Extended Forecast Discussion NWS Weather Prediction Center College Park MD 343 AM EDT Thu Oct 23 2025 Valid 12Z Sun Oct 26 2025 - 12Z Thu Oct 30 2025 ***Heavy rain for the Gulf Coast Sunday and snow increases for the Rockies through early next week*** ...General Overview... A split upper level flow pattern will be in place across the Continental U.S. for this weekend, with a southern stream shortwave crossing the south-central U.S., with heavy rain and some strong thunderstorms from Mississippi to Georgia. Meanwhile, an amplifying upper trough over the Western U.S. this weekend will herald a pattern change to the region, with colder conditions and widespread snow for the higher terrain through Monday, and periods of light to moderate rain for the Pacific Northwest coast. This western U.S. trough will likely spur surface cyclogenesis over the northern Plains that will result in another round of showers and storms early next week across the Upper Midwest. A separate low pressure system is likely to develop near the East Coast towards the middle of the week along a frontal boundary. ...Guidance/Predictability Assessment... The 00Z model guidance suite is in good overall agreement across the Continental U.S. for the weekend, with mainly minor mesoscale differences, so a multi-deterministic model blend was used through this time period. The 00Z CMC starts becoming noticeably more amplified with a second upper trough across the northern Rockies by Monday morning, and then extremely amplified with that trough going into Tuesday to the point of becoming an outlier solution from that time forward, as it develops an intense upper low over the central Plains that is not supported by ensemble or AIFS guidance, so no 00Z CMC is recommended beyond Monday. It is also on the northwestern side of the model track with the future track of what is currently Tropical Storm Melissa. However, the previous 12Z run was much better aligned with the other guidance in comparison across the Continental U.S. outside of the Tropics. It is also worth noting that the NBM is likely too light with rainfall across the Southeast U.S. for early next week, so the WPC QPF was higher given a heavier trend in the deterministic guidance. By the end of the forecast period, the GFS and ECMWF have trended stronger with a potential coastal low developing off the East Coast, with the GFS farther north and slower to develop it. The ensemble means were increased to about half by next Thursday amid the increased uncertainty in model specifics. ...Weather/Hazards Highlights... It remains the case that heavy rainfall can be expected across portions of the central Gulf Coast region going into Sunday as the southern stream shortwave tracks east across the region. There is a good model signal for 1 to 3 inch QPF from southern Mississippi to the Florida Panhandle, and therefore the inherited Marginal Risk area has been maintained for the Day 4/Sunday time period with a modest expansion to the east to include western Georgia. For the Day 5/Monday time period, the signal for heavier rainfall has increased for the coastal Carolinas as a potential low develops just offshore, and a Marginal Risk area has been introduced from near Charleston, SC to the southern Outer Banks of NC. There is a good chance that rainfall amounts could trend upward in later forecasts, so this region will continue to be monitored. Another thing that will make weather headlines is the increase of heavy mountain snow from the Cascades to the northern Rockies, where 1 to locally 2 feet of snow is becoming more likely for the higher ranges Sunday and into Monday afternoon. The intensity of the snow should taper off towards Monday night and beyond as forcing for ascent weakens. A new surface low is likely to develop by Monday across the northern Plains as a potent shortwave ejects eastward from the Rockies, supporting an increase in showers/storms and gusty winds from the Dakotas to Minnesota. The pattern change coming out West will result in colder weather from northern California and Oregon eastward to the Great Basin and northern Rockies through Monday. Highs are expected to be 5 to 15 degrees below average, perhaps locally more, but overnight lows should be closer to average owing to increased cloud cover and precipitation. Late season warmth should be the case from the Dakotas to the Midwest through Monday before these areas also get a cool down towards next Wednesday as colder high pressure builds in behind the cold front. Much of the East Coast region should generally be slightly below average through most of the forecast period. Hamrick 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