MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1131 PM EST WED NOV 16 2016 VALID NOV 17/0000 UTC THRU NOV 20/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. DEEP LAYER CYCLONE IN THE EASTERN PACIFIC ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z ECMWF/UKMET COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z GFS ENDS UP TOWARD THE QUICKER SIDE OF THE DETERMINISTIC/ENSEMBLE SPREAD INTO THE PACIFIC NORTHWEST WITH THE APPROACH OF A WEAKENING CLOSED LOW STARTING SAT. THE GFS IS ALSO NOTABLY WEAKER AT THE SURFACE UP TO THE MID LEVELS...MORE SO THAN THE AGREEABLE SREF/GEFS/EC MEANS. THERE IS FAIRLY GOOD AGREEMENT WITH THE TIMING AND STRENGTH OUTSIDE OF THE 00Z GFS...EXCEPT FOR THE SLOWER 12Z CMC. A 00Z NAM...12Z ECWMF/UKMET BLEND APPEARS REASONABLE HERE. SYSTEM MOVING FROM THE PLAINS THROUGH THE GREAT LAKES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/12Z ECMWF COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE MODEL TIMING DIFFERENCES CONTINUE WITH THE GFS ON THE FASTER SIDE OF THE MODELS...WHILE THE ECMWF IS TOWARD THE SLOWER SIDE. RUN TO RUN CONSISTENCY HAS BEEN RELATIVELY GOOD WITHIN EACH MODEL...BUT THE SPREAD BETWEEN THE FASTER GFS AND ECMWF INCREASES INTO SUN MORNING ACROSS THE NORTHEAST. BY SUN..THE 00Z NAM IS UNIQUE WITH ITS STRONG LOW MID-LEVEL HEIGHT CENTER OVER THE NORTHEAST...WHILE THE 12Z CMC IS ON THE FAR EDGE OF THE ENSEMBLE ENVELOPE IN BEING DISPLACED SOUTHWARD. GIVEN THE GFS AND ECMWF HAVE BEEN KNOWN TO HAVE FASTER AND SLOWER BIASES...RESPECTIVELY...REGARDING SYNOPTIC SCALE UPPER TROUGHS LIKE THIS...FEEL COMFORTABLE WITH A PREFERENCE IN THE MIDDLE OF THE GFS AND ECMWF. A BLEND OF THE TWO IS FAVORABLY PLACED WITH RESPECT TO THE LATEST SCATTER ENSEMBLE LOW PLOTS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... OTTO