Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1155 PM EST Thu Nov 14 2019 Valid Nov 15/0000 UTC thru Nov 18/1200 UTC ..See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 00Z NAM, GFS; 12Z ECMWF NAM excluded on Day 3 (after 17.12Z) Confidence: Average The most substantial model differences are related to a strong upper level low approaching the Southeast Atlantic coast and related cyclogenesis off the coast of the Carolinas. Over the remainder of the CONUS, model forecast precipitation is either very limited or in fairly good agreement in areas of stronger orographic ascent in the Pacific Northwest. For the Southeast, the 00Z NAM continues to produce a surface low closer to the coast, yielding higher QPF over land areas. The only relatively comparable deterministic model forecast is from the 12Z CMC, which has its surface low positioned slightly further offshore. The remaining models are slower and further offshore, and have less QPF over land areas. The trend on the past several runs of the GFS has been slower and there is better ensemble support for a low position further offshore. Nevertheless, given the strength of the upper level low approaching the coast and the proximity of the sea-surface temperature gradient to the coast, a scenario closer to the NAM is not unreasonable. The model preference is for a blend of the NAM, GFS and ECMWF to place greater weight on an offshore scenario, but incorporate some potential for a closer approach to the coast. By Sunday, the NAM begins to diverge more significantly from other models, drawing the surface low north toward New England, while the remaining models have a track much further southeast. This is related to differences with an upstream shortwave digging through the Midwest, and the initial position of the surface low being further northwest than the remaining models. The ensemble support for such a scenario is even more limited, and as a result the NAM is excluded from the model preference after 12Z Sunday. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers