MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1228 AM EDT SAT AUG 27 2016 VALID AUG 27/0000 UTC THRU AUG 30/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...LOW LEVEL WAVE EXITING THE LOWER MO VALLEY EARLY SAT... PREFERENCE: NON-NAM CONSENSUS CONFIDENCE: ABOVE AVERAGE THE 00Z NAM TENDS TO HANG ONTO A SOMEWHAT STRONGER SURFACE LOW THAT LIFTS OUT OF THE LOWER MO VALLEY EARLY SAT AND CROSSES THE UPPER GREAT LAKES REGION THROUGH THE DAY. VERY GOOD MASS FIELD AGREEMENT SEEN OTHERWISE...AND SO A NON-NAM CONSENSUS WILL BE PREFERRED. ...UPPER TROUGH CROSSING NORTHERN PLAINS/UPPER MIDWEST ON SAT... ...ENERGY CROSSING OVER TO NEW ENGLAND ON MON... PREFERENCE: NON-NAM CONSENSUS CONFIDENCE: ABOVE AVERAGE THE 00Z NAM IS A STRONGER AND SOMEWHAT FASTER OUTLIER WITH THIS SYSTEM. THE REMAINING GUIDANCE SHOWS GOOD AGREEMENT AND SO A NON-NAM CONSENSUS WILL BE PREFERRED WITH THIS TOO. ...UPPER TROUGH DROPPING SOUTH THROUGH BRITISH COLUMBIA ON SAT... ...ENERGY CROSSING SOUTHERN CANADA SUN/MON... ...COLD FRONT MOVING THROUGH THE NORTHERN PLAINS/UPPER MIDWEST SUN/MON... PREFERENCE: BLEND OF THE 00Z GFS/12Z UKMET AND 12Z ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 12Z CMC REMAINS A BIT DEEPER AND SLOW WITH THIS SYSTEM COMPARED TO THE REMAINING GUIDANCE. THE 00Z NAM ALSO IS A BIT DEEP WITH THE UPPER TROUGH...BUT IS NOTABLY SLOW WITH ITS COLD FRONT THAT CROSSES SOUTHERN CANADA AND THE NORTHERN PLAINS. BETTER MODEL CLUSTERING RESIDES WITH THE 00Z GFS/12Z UKMET AND 12Z ECMWF WHICH AGAIN TENDS TO HAVE BETTER ENSEMBLE SUPPORT AS WELL. ...UPPER TROUGH DIGGING SOUTH OFFSHORE BRITISH COLUMBIA BY MON... PREFERENCE: BLEND OF THE 00Z GFS/12Z UKMET AND 12Z ECMWF CONFIDENCE: AVERAGE THE 00Z NAM REMAINS A BIT FASTER THAN THE MULTI-MODEL CONSENSUS IN BRINGING THIS NEXT UPPER TROUGH OFFSHORE BRITISH COLUMBIA AND APPROACHING THE PACIFIC NORTHWEST. THE STRONGER MODEL CLUSTERING RESIDES WITH THE 00Z GFS/12Z UKMET AND 12Z ECMWF...AND A BLEND OF THESE SOLUTIONS WILL BE PREFERRED. ...WEAK MID LEVEL TROUGH OVER THE SOUTHWEST THIS WEEKEND... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: ABOVE AVERAGE WHILE THERE IS BROAD AGREEMENT WITH THE EVOLUTION OF THIS FEATURE...THE 00Z NAM AND EVENTUALLY THE 12Z CMC APPEAR TO BE A LITTLE TOO STRONG. THE 12Z UKMET IS PERHAPS JUST A TAD TOO WEAK...AND SO BASED ON THIS...A BLEND OF THE 00Z GFS AND 12Z ECMWF WILL AGAIN BE PREFERRED. ...LOW PRESSURE APPROACHING SOUTH FL AND THE KEYS BY SUN... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: BELOW AVERAGE THE MODELS CONTINUE TO STRUGGLE WITH THE EVOLUTION OF 99L MOVING WEST-NORTHWEST IN BETWEEN THE NORTH COAST OF CUBA AND THE BAHAMAS...AND TOWARD THE GENERAL VICINITY OF SOUTH FL AND THE FL KEYS. THE 00Z NAM BECOMES THE SLOWEST SOLUTION AND ALSO SHOWS A BIT MORE DEVELOPMENT THAN THE MODEL CONSENSUS AS THE SYSTEM MOVES INTO THE EASTERN GULF OF MEXICO. THE GLOBAL MODELS ARE ALL FASTER AND FARTHER WEST...BUT THE 12Z CMC APPEARS TO BE TOO PROGRESSIVE. OVERALL...THE 00Z GFS/12Z UKMET AND 12Z ECMWF CLUSTER IN BETWEEN THE NAM AND CMC...BUT THE UKMET IS THE STRONGER OF THESE SOLUTIONS...WITH THE GFS AND ECMWF BOTH RATHER WEAK. THERE ARE SOME TIMING DIFFERENCES NOTED WITH THE GFS STILL A BIT FASTER THAN THE ECMWF AS WELL. THERE IS SIGNIFICANT ENSEMBLE MEMBER SPREAD WITH 99L...AND SO CONFIDENCE IS LIMITED. FOR NOW...WILL ATTEMPT TO TAKE A CONSENSUS OF THE WEAKER GFS/ECMWF SOLUTIONS GIVEN THE CURRENT LEVEL OF DISORGANIZATION TO THE SYSTEM. ...WEAK MID LEVEL LOW CENTER NEAR THE WESTERN GULF COAST ON SAT/SUN... PREFERENCE: NON-CMC CONSENSUS CONFIDENCE: AVERAGE THE 12Z UKMET REMAINS QUITE A BIT STRONGER WITH THIS FEATURE...BUT LACKS DETERMINISTIC SUPPORT FROM THE OTHER MODELS. THE LATEST GEFS MEAN AND ECENS MEAN SUPPORT A WEAKER/FLATTER SYSTEM AT LEAST FOR MASS FIELDS. WILL THUS LEAN TOWARD A NON-CMC CONSENSUS AT THIS TIME. ORRISON www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...