Extended Forecast Discussion NWS Weather Prediction Center College Park MD 751 PM EDT Wed May 29 2019 Valid 12Z Sat Jun 01 2019 - 12Z Wed Jun 05 2019 ...Overview/Weather Highlights and Guidance Evaluation/Preferences... Active flow with a North Pacific upper-level jet splits as it approaches the West Coast of North America. An upper-level low will persist this period near California in the southern stream, with a hot downstream upper ridge repositioning over the south-central U.S. as heights falls support more refreshing flow over the Southeast/East. Meanwhile, a western Canadian upper ridge shifts to central Canada and north-central U.S. by early next week. Farther east, northern stream energy will periodically encounter a persistent upper low over eastern Canada. These shortwaves will amplify as they dig into the Great Lakes and Northeast, traversing the broad cyclonic flow. Underneath, slower progressing southern stream energies will periodically eject from the California upper low, reaching the central U.S. and potentially interacting with amplifying northern stream energy. This combined with return flow into a slow moving barocliinc zone may prove significant next week in support of periods with strong to severe mcs/convection and locally heavy rainfall with a flood/flash flooding threat. A main threat area may focus from the south-central Plains to the mid-MS Valley. The WPC medium range product suite was mainly derived from seemingly reasonable and compatable 06 UTC GEFS and 00 UTC ECMWF ensemble guidance composite. Limited input from deterministic models was used given smaller scale convection/surface reflection detail variance. This maintains good WPC continuity as consistent with uncertainty. Schichtel Hazards: - Heavy rain across portions of the Central and Southern Plains, the Middle and Lower Mississippi Valley, the Great Lakes and the Ohio Valley, Mon-Wed, Jun 3-Jun 5. - Flooding possible across portions of the Northern, Central and Southern Plains, the Northern Rockies, the entire Mississippi Valley and the Great Lakes. - Flooding occurring or imminent across portions of the Northern, Central and Southern Plains, the entire Mississippi Valley, the Great Lakes and the Ohio Valley. - Flooding likely across portions of the Northern and Central Plains, the Upper and Middle Mississippi Valley and the Northern Great Basin. 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