Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1124 PM EST Thu Dec 19 2019 Valid Dec 20/0000 UTC thru Dec 23/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preference and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 00Z GFS, 12Z ECMWF, 12Z ECMWF Ensemble Mean Confidence: Average The 00Z GFS has shown some important trends toward a slower progression of the large scale waves across the CONUS over the next few days. It now shows very close alignment to the 12Z ECMWF with the strong closed low along the Gulf Coast. Although it still pushes height falls eastward through the Intermountain West and Rockies faster in advance of the West Coast trough, the structure of the trough and position of embedded waves is now very close to the ECMWF. This still does yield slightly faster frontal timing on the West Coast in the GFS, and for details like this the preference would be a slight lean toward the ECMWF and ECMWF Ensemble Mean. Global models show relatively good consistency with the QPF patterns in the West despite some small differences in the timing and amplitude of the approaching trough. Therefore, the 12Z CMC and 12Z UKMET seem to offer reasonable forecasts in addition to the ECMWF and GFS in this region. The 00Z NAM is now slower than the consensus with the Gulf Coast system, and progresses the surface low further inland across Georgia. The 12Z CMC and UKMET also progress the surface low further inland than the GFS and ECMWF, and this affects the QPF distribution in those models. This has some ensemble support, but far less than the GFS and ECMWF. Considering all these factors, the model preference is for a blend of the GFS, ECMWF and ECMWF Ensemble Mean, which will provide good consistency with the previous preference for most areas of the CONUS, and has the greatest ensemble support at the moment. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers