MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 140 PM EST THU NOV 13 2014 VALID NOV 13/1200 UTC THRU NOV 17/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...12Z ECMWF AVAILABLE THROUGH 78 HOURS/SUNDAY 18Z AT THE TIME OF THIS DISCUSSION'S ISSUANCE... 12Z MODEL EVALUATION WITH PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO DEGRADE ITS SHORT RANGE FORECASTS. BURGEONING TROUGH SLOWLY ENVELOPING NORTH AMERICA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/ECMWF/CANADIAN COMPROMISE CONFIDENCE: ABOVE AVERAGE THE 12Z NAM IS UNIQUELY SLOW IN MOVING A SHORTWAVE OUT OF THE PACIFIC NORTHWEST AND THROUGH THE INTER-MOUNTAIN WEST -- ONE OF ITS KNOWN BIASES. THE 12Z UKMET IS STRONGER/MORE CLOSED WITH A MID-LEVEL SYSTEM SWINGING THROUGH MANITOBA TOWARDS ND/MN SUNDAY, WHICH LEADS TO A SURFACE LOW/FRONTAL SOLUTION MORE NORTHWEST/SLOWER THAN THE REMAINDER OF THE GUIDANCE, LYING OUTSIDE THE 00Z GLOBAL ENSEMBLE SPREAD. THE 12Z NAM ALSO ADVERTISES SURFACE LOWS OFF THE EAST COAST SATURDAY AND SUNDAY SHOWN MUCH MORE WEAKLY ON THE OTHER DETERMINISTIC/GLOBAL ENSEMBLE GUIDANCE. THE OTHER SYSTEMS SURROUNDING THIS TROUGH (SHORTWAVE MOVING THROUGH THE SOUTHWEST AND SOUTHERN PLAINS FRIDAY/SATURDAY) SHOW GOOD AGREEMENT. THE 00Z ECMWF/12Z GEFS MEANS SUPPORT A 12Z GFS/12Z ECMWF/12Z CANADIAN COMPROMISE. SYSTEM LEAVING THE NORTHEAST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: HIGH 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