MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 240 AM EDT FRI AUG 21 2015 VALID AUG 21/0000 UTC THRU AUG 24/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION WITH FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS APPEAR MINIMAL AND SHOULD NOT DEGRADE SHORT RANGE FORECASTS. COLD FRONT REACHING THE EAST COAST TODAY AND WEAKENING OVER THE WEEKEND ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THERE ARE NO SIGNIFICANT MASS FIELD DIFFERENCES WITH THIS SYSTEM. UPPER TROUGH/CYCLONE NEAR THE CENTRAL U.S./CANADIAN BORDER SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/ECMWF COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE THE GEFS/ECMWF/CMC ENSEMBLE GUIDANCE HAVE TRENDED SLIGHTLY SOUTH WITH THE UPPER TROUGH/CLOSED LOW AS IT TRACKS ALONG THE NRN PLAINS LATE SAT...IN THE DIRECTION OF THE DETERMINISTIC MODELS. ENSEMBLE SPAGHETTI HEIGHTS CONTINUE TO BE RELATIVELY WELL CLUSTERED AND SUPPORT A BLEND OF THE 00Z GFS AND 00Z ECMWF THROUGH 12Z/24. THE 00Z UKMET/CMC HAVE TRENDED TOWARD THE GFS/ECMWF COMPARED TO THEIR 12Z RUNS...BUT ARE CURRENTLY A BIT SOUTH OF THE ENSEMBLE MEANS REGARDING THE CLOSED LOW NEAR THE CANADIAN BORDER. MID-UPPER LEVEL DISTURBANCE OVER SOUTH TEXAS...WEAKENING INTO THE WEEKEND ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE SHOWS GOOD AGREEMENT WITH THIS SYSTEM. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... OTTO