MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1107 AM EST FRI DEC 23 2016 VALID DEC 23/1200 UTC THRU DEC 27/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ISSUES DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. CLOSED MID-LEVEL LOW DROPPING SOUTH OFF OF THE WEST COAST ON SUN ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: SOUTHWEST OF THE UKMET CONFIDENCE: AVERAGE THE GUIDANCE IS CONVERGING WITH THIS SYSTEM'S BEHAVIOR. CONSIDERING THE STRENGTH OF THE ANOMALOUS RIDGING TO ITS NORTHWEST, A MORE SOUTHWESTERLY SOLUTION SHOULD WORK OUT BEST, PARTICULARLY WITH A LACK OF A NEARBY KICKER. THIS IMPLIES THE ECMWF/CANADIAN ARE PROBABLY TOO NORTHEAST. HOWEVER, THE 12Z GFS/12Z NAM ARE SO FAR SOUTHWEST THAT THEY'RE SOUTH OF THE 06Z GEFS MEAN. PREFER A COMPROMISE OF THE AVAILABLE GUIDANCE HERE, WHICH IS A TOUCH SOUTHWEST OF THE 00Z UKMET, WITH AVERAGE CONFIDENCE. TROUGH DIGGING INTO THE WEST ON SAT CYCLONE MOVING INTO SD LATE SUNDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE WHILE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THE CYCLONE'S BEHAVIOR/DEPTH, THE 12Z NAM APPEARS SLOW WITH ITS TRAILING FRONT. PREFER A COMPROMISE OF THE 12Z GFS/00Z CANADIAN/00Z UKMET/00Z ECMWF CONSENSUS WITH ITS TRAILING FRONTAL BOUNDARY WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE. SHORTWAVE EMERGING INTO THE NORTHERN PLAINS LATE MONDAY SHORTWAVES MOVING BY NEW ENGLAND THROUGH SUNDAY MORNING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DIFFERENCES WITH THESE SYSTEMS REMAINS SMALL. A COMPROMISE OF THE AVAILABLE GUIDANCE IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH