Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 308 AM EST Sat Mar 07 2020 Valid Mar 07/0000 UTC thru Mar 10/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model evaluation with preferences and confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overall Pattern Across the CONUS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General model blend through 09.12Z, then a 00Z ECMWF/ECENS, 00Z GEFS mean Confidence: Slightly above average 08Z update: No significant changes/differences noted with the rest of the 00Z guidance. Preferences remain the same from previous issuance. Current synoptic pattern across the CONUS features upper level troughing over the eastern U.S. and just offshore the west coast with ridging through the central US. As the ridging works eastward over the next 24-36 hours, troughing/southwesterly flow is expected to develop over the western/central US as a couple shortwaves work through the flow. One shortwave arrives across the Pacific NW late in the weekend and treks across the northern Plains early next week. In the southern stream, a weak shortwave trough moves from southern CA toward the central Rockies/central Plains early next week, reaching the Great Lakes Tuesday. Finally, a more anomalous upper level shortwave begins to approach the southern CA coast by the end of the forecast period / Tuesday-Wednesday/. In a broad sense, the latest deterministic guidance agrees well with continuity and run to run trends as well as well within the ensemble spread. Through 48 hours (09.00Z) a general model blend can be used. Beyond that time, the 00Z GFS trends faster than the rest of the guidance, particularly with the northern stream shortwave on day 3 as well as the impulse that ejects into the central Plains. For the closed low off southern CA, the 00Z GFS did trend slower from its earlier run but still is faster than the rest of the guidance. The preference then is for a blend toward the 12Z ECMWF/ECENS mean and 00Z GEFS mean. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor