MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 213 PM EST WED NOV 26 2014 VALID NOV 26/1200 UTC THRU NOV 30/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION INCLUDING THE CANADIAN/UKMET/ECMWF ...LOW PRESSURE OVER THE NORTHERN PLAINS... WITH LITTLE RUN TO RUN CHANGE BY EITHER THE NCEP OR NON NCEP MODELS IN THE 12Z MODEL PRODUCTION CYCLES...AND THE MODELS CLUSTERING WELL...FEEL THAT EQUAL USE OF THE GUIDANCE WOULD WORK FINE. ...LOW PRESSURE FORMING ALONG THE EAST COAST... PREFERENCE: HALFWAY BETWEEN THE NAM AND GFS...ESSENTIALLY A MODEL CONSENSUS CONFIDENCE: AVERAGE BOTH THE NAM AND GFS INITIALIZED THE MID LEVEL HEIGHTS ABOUT 25 TO 30 METERS LOWER THAN OBSERVED AT KIAD...WITH 20 METER HEIGHT DIFFERENCES EXTENDING OVER TO WALLOPS ISLAND AND DOWN TO MOREHEAD CITY AND BACK TOWARDS JACKSONVILLE. THERE WERE SIMILAR DIFFERENCES BETWEEN THE RAOBS AND MODEL INITIALIZATION FROM BOTH THE NAM AND GFS OVER BERMUDA AS WELL. THE 12Z GUIDANCE IN GENERAL HAD GOOD CONTINUITY...WITH THE ECMWF MAINTAINING ITS STRONGER SOLN FROM 26/00Z RUN. THAT LEFT THE NAM/GFS ROUGHLY IN THE MIDDLE OF THE SPREAD. A SOLN SOMEWHERE BETWEEN THE SPEED OF THE WAVE AS SHOWN BY THE GFS/NAM AND A BIT TOWARDS THE AMPLITUDE OF THE ECMWF LOOKS TO HAVE THE BEST SUPPORT FROM THE ENSEMBLES. ...SHORTWAVE TROUGH INFLUENCING THE PACIFIC NORTHWEST AND NORTHERN ROCKIES THU/FRI... PREFERENCE: 26/12Z ECMWF CONFIDENCE: ABOVE AVERAGE GIVEN GOOD RUN TO RUN CONTINUITY...THE 12Z NAM MAINTAINED AN ALLIANCE IT FORMED WITH THE 12Z ECMWF. EARLY ON IN THE FORECAST...THERE IS GENERAL AGREEMENT WITH THE GFS AND CMC/UKMET. HOWEVER...AFTER 12Z ON FRIDAY...THE NAM BECAME TOO PROGRESSIVE WITH THE SOUTHERN STREAM ENTERING THE WEST COAST. CONSIDERING THAT THE 26/12Z ECMWF STILL LIES NEAR THE MIDDLE OF THE SOLUTION ENVELOPE AND HAS THE STRONGEST SUPPORT FROM THE ENSEMBLE MEANS...THE 12Z ECMWF WAS THE MOST STRONGLY PREFERRED OF THE OPERATIONAL MODELS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN