Extended Forecast Discussion NWS Weather Prediction Center College Park MD 514 PM EDT Thu Oct 10 2019 Valid 12Z Sun Oct 13 2019 - 12Z Thu Oct 17 2019 ...Pattern Overview and Guidance/Uncertainty Assessment... The deep closed upper low over the Upper Midwest Sunday will slowly lift toward James Bay early next week, keeping cyclonic flow over the eastern CONUS. Another shortwave trough and its associated cold front drops through the Pacific Northwest and eventually through the Plains Tuesday and then into the Northeast U.S. mid to late week. Another pair of fronts will then approach the Pacific Northwest by the end of the forecast period. For this cycle, the 00Z ECMWF and ECENS mean were the primary component of the model blend preference. For Day 3-4, model spread was low enough to include the deterministic runs of the ECMWF/GFS/CMC/UKMET, with inclusion of both the 00Z and 06Z GFS. By Day 5-7, uncertainty increases, particularly across the northeast Pacific, as the extratropical transition of Hagibis impacts the overall synoptic pattern. An ensemble blend weighted toward the 00Z ECENS mean was used for Day 6-7. ...Weather Highlights/Threats... A stalled front across the Southeast and Gulf Coast region will be the focus for showers and thunderstorms Sunday through Tuesday with slightly above normal precipitable water values in place. Moisture may be lifted into the region from eastern Pacific sources, but questions remain on how much influence there may be with a weakening area of disturbed weather. Another approaching front and low pressure sweeping the central/eastern US on Wed-Thur will be the focus for rainfall from the lower Mississippi Valley toward the mid-Atlantic and Northeast. Below normal temperatures will persist late this weekend into early next week across the northern Plains. Moderation is expected toward the middle of next week. The South will see above average temperatures through mid-week followed by near normal to slightly below normal as Canadian high pressure sweeps through the eastern CONUS. Fracasso/Taylor 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 Northeast, the Pacific Northwest, the Northern Mid-Atlantic, California, and the Lower Great Lakes, Wed-Thu, Oct 16-Oct 17. - Heavy rain across portions of the Southeast, the Southern Mid-Atlantic, the Lower Mississippi Valley, the Southern Appalachians, and the Tennessee Valley, Mon-Wed, Oct 14-Oct 16. - Flooding possible across portions of the Plains, the Upper/Middle Mississippi Valley, and the Great Lakes. - Flooding occurring or imminent across portions of the Northern/Central Plains, the Upper/Middle Mississippi Valley, and the Great Lakes. - Flooding likely across portions of the Middle Mississippi Valley and the Northern Plains. - Much below normal temperatures across portions of the Northern/Central Plains, the Upper/Middle Mississippi Valley, and the Great Lakes, Sun-Wed, Oct 13-Oct 16. 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