MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 139 PM EST MON JAN 6 2014 VALID JAN 6/1200 UTC THRU JAN 10/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z FINAL MODEL EVALUATION INCLUDING FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DON'T SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. SYSTEM APPROACHING THE PACIFIC NORTHWEST WEDNESDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 6Z GFS ENSEMBLE MEAN CONFIDENCE: WELL BELOW AVERAGE THERE REMAINS CONSIDERABLE SPREAD IN THE CURRENT MODEL SOLUTIONS REGARDING A STORM SYSTEM APPROACHING FROM THE NORTHEAST PACIFIC ON WEDNESDAY, WITH THE NAM BEING MUCH MORE PROGRESSIVE THAN THE MODEL CONSENSUS. THE 12Z ECMWF IS FLATTER WITH THE TROUGH AXIS, WHILE THE GFS SPLITS THE DIFFERENCE. THERE IS A LEAD SURFACE TROUGH NEARING THE COAST TUESDAY EVENING, AND MODEL AGREEMENT IS BETTER WITH THAT FEATURE, WITH THE NAM BEING THE MOST PROGRESSIVE AND THE CMC BEING THE WEAKEST. FOR RIGHT NOW, THE GFS ENSEMBLE MEAN FITS CLOSE TO THE MODEL AVERAGE, AND IS PROBABLY THE BEST WAY TO GO GIVEN THE CURRENT MODEL SPREAD WITH THE WEDNESDAY STORM SYSTEM. DISTURBANCE MOVING THROUGH THE WEST AND INTO THE PLAINS ON WEDNESDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z GFS/ECMWF CONFIDENCE: AVERAGE LOOKING AT THE 500MB HEIGHT PATTERN, THE CMC HAS BEEN DEEPER THAN THE REST OF THE MODEL GUIDANCE FOR ITS PAST TWO RUNS WITH RESPECT TO THE 500MB TROUGH, AND THE NAM APPEARS TOO FAR WEST WITH THE AXIS. BY THURSDAY, DIFFERENCES BEGIN TO AMPLIFY AND THE 12Z GFS SHOWS A MORE PROGRESSIVE TROUGH SIGNATURE THAN THE OTHER MODELS. AT THE SURFACE, A WELL-DEFINED INVERTED SURFACE TROUGH FORMS, WITH THE CMC MUCH FARTHER EAST AND MORE BROAD WITH THE AXIS, AND THE 12Z UKMET SHOWING A WEAKER FRONTAL SIGNATURE. POLAR VORTEX AND DEEPENING SURFACE LOW LIFTING NORTHWARD INTO EASTERN CANADA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE CURRENT MODEL GUIDANCE IS IN VERY GOOD AGREEMENT WITH THIS SYSTEM, BOTH AT THE SURFACE AND ALOFT. A GENERAL MODEL COMPROMISE IS PREFERRED TO SMOOTH OUT SMALL SCALE DIFFERENCES. www.wpc.ncep.noaa.gov/html/model2.shtml... HAMRICK