Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1246 AM EDT Sat Mar 16 2019 Valid Mar 16/0000 UTC thru Mar 19/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation Including Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 12Z ECMWF, 12Z ECMWF Ensemble, 12Z CMC Confidence: Slightly Above Average The synoptic pattern over North America should be persistent over the next few days -- this weekend into early next week -- with a highly amplified ridge along the West Coast providing some blocking. This amplifying ridge was downstream of a North Pacific Jet extension, and is typical of that jet evolution. Meanwhile, broad surface high pressure will settle over much of the CONUS. This should yield limited to zero precipitation over most of the US, with 0.25+ inch amounts generally restricted to south Texas and Florida. Therefore, minor model differences should not have a substantial impact on the precipitation forecast. Most model variation exists with some of the northern stream shortwaves cycling through the relatively stagnant pattern. One such shortwave will dig into the Canadian Prairies today and the Ohio Valley on Sunday. Models forecast a swath of light QPF in the region. The 00Z GFS continued a trend of being further north and wetter than other global models. With the region well removed from any significant tropospheric moisture, the preference was to lean toward models with lighter QPF -- in this case the 12Z ECMWF, UKMET and CMC, and the 12Z ECMWF ensemble mean. Another shortwave will approach the coast of British Columbia today, and eventually round the Northern Rockies. This eventually should support some precipitation in the central Plains by Monday Night. The 00Z NAM and 12Z UKMET lag the trough near Wyoming in almost a rex block, while the other models show much greater progression. The preference is to lean toward the consensus of the ECMWF, GFS and CMC. Given these individual preferences, the overall preference will be a stronger lean toward the 12Z ECMWF and 12Z ECMWF ensemble mean, with some 12Z CMC also included. Overall, though, model differences will not lead to significant QPF differences. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Lamers