MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1112 PM EST FRI JAN 02 2015 VALID JAN 03/0000 UTC THRU JAN 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 SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. SYSTEM IN THE NORTHERN PLAINS MONDAY NIGHT/MIDWEST TUE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 18Z GEFS MEAN/00Z GFS PARALLEL RUN CONFIDENCE: AVERAGE THE 00Z GFS/00Z NAM/12Z UKMET ARE FASTER AND FARTHER SOUTHEAST WITH THIS SYSTEM WHILE THE 12Z ECMWF IS THE SLOWEST. THE 00Z NAM/21Z SREF MEAN IS THE FARTHEST NORTHEAST AT THE SURFACE DUE TO THEIR SHORTWAVE TRACKING SOMEWHAT FARTHER NORTH. THE SHORTWAVE IS MOVING THROUGH BROAD TROUGHING, IMPLYING THAT A FASTER SOLUTION IS POSSIBLE. THERE HAS BEEN A DECIDED TREND TOWARDS THE STRONGER GFS SOLUTION FROM 02/00Z. HOWEVER, GFS/UKMET TEND TO BE QUICK WITH SYSTEMS AT THIS TIME RANGE WHILE THE ECMWF CAN BE SLOW. THE 18Z GEFS MEAN AND 00Z GFS PARALLEL RUN SPLIT THE DIFFERENCE WITH THIS SYSTEM, AND IS PREFERRED WITH AVERAGE CONFIDENCE. SYSTEM MOVING THROUGH THE EASTERN HALF OF THE NATION THROUGH SUN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE IS IN GOOD AGREEMENT WITH THE MAIN SYSTEM, AND THE PIECE OF ENERGY EJECTING THROUGH THE MIDWEST SATURDAY NIGHT. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH