Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1132 PM EST Sun Feb 09 2020 Valid Feb 10/0000 UTC thru Feb 13/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Final Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Digging trough over the Great Basin/Southwest ejecting east toward the southern Plains by Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of ECMWF/GFS/CMC through 12.12Z, then ECMWF/GFS blend Confidence: Slightly above average Closed upper level low currently over southern California will slowly eject into the Southwest US and eventually the south-central Plains through the next 3 days. Through 48-60 hours, the ensemble and deterministic guidance is in above average agreement and has shown consistency the past several model cycles. Excluding the UKMET which was off in timing the progression of the system and the NAM which was a bit too deep, the ECMWF/GFS/CMC offer a fairly good approach that is similar to the ECENS/GEFS means. Toward Day 3, the GFS/GEFS becomes a bit faster compared to the ECMWF/ECENS, but overall a blend of the two solutions would yield a reasonable approach at this time. ...Shortwave crossing British Columbia Monday night... ...Energy dropping southeast across the northern Rockies Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend through 12.00Z; ECMWF/GFS blend thereafter Confidence: Slightly below average Two shortwaves will drop through the northern stream energy across the Northern Plains and Great Lakes region in the forecast period. The first wave swings through the northern Rockies Monday and splices off with some energy ejecting eastward toward the Great Lakes while another piece phases somewhat with the closed low over the Southwest US. Here the latest guidance has come into relatively good agreement with this idea such that a general model blend can be used through 12.00Z. Beyond that time frame, another shortwave trough quickly drops into the northern Rockies and becomes absorbed within the developing larger scale troughing over the central US by the end of Day 3. The CMC becomes too deep and slow over the Upper Midwest. While the GFS is a step ahead of its ensemble mean, there is reasonably good agreement and clustering such that the operational ECMWF/GFS seem like a good approach for Day 3 at this time. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor