MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 135 AM EST FRI FEB 13 2015 VALID FEB 13/0000 UTC THRU FEB 16/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM AND ECMWF ...UPPER TROUGH APPROACHING THE PACIFIC NORTHWEST FRI EVENING... ...DOWNSTREAM AMPLIFICATION INTO THE PLAINS BY SUN... PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF CONFIDENCE: AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH A SHORTWAVE MOVING THROUGH THE PACIFIC NORTHWEST FRI NIGHT AND EARLY SAT...ALTHOUGH THE 00Z UKMET GRADUALLY BECOMES A STRONG OUTLIER WITH THE ENERGY AS IT DIGS ACROSS THE INTERMOUNTAIN WEST AND TOWARD THE HIGH PLAINS SUN AND MON. ALL OF THE MODELS SHOW AN INVERTED TROUGH DEVELOPING OVER THE SOUTHERN PLAINS AND LOWER MS VALLEY REGION SUN AND MON. THE 00Z UKMET IS THE STRONGEST SOLUTION AT THE SURFACE...WITH THE 00Z NAM THE FLATTEST. THE STRONGER MODEL CLUSTERING FAVORS A 00Z GFS AND 00Z ECMWF CONSENSUS WHICH RESIDES IN BETWEEN STRONGER AND WEAKER CAMPS AND HAS REASONABLY GOOD ENSEMBLE SUPPORT. THIS CONSENSUS IS ALSO SUPPORTED RATHER WELL BY THE 00Z GEM. ...POWERFUL UPPER TROUGH/VORTEX CROSSING THE GREAT LAKES AND NORTHEAST... ...INTENSE SURFACE LOW DEVELOPMENT OFF NEW ENGLAND ON SUN... PREFERENCE: NON-GEM CONSENSUS CONFIDENCE: AVERAGE ON THE LARGER SCALE...THE MODELS ARE IN EXCELLENT AGREEMENT ON A POWERFUL TROUGH AMPLIFYING ACROSS THE GREAT LAKES REGION AND THROUGH THE NORTHERN MID-ATLANTIC AND NEW ENGLAND SAT AND SUN. THE GUIDANCE SHOWS AN INTENSE VORTEX EMBEDDED WITHIN THE TROUGH CROSSES THE REGION...AND THIS ENERGY IS EXPECTED TO RESULT IN A VERY INTENSE LOW CENTER DEVELOPING OFFSHORE NEW ENGLAND ON SUN. AFTER ABOUT 48 HOURS...THE 00Z GFS AND 00Z UKMET TEND TO BE A BIT FASTER THAN THE 00Z NAM/00Z ECMWF AND 00Z GEM WITH THE HEIGHT FALL EVOLUTION. HOWEVER...AT THE SURFACE...THERE IS ACTUALLY FAIRLY GOOD AGREEMENT WITH THE IDEA OF A VERY INTENSE LOW CENTER WRAPPING UP CLOSE TO THE 40N/70W BENCHMARK AND THEN LIFTING NORTH TO NEAR THE GULF OF MAINE SUN MORNING. THE GFS AND ECMWF ARE A BIT LEFT OF THE NAM AND UKMET...WITH THE GEM BECOMING A BIT OF AN OUTLIER IN BEING A BIT FARTHER SOUTH AND EAST AND ALSO SOMEWHAT SLOWER. THE LATEST SPREAD WITHIN THE GEFS AND ECENS MEMBERS FAVORS THE IDEA OF GOING WITH A NON-GEM CONSENSUS...OR ESSENTIALLY A BLEND OF THE NAM/GFS/UKMET AND ECMWF SOLUTIONS. ...CLOSED UPPER LOW DRIFTING WEST OF THE BAJA PENINSULA ON SAT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE HAS BROAD AGREEMENT WITH THIS SYSTEM. THE LATEST DETERMINISTIC/ENSEMBLE MODEL CONSENSUS CAN BE USED. ...SHORTWAVE ENERGY DIVING INTO THE NORTHWEST BY MON... PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF CONFIDENCE: AVERAGE THE MODELS ARE IN GOOD AGREEMENT WITH A SHORTWAVE ROUNDING THE TOP OF A STRENGTHENING RIDGE JUST OFF THE WEST COAST...WITH THE ENERGY THEN DIGGING DOWN THROUGH SOUTHWEST CANADA AND INTO THE NORTHWEST BY MON. THE 00Z NAM AND 00Z UKMET ARE A LITTLE FASTER THAN THE 00Z GFS/00Z ECMWF AND 00Z GEM. THE STRONGER MODEL CLUSTERING WOULD TEND TO FAVOR A BLEND OF THE GFS AND ECMWF AND THAT WILL BE THE PREFERENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON