MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1141 PM EST FRI JAN 09 2015 VALID JAN 10/0000 UTC THRU JAN 13/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...UPPER LEVEL TROUGHING OVER THE GREAT LAKES/NORTHEAST THROUGH SUN... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS ARE IN GOOD AGREEMENT WITH THE LARGE SCALE MASS FIELD DETAILS...SO A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...UPPER LEVEL TROUGH SHEARING EAST ACROSS THE SOUTHERN PLAINS/LOWER MS VALLEY... ...INVERTED SURFACE TROUGH NEAR THE WESTERN GULF COAST... PREFERENCE: NON-GEM CONSENSUS CONFIDENCE: ABOVE AVERAGE THE 12Z GEM IS MORE AGGRESSIVE IN THE LOW LEVELS OFF OF THE TEXAS COAST WITH LOW PRESSURE AND THE ASSOCIATED INVERTED TROUGH DEVELOPMENT. THIS COINCIDES WITH THE GEM HAVE A STRONGER SHORTWAVE TROUGH THAT EJECTS ACROSS THE SOUTHERN PLAINS VERSUS THE GLOBAL MODEL CONSENSUS. THE REMAINING MODELS ARE REASONABLY WELL CLUSTERED AT THE SURFACE AND ALOFT...SO WILL PREFER A NON-GEM CONSENSUS. ...SHORTWAVE ADVANCING INTO SOUTHERN CALIFORNIA/DESERT SOUTHWEST ON SUN... PREFERENCE: BLEND OF THE 00Z GFS/12Z UKMET AND 12Z ECMWF CONFIDENCE: AVERAGE THE 12Z GEM IS A SOMEWHAT MORE AMPLIFIED OUTLIER SOLN WITH THE SOUTHERN STREAM SHORTWAVE ADVANCING INTO SOUTHERN CALIFORNIA BY LATER SUN AND SUN NIGHT. THE 00Z NAM APPEARS TO BE A LITTLE FASTER THAN THE MULTI-MODEL CONSENSUS. THE 12Z UKMET/12Z ECMWF AND 00Z GFS ARE REASONABLY WELL CLUSTERED WITH THIS SYSTEM AS IT TRAVERSES THE SOUTHWEST THROUGH MON AND THIS CONSENSUS WILL BE PREFERRED. ...SHORTWAVE TROUGH REACHING THE NORTHWEST SUN NIGHT... ...ENERGY AMPLIFYING INTO THE GREAT BASIN ON MON... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE ALL OF THE MODELS SHOW A SHORTWAVE TROUGH CROSSING THE PACIFIC NORTHWEST SUN NIGHT AND THEN DIGGING INTO THE GREAT BASIN ON MON. THE 12Z GEM OVERALL IS THE WEAKEST SOLN WITH THIS SYSTEM. THE 12Z UKMET IS A LITTLE MORE AGGRESSIVE WITH ITS HEIGHT FALLS BY MON ACROSS THE GREAT BASIN. THE 00Z NAM/00Z GFS AND 12Z ECMWF ARE A LITTLE SLOWER AND LESS AGGRESSIVE VERSUS THE UKMET...BUT ARE ALL STRONGER THAN THE GEM. THE BETTER MODEL CLUSTERING FAVORS A BLEND OF THE 00Z GFS AND 12Z ECMWF AND THESE SOLNS ARE SUPPORTED BY THE GEFS MEAN AND ECENS MEAN. ...POSITIVELY TILTED TROUGH IMPACTING THE UPPER MIDWEST/GREAT LAKES... PREFERENCE: BLEND OF THE 00Z GFS/12Z UKMET AND 12Z ECMWF CONFIDENCE: AVERAGE THE MODELS SHOW A POSITIVELY TILTED TROUGH EXTENDING FROM HUDSON BAY SOUTHWEST DOWN TO THE UPPER MIDWEST ON SUN THAT WILL MOVE EAST THROUGH THE GREAT LAKES ON MON. THE 12Z GEM IS A MORE AMPLIFIED OUTLIER SOLN WITH THIS SYS. THE 00Z NAM OVERALL APPEARS TO BE A BIT WEAKER THAN THE CONSENSUS. THE 00Z GFS...12Z UKMET AND 12Z ECMWF TEND TO CLUSTER TOGETHER THE BEST OVERALL AND HAVE STRONGER ENSEMBLE SUPPORT THROUGH THE 18Z GEFS MEAN AND 12Z ECENS MEAN. A BLEND OF THE GFS/UKMET AND ECMWF WILL BE PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON