Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1150 AM EST Wed Jan 15 2020 Valid Jan 15/1200 UTC thru Jan 19/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Exception: Non-CMC Day 3 western U.S. Confidence: Above average Two shortwave troughs are expected to track through the northern U.S. over the next 3 days, the first currently over the northern Plains and Upper Midwest with the other entering the Pacific NW and west coast later today. The first system now is showing above average clustering with the low track as it moves from the Great Lakes to the Gulf of Maine by Thursday morning. Here, differences between the deterministic guidance are minor and a general model blend is preferred. In the Day 2/3 period, a couple of shortwaves will move through the western US The first coming through Thursday night into Friday shows average to above average agreement with relatively high clustering between the deterministic guidance. Some timing differences develop with the secondary shortwave coming in later in the forecast period with the CMC being a bit of an outlier. Overall, the forecast preference is for a general model blend (higher weights toward the ECWMF/ECENS) with a non-CMC blend for the western U.S. on day 3. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor