Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1156 PM EST Mon Jan 27 2020 Valid Jan 28/0000 UTC thru Jan 31/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preliminary Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Split flow trough crossing the Mountain West overnight and reaching the Southeast Wednesday night... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 28/00Z GFS and 27/12Z ECMWF/UKMET Confidence: Average The latest NCEP runs remains in decent agreement with the synoptic pattern...although the 28/00Z NAM was a weak and slow outlier by the end of day 3. The 27/12Z Canadian was clustered better with the NCEP guidance than it was in previous runs, but it also became an outlier by 00Z Thursday...leaving the UKMET in decent agreement with the NCEP guidance even if it was a tad slow. This leaves the previous model choices pretty much in tact with a combination of the 28/00Z GFS and the 27/12Z UKMET resulting in a good starting point for this system...with the NAM and CMC still not preferred. ...Progressive upper trough over the Pacific Northwest and amplifying into the Southern Plains Wednesday. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General Model Blend Confidence: Average Yet another in a series of systems moving in from the Pacific will move onshore later today and then dig into the Southwestern U.S. on Days 2/3. The models tended to handle the ridge building to the west of this system over the eastern North Pacific ocean and that results in a fairly consistent solution downstream as the trough drops southwest and amplifies near the base of the trough. The 28/00Z GFS and 17/12Z UKMET remain a bit more progressive similar to the 27/12Z ECMWF. Given the magnitude of the ridge building upstream, would tend to stay away from the solutions which are faster to move the system off the the east. Still think that trends suggest that a solution somewhere in the middle is the most probable outcome at this time through 12Z Friday. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Bann