Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
319 FXUS02 KWBC 020647 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 147 AM EST Mon Nov 2 2026 Valid 12Z Thu Nov 05 2026 - 12Z Mon Nov 09 2026 ...Overview... Unsettled weather continues for portions of eastern U.S. as the upper trough and associated frontal system continues to progress toward the eastern seaboard. Behind the frontal system, cooler and drier conditions will expand from central U.S. into much of eastern U.S. behind the front. However, lingering upper-level energy and moisture associated with a northward lifting western Atlantic low may maintain periods of unsettled weather near the East Coast through the weekend. Across western U.S. additional Pacific disturbances may bring precipitation chances into the Pacific northwest. ...Guidance/Predictability Assessment... The latest model guidance indicates improving agreement on the broad evolution of the amplified eastern U.S. trough and the eastward movement of the associated frontal system through the first half of the period. However, uncertainty remains with the timing and and amplitude of individual shortwaves and the potential interaction between the western Atlantic surface low. These difference are important across the Mid-Atantic and Northeast, where the degree of interaction with the low could determine whether precipitation ends relatively quickly behind the front or lingers into the weekend. Across western U.S., the evolution of the Pacific disturbances remains uncertain as well. Individual model solutions differ in the timing and strength of the incoming disturbance, but the broader signal supports continued periods of onshore flow and precipitation across the Pacific Northwest. Furthermore, chances for showers and thunderstorms across portions of the southern tier will also depend on the eastward progression of the western trough and the transport of Pacific moisture. Given these uncertainties, a multi-model blend were used in the forecast, with heavier weight on the ensemble means towards mid-period. ...Weather/Hazards Highlights... The primary upper trough and associated frontal system will continue progressing eastward from the Tennessee and Ohio Valleys towards the Appalachians and eastern seaboard. Strong south to southwesterly low-level flow ahead of the boundary will transport Gulf moisture northward, supporting widespread showers and thunderstorms across portions of the Southeast, Mid-Atlantic, and Northeast. There is some uncertainty along the East Coast as the primary frontal boundary pushes offshore and the western Atlantic low moves northeastward by late week into the weekend. Depending on the track and interaction with frontal boundaries, additional moisture could support lingering showers across portions of coastal Mid- Atlantic and Northeast. Furthermore, high pressure begins to build behind the front, allowing for drier conditions to spread across much of central and eastern U.S. Across western U.S., additional Pacific disturbances will approach the Pacific Northwest by late week and will maintain periods of precipitation along the coast and over the Cascades. Some low elevation rain may extend inland across the northern Intermountain West/Rockies, with higher elevations favoring snow. Further south, a southern stream troughing pattern, with additional shortwave energy is expected to move through the Southwest/Four Corners, which may support showers across portions along the Four Corners Region/Rockies and central Plains. 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 $$