Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 141 AM EST Sat Nov 16 2019 Valid Nov 16/0000 UTC thru Nov 19/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...East of the Continental Divide... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-ECMWF blend Confidence: Average ---06Z UPDATE--- No significant change to the preliminary preference. The 00Z ECMWF did trend closer to the Northeast coastline with the surface low. Therefore, it could potentially be incorporated into a model blend with less weight applied now. ---PREVIOUS DISCUSSION--- The two significant synoptic features east of the Rockies are the developing low off the Southeast Atlantic coast, and the trough that will be digging into the Plains this weekend. Models have generally converged on the surface low evolution near the Carolinas prior to Sunday (17.12Z), but begin to diverge thereafter. This is due to variance with the strength of the upper level low over the Southeast, and the timing of the upstream wave. The 12Z ECMWF is notably slower with the upstream wave as compared to the other available models, and this contributes to a surface low track that is further offshore and weaker as compared to the 00Z NAM, 12Z CMC and 12Z UKMET. The 00Z GFS is slightly closer to the New England coast than the ECMWF, but not as far west as the other models. The preference is to go with a non-ECMWF blend as the strong consensus of most models is for faster timing of the upstream wave, and that should allow for a closer approach of the surface low to the coast than the ECMWF is depicting. This may also have some implications for light precipitation over the Great Lakes. ...West of the Continental Divide... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-GFS blend Confidence: Average ---06Z UPDATE--- No change to the preliminary preference. ---PREVIOUS DISCUSSION--- A strong trough will approach the Pacific Northwest on Monday. The 00Z GFS is further north with the core of the associated mid-upper level vorticity maximum than all the other available models, including the 18Z GEFS Mean. This leads to a northward displacement in the GFS precipitation fields. The preference is for a non-GFS blend along the West Coast. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers