MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1216 AM EDT SUN APR 03 2016 VALID APR 03/0000 UTC THRU APR 06/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. TROUGH MOVING FROM THE WEST INTO THE PLAINS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: ECMWF/GFS/CANADIAN COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE SMALL TIMING/DEPTH ISSUES ALOFT ARE TRANSLATING INTO MINIMAL ISSUES AT THE SURFACE WITH RESPECT TO THE SURFACE LOW. THE 00Z NAM LEAVES THE SAFETY OF THE 12Z GLOBAL ENSEMBLE CLUSTERING BY WEDNESDAY MORNING AND IS DEEMED TOO QUICK. OTHERWISE, THE 00Z GFS/12Z CANADIAN -- WHICH ARE THE SLOWEST/MOST AMPLIFIED ALOFT -- AGREE BEST WITH THE 12Z ECMWF/18Z GEFS MEAN SOLUTIONS. IN DEFERENCE TO MEDIUM RANGE, WILL INCLUDE THE 12Z ECMWF INTO THE MIX WITH IS ALSO WITHIN THE BETTER 12Z GLOBAL ENSEMBLE CLUSTERING, WHICH SHOULD TEMPER SOME OF THE TIMING ISSUE NOTED ALOFT. A COMPROMISE OF THE 12Z ECMWF/12Z CANADIAN/00Z GFS IS PREFERRED WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE. CLIPPER SYSTEM MOVING BY MIDWEST SUN/NORTHEAST MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/NAM/ECMWF COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z UKMET AND EVENTUALLY THE 12Z CANADIAN BECOME SLOW WITH THIS SYSTEM ALOFT AND AT THE SURFACE. THE 12Z GLOBAL ENSEMBLE CLUSTERING FAVORS THE QUICKER CONSENSUS WHICH BEFITS THE PROGRESSIVE FLOW PATTERN, SO A COMPROMISE OF THE 00Z GFS/00Z NAM/12Z ECMWF IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. SHORTWAVE MOVING ALONG THE GULF COAST SUN/MON UPPER TROUGH/CYCLONE DEPARTING NEW ENGLAND SUNDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ THE GUIDANCE IS IN GOOD AGREEMENT WITH THESE SYSTEMS, SO PREFER A GENERAL MODEL COMPROMISE TO DEAL WITH ANY LINGERING DETAIL ISSUES WITH ABOVE AVERAGE CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH