NAM AIR QUALITY DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1019 AM EDT FRI JUN 08 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). ***


...SOUTHERN CALIFORNIA AND DESERT SOUTHWEST...
12Z NAM INITIALIZED AT LEAST 5F TOO LOW WITH LOCAL 2-METER TEMPS
ACROSS SOUTHEASTERN CALIFORNIA AND SOUTHWEST ARIZONA. BOUNDARY
LAYER WINDS LOOKED GOOD.

...SOUTHERN INDIANA...CUMBERLAND RIVER BASIN OF KENTUCKY AND
TENNESSEE...
12Z NAM DID A DECENT JOB WITH THE ITS 2-METER TEMPS AND WIND
INITIALIZATIONS.

...EAST TEXAS...
12Z NAM SHOWED NO SIGNIFICANT ERROR WITH THE ITS 2-METER
TEMPS...BOUNDARY-LAYER WINDS AND MOISTURE FIELDS...INCLUDING
PROGGED QPFS OVER THIS REGION.

...NORTHERN INDIANA/ILLINOIS AND CENTRAL OHIO...
12Z NAM MATCHED UP WELL AT INITIALIZATION WITH THE ITS 2-METER
TEMPS AND BOUNDARY-LAYER WIND FIELDS. HOWEVER...ITS UPSTREAM
PRECIPITATION FORECAST ACROSS CENTRAL WISCONSIN LOOKED TO BE IN
ERROR...IE NOT CAPTURED PER RADAR.

VOJTESAK