Extended Forecast Discussion NWS Weather Prediction Center College Park MD 436 PM EST Wed Mar 09 2022 Valid 12Z Sat Mar 12 2022 - 12Z Wed Mar 16 2022 ...Winter storm lifts away from the Northeast Saturday night... ...Overview... A rapidly developing and powerful low will lift northeast from Maine Saturday evening with trailing modified Arctic air shifting east/southeast off the East Coast/Gulf Coast Sunday with subfreezing temps reaching the Gulf and Southeast coasts Sunday morning. An active pattern returns to the Pacific Northwest with a trough late Saturday and another Monday night/Tuesday. This weekend wave out west shifts southeast to the Gulf Coast through Monday night before shifting east across the Southeast through the midweek. Meanwhile, the second western wave may become more positively tilted/linger over the Intermountain west through the midweek. ...Guidance Evaluation/Predictability Assessment... Good deterministic model agreement is noted with the departing strong low Saturday night. However, for the Pacific Northwest trough pushing inland Saturday night the 00Z CMC is much less amplified than consensus, so deterministic weighting favored the 00Z ECMWF/UKMET and the 06Z GFS for Days 3-5 as the trough digs southeast to the southern Rockies. The next opening low/trough into the Pacific Northwest Tuesday has some amplitude uncertainty (EC more amplified) and the system tracking through the Southeast is shown in both the 00Z ECMWF and 06Z GFS, but the ECMWF is more progressive (with the 12Z GFS even slower), so the Days 6/7 WPC forecast incorporates 00Z ECENS and 06Z GEFS ensemble means to help mitigate these differences while keeping some semblance of a system across the Southeast early next week. ...Weather Highlights/Threats... As the low pressure continues to rapidly deepen as it pushes away from Maine Saturday night, strong gusty winds will persist over the Northeast Saturday night and northern New England into Sunday. Wrap around snow bands persist into Saturday night over northern New England/NY. The trailing Arctic cold front will be progressive and quickly bring an end to the heavy rain over the lower Southeast Saturday night. However, behind the front, temperatures of 20 to 25 degrees below normal will spread across the entire Gulf Coast, Southeast, and Ohio Valley with subfreezing temperatures expected Sunday morning down to the eastern Gulf Coast and northern Florida with record lows likely in several locations. Meanwhile, rain and mountain snows return to the Northwest late Saturday and continue into Tuesday with the second trough passage. The trough early next week looks to direct an atmospheric river across the Pacific Northwest with heavy rain and higher terrain snow across western Washington/Oregon and northern California, with additional snowfall farther inland across the northern Rockies. Upper level ridging between these troughs will build across the central U.S. with daytime highs 10 to 25 degrees above normal by next Tuesday for the northern/central Plains, which should be a welcome relief to the very chilly and snowy weather currently over the central Plains. Rain chances increase again over the Gulf Coast and Southeast Monday night, possibly lingering into Wednesday depending on the progression of the low tracking through. Jackson Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php Hazards: - Heavy precipitation across portions of the Pacific Northwest and the Northern Great Basin, Sat-Tue, Mar 12-Mar 15. - Heavy precipitation across portions of the Mid-Atlantic, the Northeast, and the Central Appalachians, Sat, Mar 12. - Heavy rain across portions of California and the Pacific Northwest, Mon-Tue, Mar 14-Mar 15. - Heavy rain across portions of the Northeast, Sat, Mar 12. - Heavy snow across portions of the Northern Rockies and the Northern Great Basin, Sun-Mon, Mar 13-Mar 14. - Heavy snow across portions of the Northeast, the Central Appalachians, the Mid-Atlantic, the Lower Great Lakes, and the Ohio Valley, Sat, Mar 12. - Severe weather across portions of the Southeast and the Mid-Atlantic, Sat, Mar 12. - Flooding possible across portions of the Pacific Northwest. - Flooding occurring or imminent across portions of the Middle/Lower Mississippi Valley, and the Ohio Valley. - Flooding likely across portions of the Middle Mississippi Valley and the Lower Mississippi Valley. - High winds across portions of the Great Lakes, the Mid-Atlantic, the Northeast, and the Central Appalachians, Sat-Sun, Mar 12-Mar 13. - Much below normal temperatures across portions of the Plains, the Mississippi Valley, the Great Lakes, the Ohio Valley, and the Southwest, Sat, Mar 12. - Much below normal temperatures across portions of the Middle/Lower Mississippi Valley, the Central/Southern Appalachians, the Tennessee Valley, the Great Lakes, the Mid-Atlantic, the Southeast, the Southern Plains, and the Ohio Valley, Sun, Mar 13. 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