MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 251 PM EDT WED MAY 14 2014 VALID MAY 14/1200 UTC THRU MAY 18/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION WITH PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. DEEP CYCLONE APPROACHING THE PACIFIC NORTHWEST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/ECMWF COMPROMISE CONFIDENCE: AVERAGE THE GUIDANCE SPREAD HAS INCREASED AMONGST THE 12Z GUIDANCE IN REGARDS TO THIS SYSTEM, WITH THE GFS/NAM NOW QUICKER THAN THE CANADIAN/UKMET GUIDANCE, WITH THE ECMWF IN BETWEEN. THERE ARE 2-3 DISCRETE SHORTWAVES/SMALL CLOSED LOWS MOVING OVER ITS NORTHERN SIDE OF THIS LARGER SYSTEM WHICH APPEAR TO BE URGING THE OVERALL SYSTEM EASTWARD. THE NAM, ECMWF, AND GFS HAVE ALL SPED UP THIS SYSTEM WHEN COMPARED TO THEIR 00Z RUNS. TO ACCOUNT FOR THIS, WILL SAFELY CHOOSE A 12Z ECMWF/12Z GFS COMPROMISE WITH CONFIDENCE NO BETTER THAN AVERAGE CONSIDERING THE POSSIBLE FUJIWARA/BINARY INTERACTIONS. SYSTEM MOVING TOWARDS ND SATURDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE AT 700 HPA, THE 12Z NAM SHOWS A CLOSED SYSTEM MOVING TOWARDS NORTH DAKOTA -- ITS USUAL BIAS WITH SYSTEMS ALOFT. THIS IS NOT SEEN IN ANY OF THE OTHER DETERMINISTIC GUIDANCE. ANY SYSTEMS MOVING OVER THE TOP OF THE WEAK RIDGE IN THE ROCKIES SHOULD HAVE MINIMAL AMPLITUDE. THE PREFERENCE IS FOR A NON-NAM COMPROMISE CONSIDERING ITS BIAS WITH ABOVE AVERAGE CONFIDENCE. SYSTEM MOVING THROUGH THE EAST ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE HANDLES THIS SYSTEM SIMILARLY. A GENERAL MODEL COMPROMISE IS PREFERRED TO DEAL WITH ANY LINGERING DETAIL ISSUES WITH ABOVE AVERAGE CONFIDENCE CONSIDERING THE MINIMAL MODEL SPREAD. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH