MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 231 AM EDT WED JUL 01 2015 VALID JUL 01/0000 UTC THRU JUL 04/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION WITH PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. DEEP CYCLONE MOVING THROUGH WESTERN CANADA FRI/SAT FRONT DROPPING INTO MONTANA FRIDAY NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THIS SYSTEM. UPPER LOW/WEAKNESS ACROSS CENTRAL MEXICO ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/ECMWF/CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 00Z UKMET BECOMES A WEAK OUTLIER WITH THIS SYSTEM WHILE THE 00Z NAM IS THE STRONGEST. A COMPROMISE OF THE 00Z GFS/00Z ECMWF/00Z CANADIAN APPEARS BEST HERE, AND IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. SECOND WAVE MOVING FROM KS THROUGH THE MID-SOUTH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: ECMWF CONFIDENCE: AVERAGE THE 00Z GFS/TO SOME DEGREE THE 21Z SREF MEAN WERE THE MOST AMPLIFIED ALOFT WITH THIS SYSTEM (SIMILAR TO THE 29/12Z ECMWF RUN) AND BROUGHT THE LOW FARTHEST TO THE NORTH ALONG THE OH RIVER. THIS IS A PROBLEM AS A WEAK SHORTWAVE UPSTREAM ACROSS ALBERTA LATE THURSDAY AND MT/ND LATE FRIDAY COULD PREVENT A MORE AMPLIFIED SOLUTION ALOFT DOWNSTREAM. THE 00Z UKMET WAS THE WEAKEST ALOFT AND THE FARTHEST SOUTH WITH THE SURFACE LOW MOVING IT INTO TN. THE 00Z ECMWF WAS SIMILAR TO ITS OLD ENSEMBLE MEAN SOLUTION WHICH IS IN THE MIDDLE OF THE GUIDANCE SPREAD, SO IT IS PREFERRED WITH AVERAGE CONFIDENCE. FIRST WEAK WAVE MOVING BY THE VA CAPES FRIDAY MORNING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: ECMWF/UKMET COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE 00Z GFS WAS TOO WEAK WITH ITS PARENT SHORTWAVE, WHICH LED TO A WEAKER AND MORE DEPRESSED SURFACE SOLUTION. THE 00Z CANADIAN LOOKS LIKE THE GFS AT THE SURFACE DESPITE ITS REASONABLE SOLUTION ALOFT. A COMPROMISE OF THE 00Z ECMWF/00Z UKMET IS SUPPORTED BEST BY THE 12Z GLOBAL ENSEMBLE LOW CLUSTERING AND IS PREFERRED WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH