Extended Forecast Discussion NWS Weather Prediction Center College Park MD 207 PM EST Fri Feb 28 2025 Valid 12Z Mon Mar 03 2025 - 12Z Fri Mar 07 2025 ...Severe weather and heavy rain potential likely to focus in Lower/Middle Mississippi Valley and Mid-South on Tuesday and perhaps the East on Wednesday... ...Overview... An active upper pattern over the lower 48 will be progressive in split flow next week. In the wake of lead troughing exiting the East, a weakening southern stream trough/low absorbed within the larger scale flow will traverse from the south-central U.S.through the eastern states Monday. Meanwhile, an upstream and deep trough/closed low will advance into the West with focus over the Southwest by Monday and spread organized precipitation and some terrain focusing high winds across the region. As this system emerges, expect major cyclogenesis over the Central Plains by Tuesday with subsequent track northeast Wednesday-Thursday across the Midwest and into eastern Canada. High winds are possible on the backside of this low. Expect widespread wrapping rains around the low, with enhanced snow chances on the northern periphery up through the Upper Midwest/Great Lakes and northern portions of the Northeast. Locations ahead of the trailing cold front will be primed for severe thunderstorms and heavy rainfall that could led to areas of flooding across the south-central U.S. peaking over the east-central U.S. Tuesday, with some threat continuing into Wednesday in the East. Another amplified trough approaches the West Coast/Southwest and onward next Thursday/Friday. ...Guidance/Predictability Assessment... Forecast confidence has grown for the upcoming medium range period next week as guidance continues to generally converge upon a better clustered overall solution, albeit with lingering smaller scale system differences. This WPC medium range product suite was primarily produced from a broad composite of the full suite of models and ensembles along with WPC continuity and the National Blend of Models. ...Weather/Hazards Highlights... The trough coming into the western/Southwestern U.S. early next week will also lead to orgainzed precipitation spreading across the West Coast into the Great Basin and Rockies, with lower elevation rain and higher elevation snow as well as gusty winds. Precipitation totals are expected to be generally limited as the moisture influx into the region will be modest. As this feature exits into the south-central U.S., Gulf moisture and instability will be drawn northward to fuel more widespread and heavy rains from the southern to eastern U.S. The latest guidance continues to signal the heaviest rainfall accumulations to set up from the Lower/Middle Mississippi Valley to Southeast and Tennessee/Ohio Valleys on Tuesday. Some areas have wet antecedent soil conditions, which would exacerbate flood potential. Severe weather is also a notable threat over the south-central U.S. as per SPC. WPC has introduced a Marginal Risk and Slight Risk areas for excessive rainfall for portions of the Lower/Middle Mississippi Valley into western portions of the Tennessee Valley under a favorable coupled upper jet. Precipitation should overspread the East on Wednesday, and SPC continues to show severe potential in the Southeast to southern Mid-Atlantic. Areas of heavy rainfall become even more uncertain with placement at that time, but may become problematic in terms of flooding if heavy rain falls on snow covered areas of the Northeast, per the National Water Center. Northwest of the low track, it may be cold enough to support enhanced snow across parts of the north-central Plains/Upper Midwest into the Great Lakes, and especially into southern/southeast Canada. High/gusty winds are also possible on the backside of the deep surface low. Another round of moderate rain and elevation snow should move into California next Wednesday-Thursday with the next upper trough. Much above normal temperatures over the Rockies and Plains states on Sunday will gradually progress eastward with time and moderate. The greatest anomalies, 15 to 25 degrees above normal, will be across the northern Plains through Monday. Temperatures across much of the East will be considerably colder than normal on Sunday, but should moderate back to normal Monday-Tuesday, and warmer than normal Wednesday. By next Thursday, much of the country may be near or within a few degrees of normal. Campbell/Schichtel 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 WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw