MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 157 AM EST THU FEB 16 2017 VALID FEB 16/0000 UTC THRU FEB 19/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION AND FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...CLOSED LOW DEVELOPMENT OVER NORTHEAST TODAY... ...SURFACE LOW OFFSHORE OF THE NEW ENGLAND COAST TONIGHT THROUGH THURSDAY... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE 00z NCEP MODELS CONTINUE TO HANDLE THIS FEATURE SIMILARLY...AND COMPARE FAVORABLY TO 12Z ECMWF/CMC/UKMET...SUCH THAT A GENERAL MODEL BLEND REMAINS THE PREFERENCE WITH THIS FEATURE. ...COLD FRONT MOVING ACROSS THE WEST COAST TODAY...REACHING THE N-CNTRL U.S. FRI MORNING... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/NAM & 12Z ECMWF CONFIDENCE: AVERAGE GOOD AGREEMENT WITH THE EVOLUTION OF THE LEAD SHORTWAVE PUSHING ACROSS THE INTERMOUNTAIN WEST THROUGH THURSDAY NIGHT...REACHING THE NORTHERN PLAINS ON FRIDAY. FROM THAT POINT ONWARD...THE 00Z NAM TRENDED A BIT QUICKER TOWARD THE REMAINING CONSENSUS. THE 12Z UKMET IS A BIT QUICKER THAN THE REMAINDER OF THE GUIDANCE ENVELOPE WITH THIS FEATURE AND THE ATTENDANT COLD FRONT...BUT IS TRENDING IN THE RIGHT DIRECTION TIMING-WISE WITH THE PAST FEW RUNS. A BLEND OF THE 12Z ECMWF...00Z NAM AND GFS WILL BE USED AT ABOVE AVERAGE CONFIDENCE. ...SHARPENING UPPER TROUGH WEST OF CALIFORNIA FRI/SAT... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 18Z GEFS/18Z GFS/00Z EC ENS MEAN CONFIDENCE: SLIGHTLY BELOW AVERAGE RUN TO RUN INCONSISTENCIES PERSIST...ESPECIALLY TOWARD THE END OF THE PERIOD. THE 00Z GFS HAS TRENDED A BIT STRONGER/FASTER...AND IS A BIT AHEAD OF THE REST OF GUIDANCE WITH THIS SOLUTION. THE LATEST 18Z GFS PARALLEL MESHES WELL WITH THE 18Z GEFS AND 12Z EC ENS. 00Z NAM HAS TRENDED DEEPER TOWARD THE MAJORITY OF GUIDANCE...AND ITS TIMING TOO IS SIMILAR TO THE 18Z GEFS/12Z ECENS CAMP. 12Z ECMWF AND 12Z UKMET WITH MASS FIELDS...AND CLUSTER WELL WITH A MAJORITY OF ENSEMBLE MEMBERS. THE 12Z CMC REMAINS A BIT SHALLOWER/FASTER WITH THE UPPER TROUGH OVER THE CA COAST. HOWEVER...THE 18Z NAEFS IS A BIT DEEPER TOWARD THE GEFS AND ECENS...SO THERE IS SOME HOPE THAT THE 00Z CMC WILL TREND TOWARD THE GROWING MODEL CONSENSUS. WILL BLEND THE 18Z GEFS/GFS WITH THE 12Z ECENS TO REFLECT THE MIDDLE GROUND SOLUTION GOING FORWARD. ...UPPER TROUGH OVER THE SOUTHERN PLAINS/NORTHERN MEXICO TODAY THROUGH FRI... ...SYSTEM EJECTING EAST ACROSS THE DEEP SOUTH LATE FRI/SAT... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS...12Z ECMWF BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z NAM HAS TRENDED TOWARD THE 12Z ECMWF SOLUTION WITH THE HANDLING OF THE EJECTING AND SHEARING MID-LEVEL LOW OVER THE SOUTHERN PLAINS...AND THIS SOLUTION IS WELL SUPPORTED BY THE MEMBER ENSEMBLES. THE 00Z GFS IS NOW A BIT QUICKER WITH TRAVERSING THE OPEN WAVE ACROSS THE DEEP SOUTH TOWARD THE LOWER MID-ATLANTIC BY SUNDAY. THE 12Z CMC IS A BIT FASTER WITH THE PROGRESSION OF THE UPPER TROUGH ACROSS THE LOWER MS VALLEY...AND THE 12Z UKMET IS A BIT STRONGER AND TO THE SOUTH WITH A CLOSED UPPER LOW OVER OK/TX EARLY SATURDAY...WHICH IS AT THE STRONG SIDE OF THE GUIDANCE ENVELOPE. A MIDDLE GROUND SOLUTION WILL BE MAINTAINED HERE AS WELL...WITH A 50/50 BLEND OF THE DEEPER/SLOWER ECMWF AND THE MORE PROGRESSIVE 00Z GFS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... MONTEFUSCO