Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 242 AM EDT Mon Sep 24 2018 Valid Sep 24/0000 UTC thru Sep 27/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Final Model Evaluation...with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall preference for the entire CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 00Z GFS/00Z ECMWF Confidence: Slightly above average The models and ensemble means are indicating a transition to an amplified flow pattern across Canada and the northern half of the U.S. by the middle of the week as the northwestern U.S. upper trough builds and becomes firmly established over the northern plains and Upper Midwest. This trough will be bounded by two upper highs off both coasts of the U.S. as the synoptic scale pattern becomes more blocked. A few shortwave perturbations traversing the base of the trough will support surface lows and accompanying fronts during the short range forecast period. Most model guidance is in good agreement synoptically, however the 00Z CMC remains faster with the cold front crossing the Great Lakes and central plains on Tuesday, similar to its 12Z run. Regarding the disturbance approaching the Carolinas by midweek, the 00Z UKMET and to an extent the 00Z CMC are the slightly stronger solutions compared to the model consensus with the UKMET farthest west with the track. The consensus of the guidance besides the UKMET is that this energy should remain just off the East Coast and begin to recurve by the end of the forecast period out ahead of the cold front approaching the East Coast by late Wednesday. The UKMET is also faster with a surface low tracking southward from central Canada on Wednesday. Based on the latest model clustering, ensemble guidance and trends, the GFS and ECMWF are close to the model consensus and a blend of these solutions will be preferred at this time. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml D. Hamrick