MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1217 PM EDT FRI JUL 01 2016 VALID JUL 01/1200 UTC THRU JUL 05/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z GFS/NAM EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. SYSTEM MOVING THROUGH SOUTHWEST CANADA MONDAY CLOSED MID LEVEL SYSTEM OVER QUEBEC FRI INTO SUN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. A COMPROMISE OF THE AVAILABLE CONSENSUS IS PREFERRED TO DEAL WITH ANY LINGERING DETAIL ISSUES WITH ABOVE AVERAGE CONFIDENCE. SYSTEM MOVING ACROSS THE ROCKIES/CENTRAL PLAINS/OH VALLEY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z NAM REMAINS A STRONG OUTLIER WITH THIS SYSTEM; ITS USUAL BIAS 2-3 DAYS INTO THE FUTURE. PREFER A COMPROMISE OF THE REMAINING GUIDANCE (12Z GFS, 00Z UKMET, 00Z ECMWF, 00Z CANADIAN) WITH ABOVE AVERAGE CONFIDENCE. PATTERN ACROSS THE GREAT LAKES MONDAY/TUESDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 00Z CANADIAN ENDS UP WITH A SINGLE MID-LEVEL CYCLONE ACROSS CENTRAL QUEBEC LATE MONDAY, WHILE THE OTHER GUIDANCE SPLITS THE SYSTEM IN TWO. THE REPERCUSSIONS OF THE CANADIAN SOLUTION INCLUDE DISTINCT TROUGHING ACROSS SOUTHEAST CANADA/MICHIGAN THAT IS EITHER MUCH WEAKER, OR OUT OF PHASE, WITH THE REMAINDER OF THE GUIDANCE. THIS ISSUE DRAGS A SURFACE LOW INTO MI LATE MONDAY WHICH HAS NO 00Z GLOBAL ENSEMBLE SUPPORT. A COMPROMISE OF THE REMAINDER OF THE GUIDANCE (12Z GFS, 00Z ECMWF, 00Z UKMET, 12Z NAM) IS BEST HERE, AND PREFERRED WITH ABOVE AVERAGE CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH