MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 239 AM EDT TUE JUN 14 2016 VALID JUN 14/0000 UTC THRU JUN 17/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION WITH FINAL PREFERENCES AND FORECAST CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SYSTEMS MOVING THROUGH NEW ENGLAND THROUGH TUE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE THE 00Z NAM WAS VERY CLOSE TO THE MODEL CONSENSUS WITH CLOSED MID LEVEL SYSTEM CROSSING NOVA SCOTIA TUE...WHILE THE 00Z GFS BECOMES A BIT FASTER THAN THE CONSENSUS AS THE SYSTEM CROSSES NEWFOUNDLAND. HOWEVER...THE TIMING AND STRENGTH OF THE DEEP CYCLONE REMAINS CLOSE ACROSS THE MODEL SOLUTION SPECTRUM...SO A GENERAL MODEL BLEND IS PREFERRED. LONG WAVE TROUGH CROSSING THE LOWER MS VALLEY/SOUTHEAST STATES TUE INTO WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE THE 00Z NAM REMAINS MORE AMPLIFIED WITH THE LONG WAVE TROUGH INTO EARLY WED...BEFORE IT WEAKENS AND JOINS THE REMAINDER OF THE GUIDANCE TAKING THE WEAKENING SYSTEM OFF THE SOUTHEAST COAST. THE 00Z GFS REMAINS CLOSE TO THE CONSENSUS THROUGHOUT. THE GUIDANCE REMAINS TIGHTLY CLUSTERED WITH THIS SYSTEM...SO A GENERAL MODEL BLEND IS PREFERRED. SHORTWAVE OVER THE CENTRAL PLAINS EVOLVING INTO A CLOSED MID LEVEL SYSTEM IN THE UPPER MS VALLEY LATER TUE BEFORE ROLLING OVER TOP THE RIDGE INTO GREAT LAKES BY THU WITH ASSOCIATED SURFACE LOW ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/UKMET/ECMWF BLEND CONFIDENCE: BELOW AVERAGE WHILE THE 00Z NAM/GFS ARE CLOSE TO THE CONSENSUS WITH THE SHORT WAVE AS IT ROLLS OVER THE TOP OF THE RIDGE OVER INTO THE OH VALLEY AND EVENTUALLY MID ATLANTIC BY EARLY THU...THERE IS QUITE A BIT OF SPREAD IN THE PLACEMENT OF THE SURFACE LOW ASSOCIATED WITH THE SHORT WAVE. THE 00Z NAM APPEARS TO BE TOO FAR NORTH AND TOO STRONG WITH THE SURFACE LOW THAT DEVELOPS NEAR THE MID ATLANTIC COAST. THE 00Z GFS IS FURTHER SOUTHWEST WITH THE SURFACE LOW...WHICH EARLIER APPEARED TO BE TOO FAR SOUTHWEST. HOWEVER...THE 00Z ECMWF HAS COME CLOSER TO THE 00Z GFS SOLUTION (AS WELL AS THE 00Z UKMET)...SO IT IS POSSIBLE THAT THERE IS SOME CONVERGENCE TO A COMMON PLACEMENT OF THE LOW OCCURRING. THE 00Z CMC APPEARS TO BE TOO FAR EAST WITH THE SURFACE LOW...BUT IT IS ON GENERALLY THE SAME LATITUDE AS THE 00Z ECMWF/UKMET. GIVEN THAT THERE IS STILL SOME VOLATILITY IN THE PLACEMENT OF THE SURFACE LOW (GIVEN THE FAIRLY LARGE CHANCE IN THE 00Z ECMWF POSITION)...FORECAST CONFIDENCE REMAINS BELOW AVERAGE. EASTERN PORTION OF BROAD MID LEVEL LOW THAT CLOSES OFF AND LIFTS FROM PACIFIC NW INTO CENTRAL CANADA TUE INTO WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-GFS BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z NAM IS CLOSE TO THE CONSENSUS WITH THE TIMING OF THE CLOSED MID LEVEL SYSTEM AS IT TRACKS ACROSS ALBERTA INTO MANITOBA WED INTO THU. THE 00Z GFS HAS BECOME PROGRESSIVELY FASTER WITH THIS SYSTEM...BECOMING THE FASTEST PIECE OF GUIDANCE. THE 00Z UKMET/CMC/ECMWF ARE FAIRLY CLOSE TO THEIR PREVIOUS SOLUTIONS...SO THE PREFERENCE IS FOR A NON-GFS SOLUTION. WESTERN PORTION OF BROAD UPPER LOW THAT CLOSED OFF NEAR THE PACIFIC NORTHWEST LATE WED...THEN BECOMES QUASI STATIONARY THROUGH THU NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z NAM/00Z ECMWF/00Z GEFS MEAN BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z NAM HAS SLOWED ITS MOVEMENT OF THE CLOSED MID LEVEL SYSTEM APPROACHING THE PACIFIC NORTHWEST COAST LATE WED INTO THU...AND HAS JOINED THE CONSENSUS KEEPING THE MAIN CIRCULATION JUST OFFSHORE. IT IS NOW VERY CLOSE TO THE 00Z ECMWF/UKMET SOLUTIONS...WHICH HAS THE SUPPORT OF THE 00Z GEFS MEAN. THE 00Z GFS IS FASTER THAN THE CONSENSUS BRING THE MAIN CIRCULATION THE COAST...AND HAS BEEN SPEEDING UP DURING THE PAST THREE MODEL RUNS. IT IS ALSO FASTER THAN THE 00Z GEFS MEAN. THE 00Z UKMET HAS SLOWED ITS APPROACH...AND NOW REPRESENTS THE WESTERN EDGE OF THE GUIDANCE ENVELOPE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... HAYES