056 FXUS02 KWBC 301959 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sun Aug 30 2026 Valid 12Z Wed Sep 02 2026 - 12Z Sun Sep 06 2026 ...Dangerous heat continues from the central and southern Plains eastward to the Midwest, Mid-Atlantic, and Southeast through late week... ...Pattern Overview... A late summer heat wave will continue to bring scorching hot temperatures to much of the south-central and southeastern U.S. through mid to late week before a cold front brings some relief next weekend. Meanwhile, a strong Pacific storm coupled with a potential atmospheric river will bring notable rainfall to parts of the Pacific Northwest Wednesday into Thursday. Downstream, heavy rainfall and severe weather will be possible from the northern Plains and the Upper Midwest to the Great Lakes, Mid-Atlantic, and Northeast. ...Guidance/Predictability Assessment... Models are in good agreement regarding the general synoptic pattern evolution across the lower 48 during the medium range period (Wednesday--Sunday). Upper troughing settling over the West Coast, a digging trough over the East Coast and ridging over the Central U.S. are well represented in most of the guidance. The main areas of uncertainty are around the timing of shortwave energy ejecting out from the West Coast low and into south-central Canada as well as the timing of mid-level disturbances propagating through the Gulf Coast and Florida Peninsula. ...Weather/Hazards Highlights... Intense late-summer heat with high temperatures well into the 90s and 100s will persist from the central and southern Plains to the Midwest, Mid-Atlantic, and Southeast through mid to late week as a large and sprawling mid/upper ridge dominates the region. Some relief is possible by next weekend as a cold front presses in from the north (especially parts of the Ohio Valley and Mid-Atlantic), but the core of the heat will likely continue from the central/southern Plains to the Mid/Lower Mississippi Valley into the second week of September. Well above normal temperatures combined with high humidity and very warm overnight lows in the 70s to near 80 will result in widespread areas of Major to Extreme HeatRisk and a concern for heat-related illnesses. Please see WPC's Key Messages for more details. A Pacific storm descending out of the Gulf of Alaska coupled with a weak to moderate atmospheric river will bring heavy rainfall to parts of the Pacific Northwest Wednesday through Thursday with lighter showers likely lingering into Friday. The heaviest rain will mostly fall on Wednesday and be confined to coastal areas of Washington and Oregon, along with the Cascades. The rainy, cloudy, and generally unsettled weather associated with the storm itself and persistent troughing along the West Coast will help to keep temperatures on the cooler side of normal through the end of the week and into next weekend. Farther downstream, a frontal system and a series of mid-level impulses tracking eastward along the northern periphery of the elongated mid/upper ridge will interact with anomalous moisture and instability to produce episodes of heavy rainfall and possible severe weather from the northern Plains, Upper Midwest, Great Lakes, and Northeast mid to late week. On Wednesday in particular, there is a growing signal for severe thunderstorms and notable rainfall across portions of the Interior Northeast and New England. The rain could be heavy enough to produce isolated to scattered instances of flash flooding, especially in urban, low-lying, and poor drainage areas. Elsewhere, after a brief reprieve, another surge of monsoonal moisture is likely to bring a return to more numerous showers and thunderstorms across parts of the Southwest and Intermountain West by Thursday or Friday and possibly lasting through next weekend. Meanwhile, underneath the strong ridge to the north, small scale disturbances interacting with plenty of moisture will result in daily chances for scattered to numerous thunderstorms across the Deep South, Gulf Coast, and Florida through next weekend. Many of these storms will contain heavy rainfall rates, leading to the potential for localized to scattered flash flooding. Kebede/Miller 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, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#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 $$