Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 416 AM EDT Tue Mar 10 2020 Valid Mar 10/0000 UTC thru Mar 13/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Closed Low Affecting the Southwest... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above Average 08Z update: No significant changes noted with the rest of the 00Z guidance. The 00Z UKMET did trend more favorably toward the rest of the guidance, so will update the previous preference to go with a general model blend. A closed low well offshore southern California currently will be slow to move eastward and approach the coast over the next 24-36 hours. Over the last several model cycles, guidance has trended tighter and toward a solution favored by the 12 ECMWF deterministic run. However, much of the other deterministic guidance looks reasonable and well within the ensemble spread, outside of the UKMET which by day 2/3, pinches off more of the upper level energy to the southwest. By day 3, models all agree on the low wobbling toward the Baja with the UKMET lagging the rest of the deterministic models and outside the ensemble means. ...Northern Stream Flow... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend; exception non-GFS day 3 Confidence: Slightly Above Average Series of shortwave troughs will move within the progressive broad scale flow across the northern tier of the U.S., evolving into deeper troughing by day 3 over the Great Lakes region. In the large scale sense, the models show average to above average consistency and agreement with the pattern though there are more minor differences with some of the timing/progression of the systems. The exception is the 00Z GFS, with its evolution of a developing surface low over the Midwest and Great Lakes Thursday night. Its solution favors a stronger surface low tied to the northern shortwave trough whereas much of the other guidance, especially non-NCEP guidance, shows deepening surface low over the Great Lakes. Based on continuity, will favor a non-GFS blend on day 3 but a general model blend suffices for day 1/2. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor