Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 139 PM EDT Sat Jun 06 2020 Valid Jun 06/1200 UTC thru Jun 10/0000 UTC ...See NOUS42 KWNO (ADMSDM) for the status of the upper air ingest... 12Z Model Evaluation Including Preliminary Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Amplifying trough moving across the Northeast late Saturday and Sunday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General Model Blend Confidence: Above average Overall, models are in good agreement through late Sunday -- indicating an amplifying trough moving across the Northeast Saturday into Sunday, before moving into Atlantic Canada and east of New England by late Sunday. ...Shortwave lifting from Utah into the northern High Plains Saturday night... ...Upper low developing over western Canada on Sunday.... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: 12Z UKMET/00Z ECMWF and EC Ensemble Mean Confidence: Average The GFS is showing a more amplified shortwave lifting across eastern Montana and western North Dakota Saturday night, with a deeper low closing off east of the Canadian Rockies on Sunday. The GFS also shows more phasing with this system and energy lifting out of a trough that is moving through the western U.S., with a redeveloping low over Saskatchewan late Monday. While the NAM indicates more phasing than the UKMET and 00Z ECMWF, it is farther west than the GFS. ...Closed low moving into the Pacific Northwest on Sunday... ...Upper trough moving from the Great Basin to the Plains Monday and Tuesday... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: General Model Blend through 12Z Tuesday, followed by a non-NAM blend Confidence: Average Overall, models are in good agreement -- showing an upper low dropping southeast into the Pacific Northwest on Sunday. This system is expected to transition to an open wave trough that will move through the Great Basin into the Rockies late Sunday and Monday. As described above, the GFS is less preferred with energy lifting out of the trough and the evolution of a low over central Canada; however, it is better clustered with the UKMET and 00Z ECMWF with energy moving through the base of the trough from the Four Corners region to the central Plains Monday night and Tuesday. Overall, the models are fairly well-clustered through early Tuesday, before the NAM becomes more of a less-amplified outlier across the Plains. ...Cristobal... ~~~~~~~~~~~~~~~~~~ Preference: 15Z NHC advisory Confidence: Refer to NHC products The 12Z NAM and GFS are both well-clustered with the 15Z NHC track guidance through Monday morning -- showing the system moving through northern Gulf of Mexico and making landfall over southeastern Louisiana Sunday evening. The NAM remains fairly well-clustered with the NHC track through early Tuesday across Arkansas and Missouri before racing out ahead of the NHC track and the other models as the system moves toward the Great Lakes. By early Tuesday, the GFS is slower than the NHC track and then moves west of the track by late Tuesday. The 12Z UKMET is east of the model consensus and NHC track as the system moves onshore and then on Tuesday it makes a slower turn across the mid Mississippi valley toward the Great Lakes. The 00Z ECMWF is west of the NCEP models and NHC track across Louisiana and Arkansas and then slower as the system turns toward the northeast on Tuesday. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Pereira