Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1228 AM EDT Tue Apr 14 2020 Valid Apr 14/0000 UTC thru Apr 17/1200 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 00Z Model Evaluation with Preferences and Confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Eastern half of CONUS --------------------- Model Blend Preference: 12Z ECMWF and 00Z GFS Confidence: Average Deep, intense surface cyclone over western Quebec and its associated cold front over the eastern U.S. will continue to march steadily eastward through the next 12-24 hours. The southern end of the frontal boundary is expected to stall/wash out over portions of the Southeast U.S. and Florida. A secondary area of low pressure is then forecast to develop along the boundary and move northeast offshore the Mid-Atlantic coast Wednesday into Wednesday night. There remains some sizable differences in the latest model guidance with respect to the north-south extent of the developing low and how quickly it lifts northeast. The 12Z UKMET was the slower of the models while the 00Z GFS and 12Z ECMWF showed some favorable agreement. A look at the ensembles would support a solution toward the ECENS/ECMWF and away from the slower UKMET. The 00Z GFS did trend toward the ECMWF, so through 16.00Z, the GFS can be incorporated across the eastern U.S. Western/Central CONUS -------------------- Model Blend Preference: Non-NCEP day 2/3 Confidence: Slightly above average Highly amplified ridge over the Eastern Pacific through the Gulf of Alaska will result in a blocky pattern and lower predictability forecast for a developing compact shortwave that rounds its periphery Tuesday before descending southward just offshore the Western CONUS. Similarly, another mid-level feature will descend through the flow from the Canadian Rockies through the Intermountain West and central Rockies. For the offshore system, the CMC remains an outlier with its fast progression and fractional pieces. The GFS looks reasonable offshore but for the interior shortwave, it ejects the mid-level low too strongly and thus has too strong of inflow and QPF. The non-NCEP guidance shows weaker flow and this is supported by the teleconnections with the anomaly over the eastern Pacific. Overall, a blend toward the ECENS with components of the 12Z ECMWF appear most reasonable at this time. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml Taylor