MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1254 PM EDT FRI MAY 13 2016 VALID MAY 13/1200 UTC THRU MAY 17/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NCEP MODEL EVALUATION AND PRELIMINARY PREFERENCES/CONFIDENCE GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. ...SHORTWAVE TROUGH CROSSING THE OH VALLEY/NORTHEAST FRI BECOMING A CLOSED MID LEVEL LOW SAT... PREFERENCE: 12Z GFS/00Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z MODELS WERE ALL CLUSTERED FAIRLY CLOSELY TO EACH OTHER AS A SHORTWAVE CROSSES THE OH VALLEY AND MAKES ITS WAY TOWARDS THE NORTHEAST U.S.. HOWEVER...AS THE MID LEVEL SYSTEM CLOSES OFF...THE 12Z NAM SLOWS OVER NORTHERN NEW ENGLAND/QUEBEC SAT AND CONTINUES TO DEFINE THE WESTERN MOST SOLN. THE 12Z GFS HAD REASONABLY GOOD RUN TO RUN CONTINUITY...SO IT TOO BECOMES A LITTLE SLOW WITH THE MID LEVEL SYSTEM. IT IS CLOSE ENOUGH THAT A COMPROMISE POSITION BETWEEN THE NEW GFS AND THE 00Z ECMWF SHOULD PRODUCE AND ACCEPTABLE SOLN ON SATURDAY. ...SURFACE LOW MOVING ACROSS OH VALLEY FRI/SAT THEN INTO NEW ENGLAND SUN... PREFERENCE: 00Z NAM/00Z CMC/00Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z NCEP MODELS WERE CLOSE TO THE CONSENSUS WITH THE SURFACE LOW AS IT TRACKS ACROSS THE OH VALLEY INTO NEW ENGLAND...AND BY SUN IT IS CLOSE TO THE CONSISTENT 12Z ECMWF ACROSS NORTHERN ME BY SUN EVENING. ...COLD FRONT CROSSING THE GREAT LAKES/MS AND OH VALLEY FRI/FRI NIGHT... PREFERENCE: 12Z NAM/00Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z NAM WAS CLOSE TO THE CONSENSUS WITH THE FRONTAL TIMING AS IT APPROACHES THE OH VALLEY LATER TONIGHT...WHILE THE 12Z GFS CONTINUED TO BE FASTER WITH OTHER MODELS WITH THE FRONT. THE 00Z ECMWF HAS BEEN THE MOST CONSISTENT WITH THE FRONTAL TIMING...SO A BLEND OF THE 12Z NAM/00Z ECMWF IS PREFERRED. ...SHORT WAVE CROSSING TX SUN... PREFERENCE: 00Z ECMWF/00Z CMC CONFIDENCE: AVERAGE THE 12Z NAM AND GFS ARE CLOSE WITH THE SHORT WAVE AS IT TRACKS FROM THE NORTHERN BAJA PENINSULA SAT BEFORE REACHING TX ON SUN. THE 12Z GFS CONTINUES TO OFFER A FLATTER SOLN...12Z NAM. THE 00Z ECMWF HAS BEEN THE MOST CONSISTENT WITH THE SHORT WAVE TIMING...AND THE 00Z CMC HAS COME INTO LINE WITH THE 00Z ECMWF SOLUTION IN PLACEMENT AND STRENGTH. BECAUSE OF THIS...THE 00Z CMC AND 00Z ECMWF WERE PREFERRED. ...SHORTWAVE TROUGH REACHING THE WEST COAST SAT... PREFERENCE: GENERAL MODE BLEND CONFIDENCE: ABOVE AVERAGE GIVEN GOOD CLUSTERING OF OPERATIONAL MODELS AND THEIR ENSEMBLES INTO SUNDAY...A GENERAL MODEL BLEND IS PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN