MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 200 PM EST THU DEC 03 2015 VALID DEC 03/1200 UTC THRU DEC 07/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF ...CLOSED LOW MOVING OVER THE NORTHEAST TODAY AND TONIGHT... ...DEEPENING SURFACE LOW NEAR DOWNEAST MAINE... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS ARE IN GOOD AGREEMENT WITH THEIR RESPECTIVE MASS FIELDS IN HANDLING THE CLOSED LOW CROSSING NORTHERN NEW ENGLAND TODAY THROUGH THIS EVENING. LOW PRESSURE WILL EXIT THROUGH THE GULF OF MAINE LATER TODAY AND CROSS ALONG THE SOUTH COAST OF NOVA SCOTIA TONIGHT. A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...SOUTHERN STREAM ENERGY CROSSING MOVING INTO THE SOUTHEAST BY SAT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THERE IS RATHER MINIMAL MASS FIELD SPREAD WITH THIS SYSTEM...AND SO A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...PROGRESSIVE SHORTWAVE MOVING THROUGH THE GREAT LAKES AND NORTHEAST ON FRI/FRI NIGHT... PREFERENCE: NON-CMC CONSENSUS CONFIDENCE: SLIGHTLY ABOVE AVERAGE THERE IS OVERALL GOO AGREEMENT AMONG THE MODELS WITH THIS SYSTEM...BUT THE 00Z CMC TENDS TO BECOME A BIT SLOWER AND DEEPER THAN THE MULTI-MODEL CONSENSUS AS THE ENERGY REACHES THE NORTHEAST. WILL PREFER A NON-CMC CONSENSUS AS A RESULT. ...SURFACE LOW APPROACHING THE PACIFIC NORTHWEST TODAY... PREFERENCE: 00Z ECMWF CONFIDENCE: AVERAGE THE MODELS SHOW A STRONG SHORTWAVE TROUGH FOCUSING A DEEPENING AREA OF LOW PRESSURE JUST OFF THE WEST COAST OF NORTHERN CA AND OR TODAY WHICH WILL LIFT NORTH AND CROSS THE COASTAL VICINITIES OF THE PACIFIC NORTHWEST BY THIS EVENING AND THEN LIFT INTO SOUTHWEST BRITISH COLUMBIA TONIGHT. THE 00Z UKMET AND 00Z CMC TEND TO BE A LITTLE SLOWER THAN THEN MULTI-MODEL CONSENSUS...WITH THE 12Z NAM AND ESPECIALLY THE 12Z GFS A BIT MORE PROGRESSIVE. THE 00Z ECMWF OFFERS A NICE COMPROMISE SOLUTION IN BETWEEN SLOWER AND FASTER CAMPS...AND SO WILL LEAN TOWARD THE ECMWF AT THIS TIME. ...SPLIT FLOW TROUGH CROSSING THE WEST AND EJECTING OUT INTO THE PLAINS/MIDWEST BY SAT... PREFERENCE: GENERAL MODEL COMPROMISE...THROUGH 48 HOURS BLEND OF THE 12Z NAM AND 00Z ECMWF...AFTER 48 HOURS CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE AFTER 48 HOURS THE GUIDANCE SHOWS A SPLIT FLOW TROUGH CROSSING THE WEST THROUGH FRI...AND THEN EJECTING OUT ACROSS THE PLAINS ON SAT WITH A MORE DISTINCT SEPARATION OF STREAMS TAKING PLACE BY THEN. SOUTHERN ENERGY IS EXPECTED TO AMPLIFY OUT ACROSS THE CENTRAL AND SOUTHERN PLAINS AND MOVE INTO THE MIDWEST BY SUN. FLATTER NORTHERN STREAM ENERGY WILL FOCUS UP ACROSS THE NORTHERN PLAINS AND UPPER MS VALLEY. THE DIFFERENCES IN THE GUIDANCE ARE MAINLY ASSOCIATED WITH THE SOUTHERN STREAM ENERGY AND ITS AMPLIFICATION THROUGH THE MID MS VALLEY AND LOWER OH VALLEY BY LATE SUN. THE 00Z UKMET GRADUALLY BECOMES A FAST OUTLIER WITH THIS ENERGY...WITH THE 12Z GFS THE SLOWEST. THE 00Z CMC IS A BIT SLOWER AND DEEPER THAN THE UKMET SOLUTION. MEANWHILE...THE 12Z NAM AND 00Z ECMWF CLUSTER TOGETHER RATHER WELL IN BETWEEN THE SLOW GFS AND THE FASTER CMC/UKMET SOLUTIONS. THE 12Z NAM AND 00Z ECMWF DO HAVE REASONABLE GOOD SUPPORT FROM THE 00Z ECENS MEAN...AND SO A BLEND OF THE NAM AND GFS WILL BE PREFERRED AFTER ABOUT 48 HOURS WHEN THE GUIDANCE BEGINS TO SHOW NOTABLE TIMING DIFFERENCES. ...UPPER TROUGH AXIS OFF OF THE WEST COAST SUN MORNING... PREFERENCE: BLEND OF THE 12Z NAM/12Z GFS AND 00Z ECMWF CONFIDENCE: AVERAGE THE 12Z NAM/12Z GFS AND 00Z ECMWF SHOW THE BEST AGREEMENT OF THE LATEST DETERMINISTIC GUIDANCE WITH THIS NEXT SURGE OF ENERGY APPROACHING THE WEST COAST AND MOVING INLAND BY SUN. THE 00Z CMC APPEARS A BIT TOO SLOW WITH ENERGY APPROACHING OFFSHORE...AND THE 00Z UKMET SHOWS A SHARPER SOUTHERN STREAM SHORTWAVE VERSUS THE MULTI-MODEL CONSENSUS. WILL PREFER A CONSENSUS THEREFORE OF THE NAM/GFS AND ECMWF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON