Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 250 AM EST Wed Feb 05 2020 Valid Feb 05/0000 UTC thru Feb 08/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Final Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ ...Evolving full latitude trough over the Central US through Thu... ...Surface wave developing over the Lower MS Valley...moving into the interior Mid Atlantic late ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~ Preference: non-GFS blend Confidence: Average to slightly below average GOES-East WV depicts the full latitude trough across the Center to Southwestern portion of the CONUS. The northern stream shortwave is already departing/severing connection to the main elongated upper level trof. Through 48 hours, the guidance is in reasonable agreement such that a general model blend can be used. Beyond that time frame, when the long wave trough begins to take on a neutral to negative tilt, the 00Z operational GFS races out ahead of the rest of the guidance. It is also noted that the surface low is well to the west (inland) compared to the rest of the guidance for Day 3. This has major implications for QPF and thermals and overall is not as favored at this time given the higher agreement between the ECMWF/UKMET/NAM/CMC. The 18Z GEFS mean would also be good to include as its relatively similar to the other solutions. ...Pulses along atmospheric river Wed-Fri into Pacific NW... ...Approaching rapidly deepening cyclone toward Pacific NW by end of Day 3... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ Preference: 12Z ECMWF/UKMET and 00Z GFS blend Confidence: Average Ridging is expected to persist across the western U.S. through the first couple of days and then toward Friday/Friday night/Saturday a rather compact and impressive shortwave trough races into the Pacific Northwest. Forecast confidence is about average right now with some notable spread seen in the latest guidance. The CMC is the fastest outlier solution, well ahead the rest of the deterministic guidance and the ensemble means. The UKMET/ECMWF offer a middle ground approach and show relatively similar strength (ECMWF is a bit stronger) while the 00Z GFS is weaker (not closed at 500 mb). The NAM is the slowest and strongest solution. Despite the differences aloft, the 00Z GFS surface reflection is fairly consistent with the more agreeable ECMWF/UKMET, so some inclusion of the GFS appears sufficient. With all this in mind, will lean toward a 12Z ECMWF/UKMET and 00Z GFS blend for this cycle. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor