NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1028 AM EDT THU JUN 21 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/DESERT SOUTHWEST...
THE NAM IS 5-10F TOO COLD IN POCKETS ACROSS THE MOJAVE DESERT AND
CENTRAL VALLEY OF CALIFORNIA AND 10F TOO WARM ACROSS SOUTHWEST
CALIFORNIA AND PORTIONS OF THE SIERRA NEVADA RANGE.  WINDS WERE
MORE SOUTHERLY THAN INDICATED ON THE NAM ACROSS ARIZONA AND ABOUT
5 KNOTS TOO LIGHT ACROSS THE CENTRAL VALLEY OF CALIFORNIA.


...COLORADO/UTAH/IDAHO...
POCKETS OF CENTRAL COLORADO AND WEST-CENTRAL IDAHO ARE 5-10F
COLDER THAN THE NAM.  WINDS ARE 10 KNOTS HIGHER THAN INDICATED ON
THE NAM ACROSS CENTRAL COLORADO AND SOUTHWEST IDAHO.


...SOUTHERN PLAINS...
WINDS WERE MORE WESTERLY THAN THE NAM INDICATED ACROSS PORTIONS OF
NORTHEAST OKLAHOMA...DUE TO ONGOING CONVECTION. THE NAM HAS
UNDERPLAYED BOTH THE COVERAGE AND INTENSITY OF RAINFALL ACROSS
OKLAHOMA...THE OZARKS...AND SOUTHERN KANSAS.


...NORTHEAST/MID-ATLANTIC/MID-SOUTH/OHIO AND TENNESSEE VALLEYS...
THE NAM IS 5F TOO COOL ACROSS NORTHERN NEW HAMPSHIRE AND 5F TOO
WARM ACROSS CENTRAL MAINE.  THE PRECIPITATION THE NAM INDICATED
ACROSS EASTERN TENNESSEE NEVER MATERIALIZED.


ROTH