Extended Forecast Discussion NWS Weather Prediction Center College Park MD 318 PM EDT Mon Mar 30 2020 Valid 12Z Thu Apr 02 2020 - 12Z Mon Apr 06 2020 ...Guidance/Predictability Assessment... The WPC medium range product suite was primarily derived from a blend of compatable guidance from the 06 UTC GFS and 00 UTC ECMWF/ECMWF ensemble mean days 3-5/Thu-Sat. This solution offers good WPC continuity and average predictability. Later, the models seem to have been having a more difficult time than usual recently at longer time frames due to pattern sensitivty upstream and/or data injest issues TBD. I asked for EMC/MEG to look into it as the GEFS and especially the GFS are again showing some big run-run continuity changes by day 6/7. The ECMWF/CMC are not immune to this issue either, especially inland from the Pacific. Accordingly, WPC Day 6/7 products gravitated to the ECMWF ensemble mean in a pattern with below normal predictability. ...Weather/Hazard Highlights... Precipitation will focus along/ahead of a shortwave lifting over the north-central U.S. Thu-Fri along the track of frontal low pressure from Kansas to Minnesota. Marginally cold air digging on the northwest side of the low offers a heavy snow risk, especially from the central Rockies through the Dakotas. Precipitation will become lighter farther east over the Great Lakes/Northeast this weekend as upper ridging only slowly relents. Underneath, a series of hard to time southern stream impulses will eject over TX and the lower MS Valley/central Gulf Coast states and combine with frontal/moisture convergence to produce a periodic local threat for heavy rains Thu-Mon. Meanwhile, the Pac NW will see some light rain/snow as a couple systems move through, but there is some signal for organized activity through CA and to a lesser extent the Intermountain West this weekend into early next week. The Sierra may have the most threat for heavy snow with this series of systems. 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 Southern Plains, the Upper Mississippi Valley, and the Northern Plains, Thu-Fri, Apr 2-Apr 3. - Heavy rain across portions of the Southeast, the Lower Mississippi Valley, and the Southern Plains, Sat-Sun, Apr 4-Apr 5. - Heavy rain across portions of the Southeast, the Lower Mississippi Valley, the Southern Plains, and the Tennessee Valley, Mon, Apr 6. - Heavy snow across portions of the Central Great Basin, California, and the Southwest, Sat-Mon, Apr 4-Apr 6. - Heavy snow across portions of the Central Rockies, the Central Plains, the Upper Mississippi Valley, and the Northern Plains, Thu, Apr 2. - 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 Great Lakes, the Middle Mississippi Valley, the Upper Mississippi Valley, the Southern Plains, and the Ohio Valley. - Flooding likely across portions of the Great Lakes, the Middle Mississippi Valley, the Southern Plains, the Upper Mississippi Valley, and the Northern Plains. - Much below normal temperatures across portions of the Central Plains, the Northern Plains, and the Northern Rockies, Thu-Fri, Apr 2-Apr 3. - Heavy precipitation across portions of mainland Alaska, Thu, Apr 2. - Much above normal temperatures across portions of mainland Alaska, Thu-Fri, Apr 2-Apr 3. 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