MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1216 AM EDT WED OCT 14 2015 VALID OCT 14/0000 UTC THRU OCT 17/1200 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 SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. TROUGH APPROACHING THE NORTHWEST LATE FRIDAY NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NAM/GFS/ECMWF COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z UKMET WAS QUICKER IN MOVING THIS SYSTEM INTO THE NORTHWEST EARLY SATURDAY WHILE THE 12Z CANADIAN WAS THE SLOWEST -- THEIR USUAL BIASES. A COMPROMISE OF THE 00Z NAM/00Z GFS/12Z ECMWF FIT IN BEST WITH THE 12Z ECMWF/18Z GEFS ENSEMBLE MEAN SOLUTIONS, AND IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. SHORTWAVES AMPLIFYING TROUGH ACROSS GREAT LAKES THU/FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-UKMET COMPROMISE CONFIDENCE: ABOVE AVERAGE WHILE THE 00Z NAM WAS SHARPER THAN THE OTHER GUIDANCE WITH A SHORTWAVE CROSSING MI THURSDAY NIGHT, THE 12Z UKMET BECAME STRONG WITH A SYSTEM MOVING OUT OF ONTARIO TOWARDS THE NY/ONTARIO BORDER EARLY SATURDAY. THE 18Z GEFS/12Z ECMWF ENSEMBLE MEAN SOLUTIONS FAVOR A SOLUTION AWAY FROM THE UKMET HERE. TO DEAL WITH NAM ISSUES, A COMPROMISE OF THE 00Z GFS/00Z NAM/12Z CANADIAN/12Z ECMWF IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. TROUGH LIFTING OUT OF THE EAST THROUGH THURSDAY UPPER LOW MOVING INTO CALIFORNIA THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE IS IN GOOD AGREEMENT WITH THESE SYSTEMS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH