NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1029 AM EDT MON JUN 11 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). ***


...CALIFORNIA AND DESERT SOUTHWEST...

THE NAM HAS INITIALIZED NEAR-SURFACE TEMPERATURES 5 TO 10 DEGREES
F LOWER THAN OBSERVED OVER PORTIONS OF SOUTHEASTERN CALIFORNIA AND
SOUTH-CENTRAL ARIZONA.


...CENTRAL ROCKIES/HIGH PLAINS...

THE NAM DISPLAYS NO SIGNIFICANT INITIALIZATION ERRORS OVER THIS
REGION.


...EASTERN AND SOUTH-CENTRAL PLAINS...

BASED ON SATELLITE..RADAR..SURFACE OBSERVATIONS..AND FIRST 3-HOUR
QPF FORECAST THE NAM DOES NOT APPEAR TO HAVE AN ACCURATE DEPICTION
OF THE CONVECTIVE SYSTEM OBSERVED OVER EXTREME EASTERN KANSAS INTO
MISSOURI.


...GREAT LAKES/OHIO VALLEY INTO THE MISSISSIPPI VALLEY...

SURFACE OBSERVATIONS OVER NORTHERN ILLINOIS/SOUTHERN WISCONSIN
SHOW LOCAL AREAS EXPERIENCING WINDS FROM THE EAST OR WEST IN
CONTRAST TO THE NAM ANALYSIS THAT HAS BROAD SOUTHERLY FLOW OVER
THE REGION.  RADAR THUS FAR INDICATES THAT THE NAM MAY BE OVERDONE
WITH ITS FIRST 3-HOUR FORECAST OF LIGHT RAINFALL OVER MUCH OF
INDIANA INTO THE WESTERN HALF OF KENTUCKY.


...NORTHEAST AND MID ATLANTIC...
...FLORIDA PENINSULA AND SOUTHEAST GEORGIA...

THE NAM HAS A REASONABLE INITIALIZATION OVER THESE AREAS.


RAUSCH