Extended Forecast Discussion NWS Weather Prediction Center College Park MD 245 AM EDT Sun Apr 26 2020 Valid 12Z Wed Apr 29 2020 - 12Z Sun May 03 2020 ...Much above normal temperatures spread from the West to the Plains mid-late week... ...Stormy weather to progress across the eastern U.S. mid-late week... ...Guidance/Predictability Assessment... Models and ensembles continue to depict an amplified upper-level pattern that will progress slowly eastward across the lower 48 midweek into next weekend. A pronounced upper ridge from the western to central U.S. will be contrasted with an upper trough/closed low over the East where a moderately strong low pressure system is forecast. Model solutions have converged on a more common overall solution consistent with a recent trend toward a slower eastward progression of this low and deeper and more closed off upper vortex. There is a growing guidance signal for amplified eastern Pacific troughing to work more robustly across the West Coast into later next weekend. Accordingly, The WPC medium range product suite was primarily derived from a blend of reasonably well clustered guidance of the 18 UTC GFS/GEFS, 12 UTC ECMWF/ECMWF ensembles and the 01 UTC National Blend of Models days 3-7 in a pattern with above average predictability. This composite solution maintains great WPC continuity and acts to mitigate the less certain smaller scale weather features and interactions. ...Weather/Hazard Highlights... An amplified western U.S. upper ridge midweek will shift over the central U.S. later week. This amplified ridge will support much above normal temperatures to include a risk of record maximum/minimum temperature values from the Southwest to south-central portions of the Great Basin/Rockies/Plains. Temperatures will moderate in the wake of the exiting upper ridge as Pacific system moisture/height falls work over the West. This should promote mainly modest precipitation over the West, but could then support some organized weekend convection downstream over the north-central states. More robust system energies/height falls upstream work inland from the Pacific later next weekend along with the chance for enhanced precipitation for the Northwest. Lead trough energies will meanwhile significantly dig over e-central U.S. downstream of the ridge. This will carve out an amplified mid-upper level trough/closed low and generate a well organized surface low from the Great Lakes/OH Valley to the Northeast Wed into Fri. The main low and frontal system will sweep across the east-central to eastern U.S. and tap Gulf of Mexico and Atlantic moisture to fuel an swath of moderately heavy rainfall/strong to possibly severe thunderstorms. Coastal low redevelopment may enhance Northeast rainfall and offshore maritime hazards into Fri. Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml