MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 133 AM EST MON DEC 28 2015 VALID DEC 28/0000 UTC THRU DEC 31/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF ...DEEP CLOSED LOW OVER THE SOUTHERN PLAINS... ...ENERGY/SURFACE LOW LIFTING NORTHEAST THROUGH THE GREAT LAKES BY TUES... ...SYSTEM SHEARING ACROSS THE NORTHEAST BY WED... ...SECONDARY LOW DEVELOPMENT OVER THE GULF OF MAINE... PREFERENCE: NON-GFS CONSENSUS CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE GUIDANCE SHOWS VERY GOOD AGREEMENT WITH A STRONG CLOSED LOW CENTER EJECTING OUT ACROSS THE ARKLATEX REGION THROUGH EARLY MON AND WILL BE INTERACTING WITH A VERY STRONG FRONTAL ZONE SITUATED OVER THE LOWER MS VALLEY. THE HEIGHT FALLS/JET ENERGY IS ALREADY FOSTERING A DEEPENING AREA OF LOW PRESSURE OVER NORTHEAST TX AND THIS WILL LIFT NORTHEAST ACROSS THE RED RIVER VALLEY BY EARLY MON AND THEN NORTHEAST INTO THE GREAT LAKES REGION BY TUES. THE MID LEVEL LOW CENTER WILL WEAKEN THOUGH RATHER RAPIDLY AS IT REACHES THE GREAT LAKES AND ENCOUNTERS A STRONG MID/UPPER LEVEL CONFLUENCE ZONE OVER SOUTHEAST CANADA AND NEW ENGLAND. BY EARLY WED...A MUCH WEAKER SURFACE LOW WILL EXIT INTO THE ST LAWRENCE RIVER VALLEY...WITH SECONDARY LOW DEVELOPMENT EXPECTED IN THE GULF OF MAINE NEAR NORTHERN NEW ENGLAND. THE NON-GFS GUIDANCE IS COMING INTO RATHER GOOD AGREEMENT AT THIS POINT...WITH THE 00Z GFS AGAIN GRADUALLY BECOMING A TAD FASTER THAN THE MULTI-MODEL CONSENSUS WHICH INCLUDES THE 00Z NAM/00Z UKMET/00Z CMC AND 00Z ECMWF. THE GFS ALSO TRACKS ITS INITIAL LOW CENTER A LITTLE RIGHT OF THIS CONSENSUS AS IT CROSSES THE MIDWEST. WILL MAINTAIN A PREFERENCE TOWARD A NON-GFS CONSENSUS FOR THE EVENT. ...SHORTWAVE TROUGH/FRONT MOVING INTO THE WEST SUN THROUGH TUES... ...CLOSED LOW DEVELOPMENT OVER THE GREAT BASIN BY TUES... ...SYSTEM EJECTING OUT INTO THE PLAINS/UPPER MIDWEST BY WED... PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF CONFIDENCE: AVERAGE A SHORTWAVE TROUGH AND ASSOCIATED FRONTAL ZONE WILL BE APPROACHING THE PACIFIC NORTHWEST BY SUN AND WILL MOVE INTO THE WEST THROUGH MON. THE GUIDANCE GENERALLY SHOWS GOOD AGREEMENT WITH A CLOSED LOW DEVELOPING OVER THE GREAT BASIN BY TUES. THE 00Z NAM GRADUALLY BECOMES A BIT MORE PROGRESSIVE WITH THE ENERGY VERSUS THE MODEL CONSENSUS AS IT CROSSES OUT ACROSS THE PLAINS AND MIDWEST THROUGH WED. THE 00Z NAM AND 00Z CMC ARE ALSO A BIT DEEPER WITH THEIR RESPECTIVE TROUGHING. WILL LEAN TOWARD THE STRONGER MODEL CLUSTERING OF THE 00Z GFS AND 00Z ECMWF AT THIS POINT WHICH ALSO HAS REASONABLY GOOD SUPPORT FROM THE 00Z UKMET. ...COMPACT SHORTWAVE MOVING INTO THE PACIFIC NORTHWEST BY WED... PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE MODELS SHOW A FAIRLY COMPACT SHORTWAVE AND SMALL CLOSED LOW CENTER MOVING INTO THE PACIFIC NORTHWEST TUES NIGHT AND INTERACTING WITH SOME ADDITIONAL NORTHERN STREAM ENERGY OVER SOUTHWEST CANADA THAT WILL ALSO BE DROPPING SOUTHEAST INTO THE NORTHERN ROCKIES. THE 00Z NAM AND TO SOME EXTENT THE 00Z CMC GRADUALLY BECOMES A BIT SLOWER TO DROP THE ENERGY SOUTHWARD INTO THE INTERMOUNTAIN WEST WED AND THURS. THE 00Z CMC ALSO IS PERIODICALLY A BIT DEEPER THAN THE MODEL CONSENSUS. THE 00Z GFS/00Z UKMET AND 00Z ECMWF ARE CLUSTERED JUST A LITTLE FASTER...AND A BLEND OF THESE SOLUTIONS WILL BE PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON