163 FXUS02 KWBC 162017 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 417 PM EDT Fri Oct 16 2026 Valid 12Z Mon Oct 19 2026 - 12Z Fri Oct 23 2026 ...A nor'easter could bring prolonged impacts to coastal communities along the East Coast... ...Overview... A developing nor'easter could be slow to exit the East Coast, bringing prolonged rain, wind, and wave hazards along the Mid- Atlantic Coast potentially extending into late next week. A digging trough off the West Coast is forecast to evolve into a cut-off low, which could tap tropical moisture and generate heavy rainfall and mountain snow over portions of the Great Basin, Four Corners, Sierra Nevada, and eventually emerge into the High Plains late next week. ...Guidance/Predictability Assessment... The AI models led the way a couple of days ago in indicating the possibility of a significant nor'easter through the middle of next week off the East Coast. The dynamical ECMWF later indicated the potential for the nor'easter to acquire tropical characteristics over the above normal warm waters near the Gulf Stream. It took a couple more runs for the GFS to suggest the possibility of a nor'easter. Since yesterday, all dynamical models have followed suit to indicate coastal cyclogenesis closer toward the East Coast by early next week. While the guidance shows a variety of forward motion of the nor'easter thereafter, ranging as far south as Florida to making landfall at the Mid-Atlantic coast, the average of all ensemble possibilities suggest little overall motion somewhere just off the North Carolina coast, with wind and wave impacts possibly lingering along the Mid-Atlantic coast into late next week. Over the western U.S., model consensus has trended toward a slower eastward progression for the deep trough to dig offshore from the West Coast next week before pushing into the western U.S. later next week. The progression has now been delayed so that rain is now forecast to hold off across the High Plain until late next week, possibly till Friday for the northern High Plains. ...Weather/Hazards Highlights... A nor'easter is forecast to develop off the Carolina coast later this weekend. Rain associated with the system has trended more inland in this latest cycle, with wind possibly reaching gale force as far west as the southern portion of the Chesapeake Bay. High wind hazards are currently likely from the North Carolina Coast up to the Delaware Coast, which could extend further up the Atlantic coast toward Long Island at times into late next week. Temperatures across the East Coast are forecast to be normal to slightly below normal, but could wind up being colder than forecast if current trends continue. An upper ridge, aided by an amplifying upstream pattern and approaching embedded shortwave energy, will support broad southerly flow and above average temperatures across the central U.S. next week. The embedded shortwave doesn't carry a threat of producing any precipitation. A shortwave passing south of the Gulf of Alaska is forecast to dig/amplify into a cut-off low over the eastern Pacific just off the West Coast midweek. The depth and speed of this system will determine how much moisture it can pull into the region. The latest trends suggest an increasing likelihood for anomalous moisture to be pulled into the West. This moisture will then interact with a strong cold front and produce scattered to isolated thunderstorms over portions of the Four Corners. Heavy rainfall may occur as well with some Extreme Forecast Index shift of tail signals showing up across the Southwest by next Tuesday night. Some high elevation snowfall can't be ruled out for parts of the Intermountain West and Sierra Nevada by mid-week. Kong/Kebede 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 $$