Extended Forecast Discussion NWS Weather Prediction Center College Park MD 247 PM EDT Tue Oct 01 2019 Valid 12Z Fri Oct 04 2019 - 12Z Tue Oct 08 2019 ...Guidance/Uncertainty Assessment... The WPC medium range product suite was primarily derived from a composite blend of well clustered solutions from the 06 UTC GFS/GEFS and 00 UTC ECMWF/ECMWF ensembles. This solution maintains good WPC continuity for much of the forecast period in a pattern with seemingly above normal forevcast predictability. ...Weather Pattern Highlights/Threats... An amplified upper trough works over the West Friday as a northern stream upper trough clears the Northeast well downstream. A surface low pressure system moving pass New England then will bring focused rainfall to areas near/north of the low track. Rainfall along the trailing front will diminish except for some activity persisting over the southern Rockies/High Plains where the front stalls. The western U.S. upper trough and developing surface system progresses across the Rockies and into the Plains to bring scattered rain/high elevation snow to northern parts of the West late week and areas of locally moderate to heavy rain over the central U.S. this weekend. Enhanced rains will reform eastward with frontal progression/moisture pooling and dynamic support aloft through the Appalachians/Northeast and vicinity later weekend into early next week. The forecast becomes more uncertain early next week given pre-frontal flow differences that will determine frontal timing/waviness and how much moisture may flow northward from the Gulf of Mexico. WPC progs now show a more progressive front than continuity, but there remains potential for some significant Southeast rains even with discount of the wetter Canadian model guidance after collaboration with NHC. Record warmth over the eastern and southeastern U.S. should largely come to an end on Friday behind a cold front. Meanwhile, expect unseasonably cool readings over the Northwest (10-20F below normal) to persist late this week and then trend closer to normal over the Pacific Northwest followed by the northern Rockies. 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 Hazards: - Heavy rain across portions of the Central Plains, the Middle Mississippi Valley, and the Upper Mississippi Valley, Sat, Oct 5. - Flooding possible across portions of the Central Plains, the Northern Plains, the Middle Mississippi Valley, the Upper Mississippi Valley, the Great Lakes, and the Ohio Valley. - Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi Valley, the Great Lakes, and the Northern Plains. - Flooding likely across portions of the Central Plains, the Middle Mississippi Valley, and the Upper Mississippi Valley. - Much above normal temperatures across portions of the Southeast, Fri, Oct 4. 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