MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 235 PM EDT SUN OCT 09 2016 VALID OCT 09/1200 UTC THRU OCT 13/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION INCLUDING THE NAM/GFS/UKMET/CMC/ECMWF AND FINAL MODEL PREFERENCES ...POST-TROPICAL CYCLONE MATTHEW... PREFERENCE: NATIONAL HURRICANE CENTER FORECAST POST-TROPICAL CYCLONE MATTHEW IS FORECAST BY THE NATIONAL HURRICANE CENTER TO CONTINUE MOVING EAST-NORTHEASTWARD INTO THE OPEN WATERS OF THE ATLANTIC OCEAN. LINGERING RAIN AND WIND ACROSS PORTIONS OF THE MID-ATLANTIC AND NORTHEAST WILL COME TO AND END TONIGHT. THE 12Z RUNS OF THE NAM AND GFS BOTH PULL THE SYSTEM FARTHER NORTH RELATIVE TO PREVIOUS RUNS. THE LATEST RUNS OF THE UKMET, CMC, AND ECMWF ALSO PULL THE LOW FARTHER NORTH. THE OFFICIAL FORECAST TRACK OF THE NHC IS CLOSELY RESEMBLED BY A BLEND OF THE GFS AND THE ECMWF THROUGH TONIGHT. FROM MONDAY MORNING ONWARD, THE NHC TRACK IS MOST CLOSELY RESEMBLED BY THE 00Z ECMWF AND 00Z UKMET, WHICH KEPT THE SURFACE LOW FARTHER SOUTH. ...UPPER-LEVEL TROUGH MOVING FROM THE GREAT LAKES INTO THE NORTHEAST TODAY... PRELIMINARY PREFERENCE: GFS/ECMWF/UKMET BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE NAM AND GFS ARE IN GOOD AGREEMENT WITH THE MODEL CONSENSUS THROUGH TONIGHT. AGREEMENT AMONG THE MODELS AFTER TONIGHT HAS IMPROVED WITH THE ARRIVAL OF THE 12Z NON-NCEP GUIDANCE. THE ECMWF AND UKMET HAVE BOTH TRENDED TOWARD A MORE AMPLIFIED TROUGH ACROSS NEW ENGLAND ON MONDAY, SIMILAR TO THE GFS. THE CMC REMAINS WEAKER WITH THE TROUGH, SIMILAR TO THE NAM. WILL MODIFY THE PREFERENCE TO INCLUDE A BLEND OF THE 12Z RUNS OF THE GFS/ECMWF/UKMET. ...UPPER LOW/POSITIVELY TILTED TROUGH IN BRITISH COLUMBIA... ...SFC LOW AND FRONTAL ZONE EMERGING EAST OF THE ROCKIES SUNDAY NIGHT... PRELIMINARY PREFERENCE: GEFS MEAN/ECMWF/UKMET BLEND CONFIDENCE: AVERAGE MODELS HANDLE THIS FEATURE SIMILARLY THROUGH MONDAY AFTERNOON. SPREAD HAS DECREASED SOMEWHAT AFTER THAT TIME. THE LATEST RUNS OF THE UKMET AND ECMWF ARE NOW SLOWER, SIMILAR TO THE NAM. THE GFS IS NOW TOWARD THE FASTER SIDE OF THE SPREAD (ALTHOUGH OVERALL THE SPREAD REMAINS LOW). THE GFS IS ALSO SLIGHTLY FASTER THAN THE GEFS MEAN, WHICH DOES SUGGEST ITS DETERMINISTIC SOLUTION MAY BE SLIGHTLY TOO FAST. WILL CONTINUE TO RECOMMEND A THREE-COMPONENT BLEND INCLUDING THE GEFS MEAN, ECMWF, AND UKMET, WHICH RESULTS IN A SLIGHTLY SLOWER PROGRESSION THAN THE GFS. ...SHORTWAVE MOVING FROM THE FOUR CORNERS INTO THE CENTRAL PLAINS TODAY/TONIGHT... PRELIMINARY PREFERENCE: GFS/ECMWF/UKMET BLEND CONFIDENCE: ABOVE AVERAGE A SHORTWAVE INITIALLY ACROSS THE FOUR CORNERS REGION IS FORECAST TO MOVE EAST INTO THE CENTRAL PLAINS ON MONDAY AND THEN QUICKLY INTO THE GREAT LAKES BY TUESDAY AS THE WAVE GETS PICKED UP BY STRONGER WESTERLY FLOW. AGREEMENT AMONG THE MODELS WITH RESPECT TO THE TIMING AND STRENGTH OF THIS FEATURE HAS IMPROVED OVER THE PAST DAY, AND THE NAM AND GFS NOW HANDLE THE WAVE COMPARABLY TO THE MODEL CONSENSUS. THE GFS, ECMWF, AND UKMET APPEAR TO BE THE SOLUTIONS LOCATED MOST CENTRALLY WITHIN THE RELATIVELY SMALL RANGE OF SPREAD, SO WILL RECOMMEND A BLEND OF THESE THREE SOLUTIONS AT THIS TIME. ...SHORTWAVE REACHING THE CALIFORNIA COAST ON WEDNESDAY... PRELIMINARY PREFERENCE: GFS/GEFS MEAN BLEND CONFIDENCE: AVERAGE A SHORTWAVE IS FORECAST BY ALL DETERMINISTIC GUIDANCE TO REACH THE CALIFORNIA COAST ON WEDNESDAY. THE NAM IS ON THE FAST SIDE OF THE SPREAD WITH THIS WAVE WHILE THE GFS IS WEAKER AND LOOKS MORE LIKE THE 00Z ECMWF ENS MEAN/12Z GEFS MEAN SOLUTIONS. THE ECMWF REMAINS ONE OF THE MOST AMPLIFIED SOLUTIONS WITH THIS WAVE, AND CONTINUES TO BE MORE AMPLIFIED THAN ITS RESPECTIVE 00Z ENSEMBLE MEAN. WILL CONTINUE TO RECOMMEND A BLEND OF THE GFS AND GEFS MEAN AT THIS TIME. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RYAN