MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1124 PM EST MON JAN 12 2015 VALID JAN 13/0000 UTC THRU JAN 16/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...NORTHERN STREAM TROUGH CROSSING THE UPPER MIDWEST TO NEW ENGLAND THROUGH TUESDAY... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE A SHORTWAVE TROUGH IS FORECAST TO SWING FROM THE GREAT LAKES THROUGH NEW ENGLAND THROUGH TUESDAY. THE MODELS ARE NOW IN GOOD AGREEMENT WITH THE TIMING AND DEPTH OF THIS SYSTEM AND SO A GENERAL MODEL COMPROMISE IS PREFERRED. ...NORTHERN STREAM ENERGY CROSSING THE MIDWEST/GREAT LAKES/OHIO VALLEY AND NORTHEAST THROUGH THURSDAY... PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF CONFIDENCE: AVERAGE A COUPLE OF SHORTWAVE IMPULSES WILL BE IMPACTING THE REGION OVER THE NEXT COUPLE OF DAYS. ONE SHORTWAVE CROSSES THE MIDWEST AND OHIO VALLEY TUESDAY AND WEDNESDAY. THE 00Z NAM BECOMES A BIT SHARPER THAN ANY OTHER MODEL WITH THIS FEATURE. THE 12Z UKMET IS A BIT WEAKER THAN THE CONSENSUS AND FASTER. A SECOND SHORTWAVE WILL CROSS THE REGION AND DIG INTO THE MID-ATLANTIC AND NORTHEAST THROUGH THURSDAY. THE 12Z UKMET IS A BIT MORE PROGRESSIVE THAN THE OTHER MODELS WITH THE SECOND SHORTWAVE AS WELL. THE STRONGER MODEL CLUSTERING GENERALLY FAVORS THE 00Z GFS AND 12Z ECMWF AND IS REASONABLY WELL SUPPORTED BY THE ENSEMBLE MEANS...SO A GFS/ECMWF COMPROMISE IS FAVORED. ...SHORTWAVE EJECTING OUT OF THE LOWER MISSISSIPPI VALLEY... ...ENERGY CROSSING THE SOUTHERN MID-ATLANTIC REGION... PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF CONFIDENCE: ABOVE AVERAGE A SHORTWAVE WILL SHEAR EAST OUT OF THE LOWER MS VALLEY REGION ON TUESDAY AND EXIT THE SOUTHERN MID-ATLANTIC REGION EARLY WEDNESDAY. THE 00Z NAM AND 12Z GEM ARE JUST A TAD SHARPER WITH THIS FEATURE COMPARED TO THE 00Z GFS/12Z ECMWF AND 12Z UKMET. THE NAM AND GEM ALSO FAVOR A SLIGHTLY STRONGER SURFACE REFLECTION JUST OFF THE MID-ATLANTIC COAST TUESDAY NIGHT AND EARLY WEDNESDAY. BETTER CONTINUITY IS FOUND WITH THE GFS AND ECMWF SOLUTIONS FOR THIS LOW AMPLITUDE FEATURE...AND A BLEND OF THESE SOLUTIONS WILL BE PREFERRED. ...SHORTWAVE TROUGH OVER THE FOUR CORNERS REGION... PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF CONFIDENCE: AVERAGE THE 00Z NAM/12Z GEM AND 12Z UKMET HANG ONTO TO MORE ENERGY OVER THE FOUR CORNERS REGION THROUGH WEDNESDAY AND THURSDAY VERSUS THE 00Z GFS AND 12Z ECMWF WHICH AGREE IN TAKING THE LEFTOVER CLOSED LOW AND ASSOCIATED TROUGH EAST OUT ACROSS THE SOUTHERN PLAINS AND TOWARD THE LOWER MS VALLEY. THE ENERGY SHOULD SHEAR OUT BY THE END OF THE PERIOD GIVEN THE MORE DOMINANT NORTHERN STREAM FLOW. THE LATEST GEFS MEAN AND ECENS MEAN FAVOR THE GFS/ECMWF SOLUTIONS AND SO A BLEND OF THESE SOLUTIONS WILL BE PREFERRED. ...SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST BY EARLY THURSDAY... PREFERENCE: BLEND OF THE 00Z GFS/12Z ECMWF CONFIDENCE: AVERAGE THE MODELS INDICATE A SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST BY EARLY THURSDAY. THE 00Z NAM IS A SLOWER AND STRONGER OUTLIER SOLUTION WITH THIS ENERGY AS IT ARRIVES INTO THE NORTHWEST. THE 12Z UKMET AND 12Z GEM ARE WEAKER AND ARE THE FASTEST SOLUTIONS. THE 00Z GFS AND 12Z ECMWF SPLIT THE DIFFERENCE AND CLUSTER WELL WITH TIMING AND DEPTH THROUGH THURSDAY AND ALSO DOWNSTREAM FRIDAY AS THE ENERGY ADVANCES OUT INTO THE HIGH PLAINS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON