Extended Forecast Discussion NWS Weather Prediction Center College Park MD 216 PM EDT Wed Apr 10 2019 Valid 12Z Sat Apr 13 2019 - 12Z Wed Apr 17 2019 ...Lead Heavy Rainfall Threat for the Mid-Lower Mississippi/Ohio Valleys and South... ...A Second Storm Threat through the West to the East-Central U.S. next week... ...Weather Highlights/Hazards and Guidance/Predictabillity Assessment... A major system exits the Southwest/Southern Rockies to the southern Plains and mid-lower MS/OH Valleys this weekend, bringing widespread enhanced rains/deepening Gulf moisture with potential of excessive rainfall, flash flooding, and strong to severe lead warm sector convection over the South. The potent low and wrapped precipitation will track over the Northeast Monday as its trailing cold front works precipitation/convection underneath arcoss the southeast and eastern states before exiting into the Gulf of Mexico and western Atlantic. A composite blend of the overall compatable 06 UTC GFS and 00 UTC ECMWF/UKMET seems to offer a reasonable depiction of the storm. Meanwhile upstream, models/ensembles overall agree to bring another potent mid-upper level trough/ample height falls/frontal precipitation into the West Coast Sunday with a subsequent emphasis digging down across the West to the snowy Rockies into Mon-Tue before emerging over the Plains into next midweek. The model and ensemble signal is growing in support of this scenario with GFS/ECMWF and GEFS leading the way with more pronounced southern stream flow separation that has been the case with recent systems. This suggests potential for downstream southern Plains storm genesis next Wed that portends a renewed lead return flow of deepening Gulf moisture and an enhancing precipitation/convection shield and flooding threat over an east-central U.S. already wettened by the lead storm. Schichtel Hazards: - Heavy precipitation across portions of the Pacific Northwest and the Northern Great Basin, Sun-Tue, Apr 14-Apr 16. - Heavy precipitation across portions of the Central Rockies, the Central Great Basin, the Northern Rockies, the Northern Great Basin, and the Northern Plains, Mon-Tue, Apr 15-Apr 16. - Heavy precipitation across portions of the Northern Rockies and the Northern Great Basin, Sun-Mon, Apr 14-Apr 15. - Heavy rain across portions of the Mid-Atlantic, the Lower Mississippi Valley, the Central Appalachians, the Tennessee Valley, the Great Lakes, the Middle Mississippi Valley, the Northeast, the Southern Appalachians, the Southeast, the Southern Plains, and the Ohio Valley, Sat-Sun, Apr 13-Apr 14. - Heavy rain across portions of the Lower Mississippi Valley, the Tennessee Valley, the Middle Mississippi Valley, the Southern Appalachians, the Southeast, the Southern Plains, and the Ohio Valley, Wed, Apr 17. - Heavy rain across portions of the Northeast, Mon-Tue, Apr 15-Apr 16. - Heavy snow across portions of the Northeast, Mon-Tue, Apr 15-Apr 16. - Severe weather across portions of the Southeast, the Lower Mississippi Valley, the Southern Plains, and the Tennessee Valley, Sat, Apr 13. - Severe weather across portions of the Southeast, the Mid-Atlantic, the Southern Appalachians, and the Tennessee Valley, Sun, Apr 14. - Flooding possible across portions of the Middle Mississippi Valley, the Great Lakes, the Upper Mississippi Valley, and the Northern Plains. - Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Northern Plains, the Tennessee Valley, the Northern Rockies, the Middle Mississippi Valley, the Northern Great Basin, the Upper Mississippi Valley, the Pacific Northwest, and the Ohio Valley. - Flooding likely across portions of the Central Plains, the Northern Plains, the Northern Great Basin, the Middle Mississippi Valley, the Upper Mississippi Valley, and the Southern Plains. - Much below normal temperatures across portions of the Central Plains, the Central Rockies, the Northern Plains, the Southern Rockies, the Upper Mississippi Valley, and the Southern Plains, Sat-Sun, Apr 13-Apr 14. 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