443 FXUS02 KWBC 250806 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 406 AM EDT Fri Sep 25 2026 Valid 12Z Mon Sep 28 2026 - 12Z Fri Oct 02 2026 ...Early season New England Nor'easter lingers early next week... ...Multi-day Four Corners states to Plains/Mississippi Valley heavy rain/runoff/tropical moisture connection threat next week... ...Overview... An early season Nor'easter will linger off New England early next week before exiting into the Canadian Maritimes. Strong/gusty winds with potential for coastal flooding, beach erosion, and rip currents are possible, along with heavy coastal rains. Meanwhile, an upper trough will work through the West/Southwest early next week and move east as next week progresses. Heavy precipitation will be widespread ahead of this trough and with lead/wavy multi- stream frontal system interactions. A tropical moisture connection as East Pacific Hurricane Polo landfall in Mexico favors multiple days of rain/storms and some mountain snows in the Four Corners states, with widespread heavy rainfall/runoff issues spreading across the Plains and Mississippi Valley as next week progresses. ...Guidance/Predictability Assessment... Models and ensemble forecast continuity and clustering for flow embedded systems has proven less than stellar over the past few cycles despite reasonably similar larger scale pattern evolutions. Forecast confidence remains high with development and lingering of an early season Nor-easter and associated threats even though details remain less certain. Model and ensemble guidance has highlighted the interaction of deep lead moisture from Mexico landfalling East Pacific Hurricane Polo and the Gulf into/ahead of an emerging West/Southwest upper trough and wavy multi-stream frontal systems downstream over the central U.S.. While details and axis/orientation are varied, there is above normal confidence in threat development, leaning models and ensembles toward machine learning guidance to better match with the latest NHC track. ...Weather/Hazards Highlights... The western Atlantic Nor'easter will lead to broad onshore flow from the Mid-Atlantic to the Northeast, continuing early next week. The lingering storm could lead to coastal flooding and beach erosion, as well as marine hazards like rip currents and high surf. Heavy rain could cause inland flooding across southeastern New England. See WPC's Key Messages regarding this coastal low for further information. Deep tropical Pacific and Gulf moisture should return ahead of the large-scale troughing into an unsettled/cooled West, bringing widespread rain to the Four Corners states northward and eastward into early next week. Moderate to heavy rain spreads across the Plains and Mississippi Valley into early-mid next week. A slow moving upper low will interact with tropical moisture from Polo, leading to heavy to excessive rainfall threats across the Four Corners Monday to Tuesday/Wednesday. A WPC Excessive Rainfall Outlook (ERO) Slight Risk area is in place for Monday. Vulnerable soils from recent heavy rainfall could exacerbate flash flooding concerns. Some snow is possible in the higher peaks of the Intermountain West/Rockies with the precipitation, as the trough pushes east into the Plains on Wednesday/Thursday and cools temperatures. A Slight Risk ERO has also been introduced for the south-central U.S. for Tuesday, with later week risks to monitor. Meanwhile, expect what has been a protracted wet period for Florida is expected to linger into early October as onshore moisture flow fuels enhanced daily rain chances. Warmer than average temperatures will persist in the south-central U.S. into early next week under an upper ridging, and highs in the 90s are forecast through the southern Plains and Lower Mississippi Valley. On the other hand, cooler than average temperatures (especially for highs) are forecast for the West under troughing aloft, gradually spreading eastward early next week and helping to moderate temperatures in the Plains by midweek. Temperatures could reach around 10 degrees above normal in the East ahead of the trough Wednesday-Thursday. 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, 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 $$