Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1232 AM EDT Sun Mar 15 2020 Valid Mar 15/0000 UTC thru Mar 18/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Latest Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Deep upper trough/closed low impacting the West Coast... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average A deep upper trough and embedded closed low along the West Coast will gradually settle south over the next few days, and should begin to pivot somewhat off to the east by the middle of the week which will allow for more of an impact on the Great Basin and also the Southwest. The guidance is in good overall agreement with their mass fields, but with the 00Z GFS just a tad faster and farther east with the trough progression at the end of the period compared to the non-NCEP guidance. The model spread is still quite modest, and so a general model blend will be preferred with this system through the middle of the week. ...Trough crossing the Upper Midwest/Great Lakes by Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend Confidence: Above average A northern stream trough will cross the northern Plains, Upper Midwest and Great Lakes region by Tuesday, with an accompanying cold front sweep from the Midwest into the eastern U.S. This front will then sweep off the East Coast by Wednesday as the upper trough quickly exits the Great Lakes and crosses the Northeast. After about 48 hours, the 00Z GFS becomes a bit more progressive than the non-NCEP models with the trough progression. The latest GEFS mean and ECENS mean both favor a solution a tad less progressive. A general model blend should suffice through 48 hours, with a non-GFS blend thereafter. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Orrison