MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1216 AM EDT SAT AUG 23 2014 VALID AUG 23/0000 UTC THRU AUG 26/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...UPPER TROUGHING MOVING THROUGH THE NORTHEAST... ...COLD FRONT SINKING SWD THROUGH THE EAST COAST STATES... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE DETAILS OF THE TROUGH EXITING THE NORTHEAST OVER THE NEXT COUPLE OF DAYS. A GENERAL MODEL COMPROMISE WILL BE PREFERRED BASED ON THE LARGER SCALE AGREEMENT. ...WEAKENING MID LEVEL DISTURBANCE LIFTING NEWD FROM THE SOUTHWEST... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE NAM HAS COME INTO BETTER AGREEMENT WITH THE OTHER MODELS WITH THE DETAILS OF THE EXITING SRN STREAM SHORTWAVE TROUGH OVER THE SOUTHWEST. A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...UPPER TROUGHING/CLOSED LOW ADVANCING THROUGH THE WEST THROUGH SAT... ...SURFACE LOW MOVING THROUGH THE NORTHERN PLAINS AND INTO CANADA... PREFERENCE: BLEND OF THE 12Z UKMET/12Z GEM AND 12Z ECMWF CONFIDENCE: AVERAGE THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE DEEP TROUGH/CLOSED LOW THAT WILL BE EXITING THE WESTERN U.S. OVER THE NEXT COUPLE OF DAYS AND TRAVERSING THE NRN PLAINS AND SRN CANADA. ALL OF THE MODELS INDICATE THAT SFC LOW PRESSURE DEVELOPING OVER THE CNTRL PLAINS ATTM WILL LIFT NNEWD THROUGH THE PERIOD AND INTENSIFY WHILE MOVING INTO SRN CANADA BY SUN AND MON. THE 00Z NAM AT TIMES APPEARS A LITTLE SLOW TO LIFT ITS LOW CENTER NWD THROUGH THE NRN PLAINS...WHEREAS THE 00Z GFS IS NOTED TO BE TUCKING ITS SFC LOW PRESSURE AREA A LITTLE TOO FAR BACK TO THE WEST. THE 00Z GFS BECOMES SLOW IN TIME TO ADVANCE THE ENERGY ALOFT EASTWARD ACROSS SRN CANADA. OVERALL...THERE IS STRONGER MODEL CLUSTERING COMPARED TO PREV RUNS...BUT WILL STILL FAVOR A NON-NCEP CONSENSUS ATTM. ...ADDITIONAL SHORTWAVE ENERGY DIGGING INTO THE NORTHWEST BY SUN AND MON... PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF AND 12Z GEM CONFIDENCE: AVERAGE THE 00Z NAM IS A STRONGER OUTLIER WITH ITS SHORTWAVE ENERGY THAT AMPLIFIES OVER THE WEST BY MON AND TUES. THE 12Z UKMET MEANWHILE SEEMS TO BE DROPPING ENERGY TOO FAR SOUTH THROUGH THE GREAT BASIN. THE STRONGER MODEL CLUSTERING FAVORS A BLEND OF THE 00Z GFS/12Z ECMWF AND 12Z GEM AND THAT WILL BE THE PREFERENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON