MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 242 PM EDT SAT JUN 25 2016 VALID JUN 25/1200 UTC THRU JUN 29/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 12Z MODEL GUIDANCE ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... ...SHORTWAVE CURRENTLY EXITING LOWER NEW ENGLAND... ...EVENTUAL RETROGRESSION OF THIS FEATURE BACK TOWARD THE NORTHEASTERN U.S... FINAL PREFERENCE: NON-12Z UKMET MODEL COMPROMISE FORECAST CONFIDENCE: AVERAGE A SHORTWAVE TROUGH CURRENTLY MOVING AWAY FROM THE DELMARVA PENINSULA WILL GRADUALLY GET HUNG UP AS IT ENCOUNTERS A STRONG UPPER RIDGE ACROSS THE CENTRAL ATLANTIC. MODELS DEPICT A CLOSED LOW GRADUALLY EVOLVING AROUND 65W LONGITUDE WITH THE SYSTEM EVENTUALLY RETROGRADING. AFTER EVALUATING ALL OF THE LATEST GUIDANCE...THE AGREEMENT IS BETTER THAN PREVIOUS BUT THE 12Z UKMET STILL DIVERGES FROM THE REST OF THE GROUP. WHILE NOT AS FAR NORTH AS THE PRIOR SOLUTION...IT STILL IS A SUBTLE OUTLIER. DETERMINISTIC CLUSTERING HAS IMPROVED ENOUGH DURING THE 12Z MODEL CYCLE TO SHIFT THE PREFERENCE TO A NON-12Z UKMET MODEL COMPROMISE. ...AMPLIFIED UPPER TROUGH/SURFACE FRONT ACCELERATING THROUGH THE NORTHERN TIER STATES... ...TRAILING HEIGHT FALLS TRAVERSING ACROSS THE LOWER GREAT LAKES BY TUESDAY... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF FORECAST CONFIDENCE: ABOVE AVERAGE AN IMPRESSIVE UPPER TROUGH CURRENTLY MOVING THROUGH THE CANADIAN/NORTHERN ROCKIES WILL CONTINUE TO SURGE EASTWARD WITH THE RESULTANT CLOSED LOW REACHING WESTERN ONTARIO BY 26/1800Z. AS THE CORE OF LOWER HEIGHTS REMAIN IN EASTERN CANADA...ADDITIONAL HEIGHT FALLS ARE FORECAST TO TRAVERSE THE UPPER MIDWEST/GREAT LAKES ON MONDAY. ONE NOTABLE CHANGE IN THE RECENT MODELS IS THE 12Z ECMWF HAS PUSHED EASTWARD TO GENERALLY FOLLOW THE CAMP TO THE EAST. THIS NOW LEAVES THE 00Z ECMWF ENSEMBLE MEAN ON THE SLOWER END OF THINGS. GIVEN THIS ADJUSTMENT...FEEL COMFORTABLE ADDING THE 12Z ECMWF TO THE MIX WITH THE 12Z GFS. ...TUTT CELL SLOWLY DRIFTING ACROSS WEST TX... FINAL PREFERENCE: A NON-12Z NAM MODEL CONSENSUS FORECAST CONFIDENCE: AVERAGE WATER VAPOR IMAGERY SHOWS A BROAD CIRCULATION CURRENTLY MOVING ACROSS THE BIG BEND OF TX WHICH HAS FIRED SCATTERED CONVECTION TO ITS EAST. THE MOTION OF THIS FEATURE WILL BE QUITE SLOW AS IT DRIFTS NORTHWARD TOWARD A WEAKNESS IN THE BROAD WEST-EAST ORIENTED RIDGE. SOME SOLUTIONS EVENTUALLY DRAG THE TUTT CELL BACK TOWARD THE SOUTH...PARTICULARLY THE 12Z NAM. WILL CONTINUE TO STICK WITH THE CONSENSUS TO THE NORTH WHERE ENSEMBLES SUPPORT KEEPING THE SYSTEM. A NON-12Z NAM MODEL CONSENSUS IS RECOMMENDED. ...WEAK/LOW-AMPLITUDE IMPULSE MOVING THROUGH THE PACIFIC NORTHWEST ON MONDAY... FINAL PREFERENCE: A NON-12Z/00Z CMC MODEL CONSENSUS FORECAST CONFIDENCE: ABOVE AVERAGE AS THE PRIMARY BAND OF HEIGHT FALLS EJECT TOWARD THE GREAT PLAINS...SHORTWAVE RIDGING SETS UP ALONG THE WEST COAST. EVENTUALLY A LOW AMPLITUDE IMPULSE MOVES TOWARD THE PACIFIC NORTHWEST COAST BY MONDAY MORNING. MODELS ARE IN DECENT AGREEMENT WITH THE EXCEPTION OF THE 12Z/00Z CMC WHICH ARE SLOWER BASED ON THE 500-MB HEIGHT PATTERN. WILL RECOMMEND A NON-12Z/00Z CMC MODEL CONSENSUS GIVEN THIS ARTIFACT. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RUBIN-OSTER