Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 145 PM EST Sun Feb 02 2020 Valid Feb 02/1200 UTC thru Feb 06/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation with Latest Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ ...Deep longwave trough evolving over the Western U.S. this week... ...Surface wave activity developing over the lower/mid MS Valley... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ Preference: Blend of the 12Z UKMET/ECMWF and 12Z GEFS/00Z ECENS means Confidence: Slightly above average The 12Z GFS and to an extent the 12Z NAM just as it in previous runs continue to be more progressive with the evolution of the deep longwave trough evolution over the Western and Central U.S. over the next few days. This drives a more progressive surface wave evolution over the lower MS Valley and eventually the Gulf Coast states by late Wednesday, with the GFS in particular outrunning the guidance. The ensemble means led by the 12Z GEFS and 00Z ECENS suites favor the less progressive consensus led by the 12Z non-NCEP (UKMET, CMC and ECMWF) solutions. However, the CMC has trended notably slower and is the slowest solution. Accounting for the slower CMC, and the faster NAM/GFS, would suggest favoring a solution toward the UKMET/ECMWF and the latest ensemble means. ...Northern stream energy traversing the northern Plains/Great Lakes... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ Preference: Blend of the 12Z ECMWF/GEFS mean and 00Z ECENS mean Confidence: Slightly above average There are subtle differences with respect to a northern stream trough clipping the northern Plains, Great Lakes and northern New England through Wednesday, but the UKMET overall appears a bit too progressive with this feature. Additional northern stream energy by late Wednesday will be also crossing southern Canada and digging across the northern Plains. The non-NCEP models generally have better support from the GEFS/ECENS means with this energy, and overall with the lead energy outside of the UKMET. So, with the NAM/GFS camp relatively out of tolerance, the preference will be toward a blend of the 12Z ECMWF/GEFS mean and 00Z ECENS mean with the northern stream energy going through midweek. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Orrison