MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1257 PM EDT WED SEP 02 2015 VALID SEP 02/1200 UTC THRU SEP 06/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION UPPER TROUGH FORMING ACROSS THE PACIFIC NORTHWEST... PREFERENCE: MODEL CONSENSUS CONFIDENCE: AVERAGE THE GFS BACKED OFF ON THE DEPTH OF THE TROF AND CLOSED LOW BY 12Z SAT WHILE THE 12Z NAM IS STRONGER/DEEPER THAN IT WAS ON ITS 02/00Z RUN. THE 02/00Z ECMWF WAS SLIGHTLY WEAKER AND NORTH BY OF THE MODEL CONSENSUS AT THIS POINT. WILL SUGGEST THAT A MODEL CONSENSUS SHIFTED TOWARDS THE 12Z GFS IS THE BEST APPROACH AT THIS POINT. SHORTWAVE TROUGH ACROSS THE UPPER MIDWEST... PREFERENCE: BEFORE 12Z THU...EQUAL BLEND GFS/ECMWF DAY 1 LEANING GFS DAY 2/3 CONFIDENCE: BEFORE 12Z THU...BELOW AVERAGE THE 12Z NCEP RUNS STILL POINT TO A CONSENSUS EARLY IN THE FORECAST PERIOD WITH A SHIFT TO THE GFS PRIMARILY IN THE DAY 2/3 CYCLE. THE HI-RES SOLUTIONS LOSE THEIR SOUTHWARD QPF EMPHASIS BY TONIGHT AND SHIFT CONVECTION NORTHWARD ALONG THE STATIONARY BOUNDARY. THE GLOBAL MODELS TENDED TO PUT MORE EMPAHSIS ON A SOUTHERLY SOLN...PERHAPS DUE TO THEIR CONVECTIVE PARAMETERIZATIONS THAT ALLOW FOR EASIER TRIGGERING. THE CURRENT PREFERENCE FOR MASS FIELDS REMAINS TOWARDS A MORE SOUTHWARD ORIENTED SOLUTIONS. SHORTWAVE TROUGH MOVING FROM THE SOUTHWEST TO THE PLAINS THU-FRI... PREFERENCE: NAM OR GFS OR ECMWF CONFIDENCE: AVERAGE THE NAM AND GFS HAVE TRENDED WESTWARD WITH ITS TRACK AND SHOW FAIRLY GOOD AGREEMENT WITH EACH OTHER THROUGH 84 HRS...WITH SUPPORT FROM THE 00Z ECMWF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN