413 FXUS02 KWBC 060605 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 205 AM EDT Tue Oct 6 2026 Valid 12Z Fri Oct 09 2026 - 12Z Tue Oct 13 2026 ...Excessive rainfall/flash flood threat continues for portions of the Gulf Coast and Southeast through this weekend... ...Guidance/Predictability Assessment... The latest model guidance continues to show agreement with the mean trough over eastern U.S. gradually pushing offshore, while the western trough moves inland. The highest uncertainty remains with the western trough, especially when the solutions diverge towards Sunday. Deterministic models show that depending on the eventual position and strength of the cutoff low over the Northwest, periods of rain and mountain snow can persist into early next week across the Northwest and northern Rockies. Ensemble means solution tends to avoid emphasizing a highly specific evolution and smooth some of the extreme precipitation amounts. Therefore, continued use of the ensemble means and multi- model blend is favored to limit sensitivity to individual deterministic solutions. ...Pattern Overview and Weather/Hazards Highlights... The broad troughing across eastern U.S. will begin to push offshore through the weekend, while a more complex split-flow regime develops over the West. The most significant rain threat through the weekend will be across the Gulf Coast into the Southeast as a slow-moving frontal boundary remains stretched across the Southeast/Gulf Coast. The disturbance lifting northeastward from the Gulf will encounter abundant moisture and sufficient instability, leading to enhanced rainfall rates along the frontal boundary. Locally flash flooding will be possible over areas that will receive repeated convection. This is highlighted with a Slight Risk in the WPC Excessive Rainfall Outlook Day4/Friday for portions of the Gulf Coast. The frontal boundary will continue to lift northeast through the weekend, shifting the axis of heavier rainfall towards portions of Ohio/Tennessee Valley and Mid- Atlantic by Saturday. Therefore, the Slight Risk expands further north into portions of the Southeast for Day5/Saturday, while a Marginal covers portions of the Tennessee Valley. Showers will continue to extend further north across portions of the Northeast by Sunday. Across the West, the weakening ridge and developing upper trough will bring a significant weather pattern change. Temperatures across Pacific Northwest into northern Plains will transition to below normal temperatures through the weekend into early next week. Additionally, moisture combining from Tropical Cyclone Rachel and the Pacific trough will bring an increase in precipitation chances across much of western U.S. starting with the Northwest on Friday then eventually spread across the Intermountain West, Rockies, and Southwest through the weekend. As the upper low becomes more established, rainfall amount should increase through the weekend. Furthermore, snow levels will lower with the arrival of colder air, which may lead to heavy to moderate mountain snow. By late Sunday into Monday, the frontal boundary will support showers expanding across the Plains into the Upper Midwest. Oudit 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 $$