MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1226 PM EDT SUN MAY 08 2016 VALID MAY 08/1200 UTC THRU MAY 12/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION WITH INITIAL PREFERENCES AND CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. ...CLOSED MID LEVEL LOW OVER THE NORTHERN ROCKIES OPENING UP OVER THE UPPER MS VALLEY ...LONG WAVE TROUGH OVER THE PACIFIC NORTHWEST CLOSES OFF OVER THE NORTHERN PLAINS... ...SURFACE LOW OVER THE NORTHERN PLAINS TUE/WED... PREFERENCE: 12Z NAM/12Z GFS/00Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z NAM WAS CLOSE TO THE MODEL CONSENSUS WITH BOTH THE MID LEVEL SYSTEM OVER THE NORTHERN ROCKIES OPENING UP INTO A LONG WAVE TROUGH OVER THE UPPER MS VALLEY/UPPER GREAT LAKES...AS WELL AS THE CLOSING MID LEVEL LOW OVER THE NORTHERN PLAINS TUE INTO WED. THE 12Z GFS IS FASTER THAN THE CONSENSUS WITH THE CLOSING MID LEVEL SYSTEM FOR TUE WED (NOT AS FAST AS THE 06Z GFS THOUGH)...BRINGING IT BACK CLOSER TO THE PACK BY WED. THE 12Z NAM WAS CLOSE TO THE CONSENSUS WITH THE PLACEMENT OF THE SURFACE LOW OVER ND TUE NIGHT/WED...WHILE THE 12Z GFS WAS EAST OF THE CONSENSUS POSITION (CLOSER TO THE 00Z GEFS MEAN). HOWEVER...BLENDING THE 12Z NAM/00Z ECMWF WITH THE NEWEST GFS SHOULD PRODUCE AN ACCEPTABLE LOW PLACEMENT BY LATE WED AFTERNOON. ...CLOSED MID LEVEL SYSTEM CROSSING NEW ENGLAND MON... PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE BOTH THE 12Z NAM AND 12Z GFS WERE CLOSE TO THE MODEL CONSENSUS WITH TIMING AND PLACEMENT OF THE THE CLOSED MID LEVEL SYSTEM AS IT CROSSES NEW ENGLAND MON...SO A GENERAL MODEL BLEND IS PREFERRED WITH THIS SYSTEM. ...CLOSED MID LEVEL SYSTEM APPROACHING HE PACIFIC NORTHWEST WED... PREFERENCE: NON 00Z UKMET BLEND CONFIDENCE: ABOVE AVERAGE BOTH THE 12Z NAM AND 12Z GFS WERE CLOSE TO THE MODEL CONSENSUS WITHE THE TIMING AND STRENGTH OF THE CLOSING MID LEVEL SYSTEM APPROACHING THE PACIFIC NORTHWEST TUE NIGHT INTO WED. THE 00Z UKMET REMAINS THE FASTEST SOLUTION WITH THE SYSTEM...SO IT WAS HELD OUT OF THE PREFERRED BLEND. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... HAYES