MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER CAMP SPRINGS MD
137 PM EDT THU AUG 16 2012

VALID AUG 16/1200 UTC THRU AUG 20/0000 UTC


...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR INGEST...

FINAL 12Z MODEL EVALUATION

ANY INITIALIZATION ERRORS IN THE NAM/GFS DO NOT APPEAR TO
SIGNIFICANTLY IMPACT THEIR FORECASTS...

...LONGWAVE AND FRONT MIGRATING THROUGH THE MIDWEST AND
NORTHEAST...DAYS 1-3

PREFERENCE: 12Z GFS-CANADIAN/00Z ECMWF BLEND
CONFIDENCE: AVERAGE

THE 12Z GFS AND 00Z ECMWF WERE TWO GOOD STARTING POINTS THIS
MORNING THROUGH DAY 2. WITH THE 12Z CANADIAN AND UKMET IN...THE
12Z GFS CARRIES A SLIGHTLY FASTER/DEEPER SYSTEM ALONG 80W
LONGITUDE BY EARLY DAY 3 VS THE OTHER 12Z SOLUTIONS IN HANDLING
THE FRONTAL PROGRESSION THROUGH THE MIDWEST AND OHIO VALLEY DAY 1
THE MODELS WERE ROCK SOLID. THEN WITH THE SECONDARY IMPULSE
TRACKING SOUTHEASTWARD FROM SOUTHERN CANADA INTO THE MISSOURI
VALLEY BETWEEN DAY 2-3...THE CANADIAN AND GFS WOULD BE THE QUICKER
SOLUTIONS ACROSS THE MID MISSOURI VALLEY. THE FINER DETAILS HAVE
YET TO BE DETERMINED...BUT THE BLENDED MASS FIELDS OF THE SLIGHTLY
FASTER 12Z GFS AND THE SLOWER 00Z ECMWF IS A GOOD PLACE TO START
THROUGH DAY.  DIFFERENCES CROP UP ALONG THE SOUTHERN END OF THE
FRONT EARLY ON IN THE LATE DAY 1 PERIOD...SO BLENDING THE TWO WILL
MITIGATE THESE DIFFERENCES. FOR DAYS 2-3...SOMETHING CLOSER TO THE
00Z ECMWF/12Z CANADIAN SEEMS TO HANDLE THE FASTER GFS SOLUTION BY
THE END OF DAY 3.

...NEGATIVE TILT TROUGH MOVING ACROSS NEW ENGLAND...DAY 1

PREFERENCE: 12Z MODEL CONSENSUS AND 00Z ECMWF BLEND
CONFIDENCE: ABOVE AVERAGE

THE 12Z GUIDANCE OVERALL AGREES WITH THE MASS FIELD FORECAST FOR A
TRACK THROUGH THE GULF OF MAINE DURING THE DAY 1 PERIOD. THE
DIFFERENCES ARE TIED TO THE FINER DETAILS AND QPFS. HOWEVER...NOT
ENOUGH OF A DIFFERENCE FOR WAVER FROM THE SOLID MODEL CONSENSUS.

...MODEL TREND GRAPHICS AT
WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...
...500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...

VOJTESAK