MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1215 PM EDT MON SEP 14 2015 VALID SEP 14/1200 UTC THRU SEP 18/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. CYCLONE NEAR THE CENTRAL US/CANADIAN BORDER THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/ECMWF/CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE NAM IS SLOW/DEEP/SOUTHWEST WITH THIS SYSTEM -- ITS USUAL BIAS -- WHILE THE UKMET A FAST/NORTH OUTLIER -- ITS USUAL BIAS. A COMPROMISE OF THE 12Z GFS/00Z ECMWF/00Z CANADIAN FITS THE 12Z ECMWF/18Z GEFS MEANS BEST WITH ABOVE AVERAGE CONFIDENCE. CYCLONE OFFSHORE THE NORTHWEST WEDNESDAY POSSIBLE REGENERATION OF GRACE IN THE GULF OF MEXICO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE IN BOTH CASES, THE NAM WAS A STRONG NORTH TO NORTHWEST OUTLIER -- ITS USUAL BIAS. A COMPROMISE OF THE 12Z GFS/00Z ECMWF/00Z CANADIAN/00Z UKMET APPEARS BEST HERE WITH ABOVE AVERAGE CONFIDENCE. CYCLONE MOVING ACROSS THE DAKOTAS TUESDAY SYSTEM LIFTING AWAY FROM NEW ENGLAND TODAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE FEATURES. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH