Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 225 AM EST Tue Dec 24 2019 Valid Dec 24/0000 UTC thru Dec 27/1200 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: Non-CMC blend Confidence: Above average ---07Z UPDATE--- No change to the preliminary preference. The 00Z CMC remains the most different relative to the other deterministic models with the closed low near Baja California on Thursday -- now slightly slower and further southwest. The other models remain in good agreement. ---PREVIOUS DISCUSSION--- Over the past couple model cycles, the deterministic models and ensembles have converged on a relatively similar forecast with decreasing spread. Some minor differences remain from a mass field perspective, but this has not led to substantial variation in the model QPFs. The 12Z CMC shows the greatest departures from model consensus, with the slowest progression of the closed low near Baja California on Thursday, and a stronger shortwave lifting through the Upper Midwest. This does lead to a few more notable differences in the QPF, particularly in the Upper Midwest with higher QPF. Therefore, the preference is for a broad multi-model blend that excludes the CMC. The remaining models (ECMWF, GFS, UKMET, NAM) are mostly well within the envelope of ensemble spread and have similar mass field forecasts. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers