999 FXUS02 KWBC 160827 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 427 AM EDT Fri Oct 16 2026 Valid 12Z Mon Oct 19 2026 - 12Z Fri Oct 23 2026 ...A possible East Coast low early-to-mid next week could bring coastal impacts... ...Overview... A developing coastal low could produce rain and wind hazards along the Mid-Atlantic Coast early-to-mid next week. A digging trough in the West is expected to produce a cut-off low, which could tap tropical moisture and generate heavy rainfall and mountain snow over portions of the Four Corners, Sierra Nevada, Southern Plains and Great Basin next week. ...Guidance/Predictability Assessment... The deterministic GFS appears to be coming into alignment with the Euro regarding a mid-level disturbance that lingers behind its parent trough and restrengthens over the Carolina Coast early next week. All other deterministic guidance have some mid-level feature present, but the strength of the low remains the main question. Cluster analysis signals that the predominant area of uncertainty in the 500mb pattern across the CONUS during the medium range is the timing/placement of a digging East Pacific cut-off low. The speed at which this system propagates east will determine how much precip portions of the Southwestern U.S. get beginning early next week. ...Weather/Hazards Highlights... A coastal low is expected to develop off the Carolina coast later this weekend. The current trends suggest more rain and winds along portions of the Mid-Atlantic and Northeast Coasts. High winds hazards are currently likely from the North Carolina Coast up to the Delaware Coast. Temperatures across the East Coast are forecast to be average to slightly below average, but could wind up being colder than forecast if current trends continue and the coastal low strengthens and/or gets closer to the coast. 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 mid-level disturbance will break off from a Gulf of Alaska low and dig/amplify into a cut-off low over the Eastern Pacific/Western U.S. on Tuesday or Wednesday. 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. 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 $$