Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 222 PM EST Sat Nov 16 2019 Valid Nov 16/1200 UTC thru Nov 20/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Model Evaluation with Preferences and Forecast Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...East of the Continental Divide... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-UKMET blend Confidence: Average 19Z Update: The 12Z UKMET and CMC remain the western solutions with the East Coast storm system, with little changes from the prior run. Meanwhile the ECMWF continued to be a bit of an eastern solution and still remains in agreement with the GFS. A non-UKMET blend is still the preferred blend at this time. ---previous discussion--- Two mid/upper level features of note that will be the key players with the track/evolution of a surface low along the East Coast through the next few days. Current closed mid/upper level low off the Southeast U.S. coast will open up and become absorbed into the deepening longwave trough over the eastern 2/3 of the CONUS. This is due to a fast moving shortwave trough that becomes negatively tilted by Monday over the Ohio Valley and Mid-Atlantic. The latest forecast guidance has come into better agreement through 48 hours (18.12Z) but there remains some key differences for Day 3. The most recent GFS trended toward the 00Z ECMWF operational run and now both of these models are the more offshore solutions. The 00Z UKMET is the furthest west and the 12Z NAM also is a western solution. The 00Z CMC lies near the middle of these solutions, but becomes too slow after 60 hours compared to the rest of the model guidance. The 12Z GFS and 00Z ECMWF are left/west of their ensemble means and overall, the ECMWF has been fairly consistent with its runs the last 3 cycles. With this in mind, the preference is for a non-UKMET blend with limited inclusion of the NAM for day 3. ...West of the Continental Divide... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Non-UKMET blend Confidence: Average 19Z Update: Model agreement has increased since the last cycle, though the 12Z UKMET is much faster with the shortwave trough moving into the Pacific Northwest Monday night. The rest of the guidance is clustered together well. For this, a non-UKMET blend is also preferred for the western CONUS. ---previous discussion--- A strong shortwave trough will approach the Pacific Northwest early next week. There is reasonable agreement in the latest model guidance in the strength of the system. However, there remains some timing differences, where the 00Z ECWMF is a bit faster than the 12Z GFS, and the 00Z CMC is the slowest. For now, the CMC appears to be the most outlier solution, and a blend of the other guidance is likely to yield a reasonable solution for now. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor