MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 235 PM EDT WED JUN 15 2016 VALID JUN 15/1200 UTC THRU JUN 19/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION WITH FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CLOSED LOW SLOWLY EXITING NEW ENGLAND THROUGH THU MORNING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE THE MODELS SHOW SIMILARLY WITH THIS SYSTEM. SHORTWAVE TRACKING FROM THE UPPER MISSISSIPPI VALLEY TODAY TO THE MID-ATLANTIC FRI SURFACE LOW FORMING OVER THE MID ATLANTIC FRI AFTERNOON/EVENING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z NAM...12Z GFS...12Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z NAM...12Z GFS...00Z ECMWF REPRESENT THE EDGES OF A MODERATELY TIGHT CLUSTER OF ENSEMBLE MEMBERS REGARDING 500 MB LOW PLACEMENT AND SURFACE LOW PLACEMENT. FOR THE 850 MB LOW VALID 12Z/17 ALONG THE MID-ATLANTIC COAST...RELATIVELY SPEAKING COMPARED TO THE REMAINING DETERMINISTIC GUIDANCE...THE 12Z NAM REPRESENTS THE MIDDLE BUT STRONGER SIDE...THE 12Z GFS REPRESENTS THE SRN/WEAKER SIDE AND THE 00Z ECMWF THE NRN/MIDDLE-STRENGTH SIDE OF THE GUIDANCE. THE 12Z ECMWF ADJUSTED SOUTH TOWARD THE REMAINING GUIDANCE WHILE THE OTHER MODELS FALL IN THE MIDDLE OF THE LATEST GUIDANCE. THEREFORE...GIVEN THE RELATIVELY TIGHT CLUSTERING AND CENTRAL PLACEMENT OF THE AVERAGE OF THE NAM/GFS/ECMWF WITH RESPECT TO THE LATEST ENSEMBLE GUIDANCE...A BLEND OF THE 3 MODELS IS PREFERRED WITH AVERAGE CONFIDENCE. EXPECT MINOR RUN TO RUN VARIATIONS WITH FUTURE MODEL CYCLES...BUT A SIGNIFICANT DEVIATION FROM THE AVERAGE OF THE NAM/GFS/ECMWF WOULD NOT PREFERRED. COLD FRONT ENTERING THE NRN HIGH PLAINS THU ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE DESPITE SOME MINOR TIMING ADJUSTMENTS MADE BY THE 12Z ECMWF/UKMET COMPARED TO THEIR 00Z RUNS...THE MODELS SHOW SIMILARLY WITH THIS SYSTEM. CLOSED LOW OVER THE PACIFIC NORTHWEST THROUGH SAT MORNING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z GFS/12Z ECMWF BLEND CONFIDENCE: AVERAGE TRENDS OVER THE PAST 24 HOURS HAVE BEEN TO THE WEST WITH A CLOSED LOW OFF OF THE PACIFIC NORTHWEST BY THE END OF THE WEEK...EXCLUDING THE 12Z UKMET/CMC WHICH EDGED EAST COMPARED TO THEIR PREVIOUS 00Z CYCLES. SINCE THE 00Z UKMET STOOD OUT GREATEST FROM THE REMAINING DETERMINISTIC CLUSTERING OF MODELS IN BEING FARTHEST OFFSHORE WITH THE MID-LEVEL LOW...A SHIFT TO THE EAST DOES NOT APPEAR TO BE A BAD THING. THE 12Z GFS AND 12Z ECMWF ARE CLOSEST TO THE MIDDLE OF THE SPREAD WITH THE 12Z CMC ADJUSTING TOO FAR EAST OF THE CONSENSUS TO REMAIN INCLUDED IN THE PREFERRED BLEND. THE 12Z NAM COULD BE A BIT TOO AGGRESSIVE WITH MID-LEVEL VORT ENERGY MOVING INTO WASHINGTON FRI EVENING...WITH THE MAJORITY OF REMAINING MODELS A BIT WEAKER/LESS PROGRESSIVE TOWARD THE EAST. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... OTTO