MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1234 AM EDT MON AUG 03 2015 VALID AUG 03/0000 UTC THRU AUG 06/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO DEGRADE THEIR SHORT RANGE FORECASTS. DEEP CYCLONE MOVING INTO BRITISH COLUMBIA TROUGH MOVES INTO THE NORTHWEST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z CANADIAN SHOWED A MORE SOUTHERLY 500 HPA CYCLONE MOVING ALONG THE US/CANADIAN BORDER -- ONE OF ITS USUAL BIASES. WITH THE REMAINDER OF THE GUIDANCE IN GOOD AGREEMENT WITH EACH OTHER AND THE 18Z GEFS/12Z ECMWF ENSEMBLE MEANS, FAVOR A COMPROMISE OF THE 12Z ECMWF/12Z UKMET/00Z NAM/00Z GFS WITH ABOVE AVERAGE CONFIDENCE. SHORTWAVE CROSSING THE ROCKIES/PLAINS SURFACE LOW CROSSING THE MS RIVER WED PM ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NAM/ECMWF COMPROMISE CONFIDENCE: AVERAGE THE 12Z UKMET ATTEMPTS TO FORM A WARM CORE CONVECTIVE CYCLONE WHICH DEEPENS A BIT AS IT MOVES INTO MO -- ONE OF ITS RECENT BIASES. THE 12Z CANADIAN IS PRONE TO SUCH FEEDBACK AS WELL, BUT ITS CENTRAL PRESSURE IS MORE RESPECTABLE. THE PROBLEM WITH THE CANADIAN IS THAT IT IS ON THE SLOW SIDE OF THE 12Z GLOBAL ENSEMBLE SPREAD. A COMPROMISE OF THE 00Z NAM/12Z CANADIAN SPLITS THE DIFFERENCE SEEN IN THE 18Z GEFS/12Z ECMWF ENSEMBLE MEAN SOLUTIONS, AND IS PREFERRED WITH AVERAGE CONFIDENCE. LOW PRESSURE MOVING FROM FL UP THE CAROLINA COAST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS CONFIDENCE: ABOVE AVERAGE THE 12Z CANADIAN/12Z UKMET ARE THE MOST BULLISH ON THIS SYSTEM -- WHICH IS THEIR BIAS. HOWEVER, THEY OUTPACE THE REMAINDER OF THE GUIDANCE HERE. FOR THE MOMENT, THE 00Z GFS APPEARS TO BE MOST FAVORED BY THE 12Z GLOBAL ENSEMBLE GUIDANCE, SO IT IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. DEEP CYCLONE MOVING THROUGH EASTERN CANADA TROUGH MOVING THROUGH THE NORTHEAST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THIS SYSTEM www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH