Extended Forecast Discussion NWS Weather Prediction Center College Park MD 207 AM EDT Thu Apr 30 2020 Valid 12Z Sun May 03 2020 - 12Z Thu May 07 2020 ...Much above normal temperatures for the South into early next week then shift back to the West... ...Parade of active weather systems to affect the Nation... ...Guidance/Predictability Assessment... The WPC medium range product suite was primarily derived from a composite blend of the 12 UTC GFS/ECMWF and GEFS/ECMWF ensemble means days 3-7. Applied increasingly greater weightings to the ensembles over time consistent with increasing forecast spread and uncertainty. GFS/ECMWF solutions offer some small-mid scale system similarities into longer time frames that was included in the blend to a degree, but was hesitant given a lack of good ensemble amplitude/timing support nor great run-run continuity. ...Weather/Hazard Highlights... Above normal temperatures will spread from the Southwest/Rockies through the South this weekend and linger early next week. Temperatures will range up to 10-20F above normal, with daily records most likely over the southern Plains. Upstream upper ridge rebuilding over the West may support hot temperatures by next midweek to include some record southern CA/Southwest U.S. values. Upper trough and jet energies in two streams will amplify/dig from the north-central U.S. through the East Sun. Rainfall may focus through the Mid-MS/OH Valleys and central Appalachians/Mid-Atlantic. Dynamics, instability and progressive frontal pushes may support some organized strong to severe convection with locally heavier downpours. Upstream, robust eastern Pacific trough energy/height falls will work inland across the West Sun into Mon and spread a swath of moderate precipitation mainly from the Northwest through the northern Rockies. Favored higher elevations may see periods of enhanced snow. The dynamic system should emerge over the north-central U.S. Mon before digging into the East through next midweek. Forecast spread and guidance uncertainty quickly increases at these longer time frames, but the larger scale flow suggests that an associated frontal system and lead instability may favor a risk of strong to severe convection with some heavy downpours from the north-central Plains southeastward through the MS Valley then onward to the Appalachians/Mid-Atlantic/Northeast. 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