NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1016 AM EDT MON JUL 11 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). ***


...NORTHEAST/EASTERN GREAT LAKES/MID ATLANTIC/APPALACHIANS...

SOME LOCATIONS OVER WEST-CENTRAL NEW YORK STATE ARE OBSERVING
SURFACE WINDS FROM THE SOUTHEAST IN CONTRAST TO THE NAM ANALYSIS
THAT SHOWS WINDS FROM THE SOUTH-SOUTHWEST.


...TENNESSEE VALLEY/SOUTHEAST...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...MID-UPPER MISSISSIPPI VALLEY TO CENTRAL GREAT LAKES/OHIO
VALLEY...

THE NAM DOES NOT PROPERLY RESOLVE THE CONVECTIVE SYSTEMS OBSERVED
OVER LOWER MICHIGAN INTO LAKE MICHIGAN AND WISCONSIN/ILLINOIS INTO
EASTERN IOWA.  ALONG THE EASTERN SHORE OF LAKE MICHIGAN... THE NAM
ANALYZES SURFACE WINDS FROM THE SOUTH AT 10 KTS WHILE OBSERVATIONS
REPORT NEARLY CALM WINDS NEAR THE SOUTHERN SHORE AND FROM THE
NORTHWEST AT 25 KTS A LITTLE FARTHER NORTH NEAR THE SOUTH-CENTRAL
SHORE.  IN ADDITION NEAR THE IOWA/ILLINOIS BORDER SURFACE WINDS
ARE FROM THE WEST OR NORTHWEST AT 10 TO 20 KTS VERSUS THE NAM
ANALYSIS THAT HAS LIGHT WINDS FROM THE SOUTH.


...SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY...

NO SIGNIFICANT INITIALIZATION ERRORS WERE NOTED.


...SOUTHWEST/CALIFORNIA...

OBSERVED SURFACE TEMPERATURES IN THE SACRAMENTO VALLEY ARE UP TO 5
TO 10 DEGREES F WARMER THAN INDICATED BY THE 12Z NAM ANALYSIS. 
FURTHER TEMPERATURE ERRORS ARE NOTED ACROSS INTERIOR SOUTHERN
CALIFORNIA AND EXTREME SOUTHERN NEVADA WITH READINGS AS HIGH AS 10
TO 15 DEGREES F WARMER THAN THE NAM INITIALIZATION. 

RAUSCH