Extended Forecast Discussion NWS Weather Prediction Center College Park MD 449 PM EDT Tue Mar 24 2020 Valid 12Z Fri Mar 27 2020 - 12Z Tue Mar 31 2020 ...Southwest U.S. to North-Central U.S. to Northeast Storm Threat Friday-Monday... ...Guidance/Predictability Assessment... A deepening area of low pressure from the central Plains toward the Upper Midwest and Great Lakes later this week and into the weekend highlights the medium range period. The product suite was primarily derived from a blend of the 00Z ECMWF, 06Z GFS, and 00Z UKMET initially. By day 6-7, the increasing model spread and higher forecast uncertainty leads to overall lower confidence such that more emphasis was placed on the 00Z ECENS ensemble mean, though some inclusion of the 06Z GEFS mean was incorporated. ...Weather/Hazard Highlights... Anomalous positively tilted trough axis ejects out into the central Plains during the day 3-4 time frame resulting in a deepening area of low pressure that is expected to track from the Central Plains Friday to the Midwest/Great Lakes and Northeast Saturday through early next week. In the warm sector, stronger convection is possible while interactions along a stationary/wavy frontal boundary will focus heavier rainfall from the Ohio Valley through portions of the central Appalachians and Mid-Atlantic. The signal remains for a northern tier banded precipitation which could bring a threat for heavier snow/wind from portions of the north-central Plains to the Upper Midwest and Great Lakes regions. Out West, the Northwest will see periods of rain and mountain snow of varying intensity as progressive flow from the northeast Pacific carries along multiple features. Especially by the latter half of the period there is rapidly decreasing confidence in the southern extent of precipitation. Highest totals for the five-day period should be along favored Olympics/Washington Cascades terrain. The West will experience below normal temperatures late this week with moderation over the weekend. Expect decent coverage of minus 10-20F anomalies for highs over central/southern parts of the West into Fri. On the other hand a broad area of above to much above normal temperatures will spread from the Southern Plains and vicinity across much of the East late this week into the weekend. Highest anomalies will likely be for morning lows, up to 15-25F above normal versus 10-20F anomalies being more common for daytime highs. Multiple locations may see daily records for highs and/or warm lows from the Southern Plains eastward. Frontal passage will bring temperatures down to near normal over the eastern half of the country by Sun-Mon. Schichtel/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 precipitation across portions of the Pacific Northwest and the Northern Great Basin, Fri-Mon, Mar 27-Mar 30. - Heavy rain across portions of the Lower Mississippi Valley, the Tennessee Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, and the Southern Plains, Mon-Tue, Mar 30-Mar 31. - Heavy rain across portions of the Northeast, the Central Appalachians, the Middle Mississippi Valley, the Mid-Atlantic, the Great Lakes, and the Ohio Valley, Fri-Sat, Mar 27-Mar 28. - Severe weather across portions of the Central Plains, the Middle/Lower Mississippi Valley, and the Southern Plains, Fri, Mar 27. - Severe weather across portions of the Lower Mississippi Valley, the Ohio Valley, and the Tennessee Valley, Sat, Mar 28. - Flooding possible across portions of the Middle Mississippi Valley, the Southern Appalachians, the Ohio Valley, and the Tennessee Valley. - Flooding occurring or imminent across portions of the Middle/Lower Mississippi Valley, the Northern Plains, the Southeast, the Southern Plains, and the Ohio Valley. - Flooding likely across portions of the Mississippi Valley and the Northern Plains. - Much above normal temperatures across portions of the Lower Mississippi Valley, the Tennessee Valley, the Mid-Atlantic, the Southern Appalachians, the Southeast, and the Southern Plains, Fri-Sun, Mar 27-Mar 29. - Much above normal temperatures across portions of the Great Lakes, the Upper Mississippi Valley, and the Northern Plains, Mon-Tue, Mar 30-Mar 31. - Enhanced wildfire risk across portions of the the Southern Rockies, the Central Rockies, the Southern Plains, the Central Plains, and the Southwest, Fri, Mar 27. 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