MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 243 AM EDT TUE JUN 28 2016 VALID JUN 28/0000 UTC THRU JUL 01/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SHORTWAVE TROF MOVING THROUGH GREAT LAKES TUES AND EXITING NEW ENGLAND THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z NAM HAS CHANGED VERY LITTLE SUPPORTING A SLOWER AND DEEPER SOLUTION THAN MUCH OF THE SUITE INCLUDING DEVELOPING A SURFACE LOW ALONG THE REMAINING SURFACE CONVERGENCE TROF WED INTO THURS. THE 00Z GFS AND 12Z CMC REMAIN THE FASTER SOLUTIONS WITH RESPECT TO LIFTING THE WAVE NORTHEAST AND WEAKENING RAISING THE HEIGHTS IN THE WAKE BUT HAVE REMAINED FAIRLY CONSISTENT OVER THE LAST DAY OR SO. THE 12Z ECMWF SHIFTED FASTER BUT LAG BEHIND THE GFS/CMC JUST A BIT MANY ALOFT (5H-7H).THE 12Z UKMET IS GENERALLY WEAKER ALLOWING FOR A FASTER NORTHERN SOLUTION IN LINE WITH THE CMC/GFS BUT ALSO LINGERING ENERGY FROM THE BASE OF THE TROF ACROSS THE MID-ATLANTIC A BIT LONGER LIKE THE ECMWF. ENSEMBLE MEANS SUPPORT THEIR OPERATIONAL MODEL SOLUTIONS...AND AS SUCH WILL FAVOR A NON-NAM BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE GIVEN OVERALL SPREAD IS REDUCING BUT STILL NOTABLE. 07Z UPDATE: THE 00Z ECMWF/UKMET REMAIN FAIRLY UNCHANGED WHILE THE 00Z CMC TRENDED BACK TOWARD THE SLOWER ECMWF. STILL THE EFFECTIVE DIFFERENCES STILL LEAVE THE NAM AS THE MAIN OUTLIER AND SEEN NO REASON TO CHANGE THOUGHTS ON PREFERENCE/CONFIDENCE. NEXT SHORTWAVE TROF AND ASSOCIATED COLD FRONT MOVING INTO WESTERN GREAT LAKES THURS/FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/ECMWF/UKMET CONFIDENCE: SLIGHTLY ABOVE AVERAGE AN ARCTIC STREAM SHORTWAVE AND COLD FRONT DESCEND OUT OF MANITOBA/W ONTARIO BY THURS TO IMPACT N MN BOUNDARY WATERS AND WESTERN GREAT LAKES BY FRI. INITIALLY THE MODELS ARE ALIGNED BY 30/12Z WITH ONLY THE CMC LEADING FORWARD A SLIGHT FAVORING AN EVER SO SLIGHTLY SOUTHERN PUSH (CENT IN/OH) TO THE TROF...BUT NOT DRAMATICALLY SO BY THE END OF DAY 3 COMPARED TO WELL ALIGNED 00Z GFS/GEFS AND 12Z ECMWF/ECENS MEAN. LIKEWISE BY FRIDAY THE UKMET DID SHOW SOME FASTER PROGRESSION WITH THE BASE OF THE TROF AND SURFACE FRONT ACROSS MI/N OH THAN THE REST. THE 00Z NAM...HOWEVER IS THE LARGEST OUTLIER WITHIN THE MOST RECENT DETERMINISTIC RUNS CONTINUING TO FAVOR A MORE CONSOLIDATED LOW THAN UPPER LEVEL TROF WITH A DEEPER AND FURTHER NORTH SURFACE REFLECTION ACROSS ONTARIO/S JAMES BAY BY FRIDAY. EVEN THE 21Z SREF IS MORE ALIGNED WITH THE GEFS/ECENS MEAN AND THE 00Z GFS/12Z ECMWF. AS SUCH WILL FAVOR A 00Z GFS/12Z ECMWF BLEND (WITH SOME USE OF THE SREF/GEFS/ECENS MEAN TO STABILIZE SMALL DIFFERENCES IN THE MASS FIELDS). CONFIDENCE IS SLIGHTLY ABOVE AVERAGE FOR THIS BLEND. 07Z UPDATE: THE 00Z CMC CONTINUED A TREND OF SLIGHTLY DEEPER/SOUTH WITH THE S/W AS WELL AS GENERATING A STRONGER SFC WAVE NEAR LK SUPERIOR. LITTLE CHANGES WITH THE 00Z GEFS AND 00Z ECMWF CONTINUE TO PROVIDE STRENGTH/CONFIDENCE WITH THE EARLIER PREFERENCE. THE 00Z UKMET HAS SLOWED A BIT AND WITHIN PROXIMITY OF THE PREFERRED GFS/ECMWF WITH RESPECT TO THE WAVE AND THE FRONT (THOUGH A BIT WEAKER IN GENERAL FURTHER SOUTH); IT IS OK TO INCLUDE THIS RUN WITH THE PREFERENCE IF DESIRED. WEAK SURFACE WAVE CENTRAL ROCKIES FRONT RANGE BY WED DROPPING INTO TX/OK PANHANDLES BY FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-CMC BLEND CONFIDENCE: ABOVE AVERAGE INDIVIDUAL SHORTWAVE ENERGY MOVING THROUGH THE MEAN RIDGE ACROSS THE NORTHERN ROCKIES WILL CONTINUE TO FIRE CONVECTION ALONG THE FRONT RANGE WITH FAIRLY LARGE SPREAD IN THE QPF FIELDS. THIS SEEMS TO REMAIN THE MORE SIGNIFICANT ISSUE AS THE MASS FIELDS REMAIN FAIRLY TIGHTLY PACKED IN TIMING/PLACEMENT AND STRENGTH OF THE WEAK SURFACE LOW THAT DEVELOPS IN WY TUESDAY N AND TRACKS THROUGH CO WED/THUR BEFORE WEAKENING THROUGH THE TX/OK PANHANDLES BY FRI. AN OPERATIONAL MODEL BLEND IS PREFERRED AT ABOVE AVERAGE CONFIDENCE FOR THE MASS FIELDS...THOUGH PLEASE REFER TO QPFPFD FOR SPECIFIC MODEL PREFERENCES/DETERMINATION REGARDING QPF. 07Z UPDATE: BY FRIDAY THE CMC IS OUT OF PHASE WITH THE QPF ORIENTATION AND SURFACE PATTERN ACROSS THE CENTRAL PLAINS. WHILE THERE REMAIN THE VARIATION BETWEEN THE OTHER DETERMINISTIC RUNS WITH RESPECT TO QPF...THEY ARE MORE ALIGNED IN EVOLUTION/SETUP THAN THE CMC TO SUPPORT ITS REMOVAL TO A NON-CMC BLEND AT HIGH CONFIDENCE (FOR MASS FIELDS AT LEAST). www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GALLINA