

ROTH