MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1123 PM EST WED NOV 05 2014 VALID NOV 06/0000 UTC THRU NOV 09/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ================================================== 00Z NAM/GFS EVALUATION AND PRELIMINARY PREFERENCES ================================================== NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT. ================================================== ...GREAT LAKES TROUGH LEADING TO CYCLOGENESIS IN NEW ENGLAND... PREFERENCE: BLEND OF 00Z GFS WITH 12Z ECMWF/UKMET MODEL MASS FIELDS AND THERMAL FIELDS ARE SIMILAR THROUGH DAY 1...07/12Z. THEREAFTER THE GFS SPEEDS UP A BIT RELATIVE TO THE NAM/ECMWF/UKMET. THE NAM APPEARS SOMEWHAT BROAD WITH ITS LOW LEVEL CYCLONE AND NOT QUITE AS DEEP AS CONSENSUS. THE ONLY SEEMING OUTLIER WAS THE 12Z CANADIAN WITH A WEAKER LOW TRACKING FARTHER EAST. JUDGING PARTIALLY BY THEIR PRECIPITATION OUTPUT...THE GFS/ECMWF/UKMET COMPRISE A BLEND THAT IS REPRESENTATIVE OF CONSENSUS. ...ADJUSTMENTS LEADING TO AN AMPLIFIED WESTERN RIDGE/EASTERN TROUGH... PREFERENCE: BLEND OF 00Z GFS/12Z ECMWF AS THE PATTERN AMPLIFIES FROM THE EASTERN PACIFIC INTO WESTERN NORTH AMERICA...A LOOSELY DEFINED FULL LATITUDE TROUGH IS SET TO DEVELOP IN EASTERN NORTH AMERICA OWING TO A NUMBER OF INDIVIDUAL DISTURBANCES. NAMELY...A SHORTWAVE TOPPING THE RIDGE IN THE NORTHERN ROCKIES THURSDAY NIGHT WILL EVENTUALLY DIVE SOUTHEASTWARD AND PHASE WITH THE OPENING LOW THAT WILL BE DRIFTING INTO THE GULF OF MEXICO. AT THE SAME TIME...A DEEP LOW IS FORECAST TO DROP TOWARD ONTARIO. RUN TO RUN CONSISTENCY AND ENSEMBLE SUPPORT LEADS US TO FAVOR THE GFS AND ECMWF. OVER MULTIPLE CYCLES THE GEFS MEAN AND ECMWF ENSEMBLE MEAN HAVE BEEN ADJUSTING TOWARD ONE ANOTHER. THE GEFS MEAN HAS ADJUSTED MORE SIGNIFICANTLY...HAVING STARTED TOO FAR NORTH WITH THE LOW IN CANADA. THE OPERATIONAL GFS APPEARS TO HAVE CAUGHT UP TO THE ECMWF CAMP MORE QUICKLY THAN THE GEFS MEAN. ...CLOSED LOW SPINNING OVER CENTRAL MEXICO... PREFERENCE: BLEND OF 12Z GFS/ECMWF THE GFS/ECMWF ARE JUST SLIGHTLY FASTER THAN THE REST OF THE OPERATIONAL MODELS IN OPENING THIS LOW AND PUSHING AN OPEN WAVE TOWARD FLORIDA AND THE SOUTHEAST STATES. ENERGETIC FLOW DROPPING THROUGH THE CENTRAL U.S. SHOULD BE IN A GOOD POSITION TO KICK THIS WAVE EASTWARD...AND GIVEN THE ENSEMBLE SUPPORT FOR THE GFS/ECMWF...WE CAN RECOMMEND THOSE MODELS BE USED HERE. ...NEXT SHORTWAVE APPROACHING THE PACIFIC NORTHWEST BY SUNDAY MORNING... PREFERENCE: BLEND OF 00Z NAM/GFS UPSTREAM AMPLIFICATION IS EXPECTED...OWING TO A STRONG ALEUTIANS SYSTEM. SPLIT FLOW OVER THE GULF OF ALASKA SHOULD YIELD CLOSED LOW FORMATION OUT AT 145-150 WEST BY 09/12Z...WHILE A NORTHERN STREAM SHORTWAVE COMES INTO BRITISH COLUMBIA AND WASHINGTON STATE AROUND THE SAME TIME. SPAGHETTI PLOTS SHOW THE ECMWF AND ECMWF ENSEMBLE MEAN TO HAVE BEEN LACKING CONSISTENCY WITH THESE MEDIUM WAVELENGTH SYSTEMS. THE GFS/GEFS...CANADIAN MODEL AND ASSOCIATED ENSEMBLE...AND THE UKMET HAVE ALL SHOWN SIMILAR TRENDS TO ONE ANOTHER. WPC WILL SIDE WITH THE MAJORITY CONSENSUS HERE...ESPECIALLY AS THE UPSTREAM AMPLIFICATION WOULD SUPPORT THE MORE WESTERLY CLOSED LOW...AROUND 150 WEST...SEEN IN THE RECENT NAM/GFS/GEFS RUNS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BURKE