MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1230 AM EDT THU OCT 15 2015 VALID OCT 15/0000 UTC THRU OCT 18/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...UPPER LOW CROSSING THE SOUTHWEST... PREFERENCE: BLEND OF THE 00Z NAM/00Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE THERE IS REASONABLY GOOD AGREEMENT AT THIS POINT AMONG THE MODELS IN TAKING THIS SYSTEM GRADUALLY INLAND ACROSS CA THROUGH FRI AND THEN EAST ACROSS THE FOUR CORNERS REGION SAT WHILE GRADUALLY DAMPENING OUT. HOWEVER...THE 12Z UKMET AND 12Z CMC ARE LIKELY WEAKENING THE SYSTEM A LITTLE TOO QUICKLY. THE 00Z NAM/00Z GFS AND 12Z ECMWF ALL HANG ON TO A SLIGHTLY BETTER DEFINED TROUGH AS IT CROSSES INTO THE FOUR CORNERS REGION BEFORE DAMPENING OUT. A BLEND OF THE 00Z NAM/00Z GFS AND 12Z ECMWF WILL BE PREFERRED. ...SHORTWAVE TROUGH INFLUENCING THE WEST COAST FRI NIGHT/SAT... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE THE EVOLUTION OF THE TROUGH IS AFFECTED BY THE FLOW ACROSS THE GULF OF ALASKA...WITH THE 12Z A BIT SLOWER AND DEEPER THAN THE MULTI-MODEL CONSENSUS AS THE ENERGY ARRIVES ALONG THE WEST COAST ON SAT. THE 00Z NAM/00Z GFS/12Z ECMWF AND 12Z UKMET ARE ALL RATHER WELL CLUSTERED...WITH THE BEST CLUSTERING FAVORING A 00Z GFS/12Z ECMWF BLEND. THUS A NON-CMC CONSENSUS LED BY A BLEND OF THE 00Z GFS AND 12Z ECMWF WILL BE PREFERRED. ...LOW PRESSURE CROSSING THE GREAT LAKES/NORTHEAST THU-FRI... PREFERENCE: NON-NAM CONSENSUS CONFIDENCE: ABOVE AVERAGE THE 00Z NAM LIES NEAR THE SLOWER AND SOMEWHAT STRONGER EDGE OF THE GUIDANCE AND THEREFORE IS DISCOUNTED IN FAVOR OF THE OTHERWISE WELL CLUSTERED GLOBAL MODEL CONSENSUS. A NON-NAM CONSENSUS WILL BE PREFERRED AS A RESULT. ...SECOND LOW PRESSURE WAVE CROSSING NORTHERN NEW ENGLAND ON SAT... PREFERENCE: NON-ECMWF CONSENSUS CONFIDENCE: AVERAGE THE 12Z ECMWF APPEARS TO BE A LITTLE TOO FAR SOUTH WITH ITS WAVE TRACK...AND IS EVEN A BIT SOUTH OF THE 12Z ECENS MEAN. THE 00Z GFS/12Z UKMET AND 12Z CMC ARE ALL CLUSTERED A BIT FARTHER NORTH. THE 00Z NAM IS LIKELY A LITTLE TOO WEAK/ILL-DEFINED WITH THIS SECOND WAVE BUT DOES TEND TO OTHERWISE CLUSTER WELL WITH THE NON-ECMWF SOLUTIONS. BASED ON THE LATEST CLUSTERING AND TRENDS...A NON-ECMWF CONSENSUS WILL BE PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON