MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1220 AM EDT MON SEP 26 2016 VALID SEP 26/0000 UTC THRU SEP 29/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. DEEP CYCLONE DROPPING TOWARDS OH VALLEY SECONDARY ENERGY IN SOUTHEAST CANADA FRONTAL WAVE MOVING OFFSHORE EASTERN SEABOARD ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GFS/CANADIAN/UKMET BLEND CONFIDENCE: NO BETTER THAN AVERAGE THERE HAS BEEN SOME SOUTHWEST ADJUSTMENT SEEN IN MOST OF THE GUIDANCE WITH THE MAIN UPPER LOW SINCE THIS TIME YESTERDAY, IN THE DIRECTION OF THE 12Z ECMWF/00Z NAM SOLUTIONS. A BUILDING UPSTREAM RIDGE IN THE PLAINS COULD ALLOW FOR A MORE SOUTHERN SOLUTION. THE 12Z ECMWF ENSEMBLE MEAN SOLUTION IS SOUTH OF THE 18Z GEFS MEAN, BUT NOT TO THE DEGREE OF THE 12Z ECMWF. FOR THE MOMENT, PREFER A SOLUTION BETWEEN THE MEANS, WHICH WOULD BE A COMBINATION OF THE 00Z GFS/12Z CANADIAN/12Z UKMET, WITH CONFIDENCE NO BETTER THAN AVERAGE. THIS PREFERENCE APPLIES TO THE ENERGY NEAR QUEBEC/NORTHWEST OF MAINE, WHICH SHOULD BE WEAK AND QUASI-STATIONARY. SHOULD THERE BE ANY FURTHER SOUTHWARD TRENDS IN THE 00Z GUIDANCE, WHICH IS POSSIBLE IN THIS FLOW PATTERN, ADDITIONAL ADJUSTMENT IN THE DIRECTION OF THE ECMWF MAY BE REQUIRED ACROSS THE OHIO VALLEY/MID-ATLANTIC STATES/SOUTHEAST. STAY TUNED. UPPER TROUGH AMPLIFYING OFFSHORE THE NORTHWEST WED UPPER LOW SHEARING NORTHWARD INTO THE GREAT BASIN SYSTEM CLIPPING THE PACIFIC NORTHWEST MON NIGHT WEAKENING UPPER TROUGH NEAR FL MONDAY AND TUESDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. PREFER A COMPROMISE OF THE AVAILABLE GUIDANCE TO DEAL WITH DETAIL ISSUES, WITH ABOVE AVERAGE CONFIDENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ROTH