MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 232 PM EDT WED SEP 10 2014 VALID SEP 10/1200 UTC THRU SEP 14/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM AND THE ECMWF ...SURFACE LOW LIFTING THROUGH THE GREAT LAKES LATER TODAY... ...TRAILING COLD FRONT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE TRACK OF SURFACE LOW PRESSURE WHICH WILL BE EXITING ACROSS THE GREAT LAKES REGION BY LATER TODAY AND THEN RAPIDLY MOVING ACROSS ERN CANADA THE NEXT COUPLE OF DAYS. A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...SHORTWAVE TRACKING FROM THE NORTHERN ROCKIES TO THE GREAT LAKES BY SAT... ...WEAK SURFACE WAVE LIFTING UP INTO THE OHIO VALLEY... PREFERENCE: BLEND OF THE 12Z ECMWF AND 12Z GEM CONFIDENCE: SLIGHTLY BELOW AVERAGE A SHORTWAVE TROUGH DIGGING SEWD THROUGH SRN ALBERTA THIS MORNING WILL DROP DOWN ACROSS CNTRL/ERN MT BY EARLY THURS. THEREAFTER THE ENERGY WILL MOVE EASTWARD AND REACH THE GRT LAKES REGION FRI NIGHT WHILE CONTINUING TO AMPLIFY. THE ENERGY WILL BE IN SUFFICIENTLY CLOSE PROXIMITY TO THE BAROCLINIC ZONE OVER THE GULF COAST AND SOUTHEAST FOR A WAVE OF LOW PRESSURE TO DEVELOP ALONG THIS BNDRY AND THEN LIFT NEWD INTO THE OH VLY ON SAT. THE 12Z GFS AND TO A LESSER EXTENT THE 12Z NAM ARE THE FASTEST SOLNS WITH THE DIGGING SHORTWAVE TROUGH...AND BOTH OF THESE MODELS INDICATE MUCH WEAKER SFC LOW REFLECTIONS OVER THE OH/TN VLYS. THE 12Z GEM AND 12Z ECMWF ARE SLOWER AND MORE AMPLIFIED WITH THE ENERGY FRI AND SAT...WITH THE 12Z UKMET THE SLOWEST. THE LATEST GEFS MEAN IS A TAD SLOWER THAN THE 12Z GFS AND THE ECENS MEAN IS SLOWER AS WELL LIKE THE ECMWF/GEM CAMP. WILL FAVOR A RELATIVELY SLOWER SOLN IN LINE WITH A BLEND OF THE ECMWF/GEM SOLNS GIVEN STRONGER ENSEMBLE SUPPORT. ...SHORTWAVE TROUGH DIGGING TOWARD THE NORTHERN PLAINS ON SAT... PREFERENCE: NON-GFS CONSENSUS CONFIDENCE: AVERAGE THE NEXT IN A SERIES OF NRN STREAM TROUGHS WILL DIG TWD THE NRN PLAINS BY SAT FROM SWRN CANADA. THE 12Z GFS GRADUALLY BECOMES SLIGHTLY WEAKER THAN THE GLOBAL MODEL CONSENSUS ALOFT WITH THIS SYS...BUT ALL OF THE MODELS NOW SUPPORT THE IDEA OF AT LEAST A WEAK CLIPPER TYPE LOW CENTER DEVELOPING OVER THE NRN PLAINS BY SAT. WILL PREFER A NON-GFS CONSENSUS WITH THIS SYS GIVEN REASONABLY GOOD MASS FIELD AGREEMENT SEEN OTHERWISE. ...WEAK EASTERLY WAVE TRACKING APPROACHING SOUTH TEXAS BY FRI.... PREFERENCE: NON-UKMET CONSENSUS CONFIDENCE: AVERAGE ALL OF THE MODELS SHOW AN EASTERLY WAVE MOVING INTO SRN TX BY FRI. THE 12Z UKMET IS BIT STRONGER AND SLOWER THAN THE MULTI-MODEL CONSENSUS WITH THIS SYS. WILL PREFER A NON-UKMET CONSENSUS. ...WEAK EASTERLY WAVE TRACKING APPROACHING SOUTH FLORIDA BY SAT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: AVERAGE ALL OF THE MODELS SHOW AN EASTERLY WAVE MOVING INTO SRN FL BY SAT. THERE IS SUFFICIENT MASS FIELD AGREEMENT AT LEAST ON THE LARGER SCALE FOR A GENERAL MODEL COMPROMISE TO BE SUGGESTED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON