193 FXUS02 KWBC 100725 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 325 AM EDT Sat Oct 10 2026 Valid 12Z Tue Oct 13 2026 - 12Z Sat Oct 17 2026 ...Heavy rainfall threat continues into the Intermountain West early next week... ...Record heat for the Southern Plains, Mid-South, and Southeast... ...Overview... Upper troughing over the West early next week will be a combination of northern stream energy that drops down the West Coast and remnant energy and moisture of what is currently Tropical Storm Rachel as it moves into the Southwest U.S. this weekend. Anomalous moisture with this system will continue to bring a flash flooding threat across portions of the Intermountain West into the start of the medium range period on Tuesday. Meanwhile, moisture from ex- Simon will stream northward, with an expanding area of rain over the Central U.S. as the western trough drifts slowly eastward. Another shortwave out of Canada should drop down and likely pull at least some of this western U.S. energy eastward with troughing becoming established over the East by late period. Strong upper ridging over the south-central to Southeast early in the period should allow for much above normal to record-setting warm temperatures early to mid week, slowly moderating with time. ...Guidance/Predictability Assessment... Model guidance continues to show reasonably good agreement early in the forecast period with a positively tilted trough/upper low located over southern Nevada by early Tuesday, slowly drifting east-northeastward into Wednesday. After this, the evolution becomes increasingly uncertain as additional shortwave energy from southwest Canada begins to interact with this feature. The GFS and EC-AIFS (and yesterdays 12z CMC) show the western low getting picked up by this energy racing it eastward and amplifying troughing over the East by next weekend. The ECMWF, UKMET, and now the new 00z CMC show less phasing with these systems allowing the upper low to meander longer over the West and weakening before possibly getting absorbed into the next trough into the Northwest next Saturday. This also results in a much faster and less amplified trough over the East late period. Recent AI-GFS runs continue to be incredibly strong with diving the southwest Canada northern stream energy farther south into the West, which still seems like an outlier. With the new 00z guidance tonight, there may be some slight trend towards wanting to hold back energy for longer over the West, as suggested primarily by the ECMWF, UKMET, and 00z CMC. Despite this, the WPC forecast trended more towards the ensemble means late period, amidst significant uncertainty. This shows a bit faster progression of the low, closer to the GFS, but it is also consistent with previous WPC continuity which seems safer until a more consistent slower trend emerges. ...Weather/Hazards Highlights... Across the West, the remnants of Rachel combined with the incoming upper trough will yield additional widespread modest to locally heavy rainfall and localized flash flooding into the Great Basin on Tuesday. See the Excessive Rainfall Outlook for more information. Cold air surging behind the cold front will lower snow levels, leading to accumulating snow over higher elevations of the West. This could be the first appreciable snow for the Utah ranges. Snow is possible in portions of the Northern/Central Rockies as well Tuesday-Wednesday and perhaps lingering into Thursday. As the low pressure system lifts into the Northern Plains, moisture from what is leftover from Simon may stream northward and aid in producing a widespread area of rain in the central U.S. Tuesday-Wednesday. Thunderstorms, including potential severe weather, are likely in the Southern/Central Plains to Lower/Middle Mississippi Valley ahead of the associated cold front, which could linger into Thursday. Farther north, rain is likely to be more progressive, spreading across the Northern Plains to Upper Midwest on Wednesday and the Great Lakes/Ohio Valley/Northeast by Thursday and Friday. The surface low strengthening in the Midwest/Great Lakes while a cold surface high drops into the Rockies could lead to high winds in the Dakotas and vicinity by Thursday and especially Friday. Elsewhere, a round of rain is possible in the Great Lakes to Northeast on Tuesday with a shortwave aloft and a cold front. Ahead of the front, temperatures in the southern Plains to the Southeast will be well above normal and likely set new daily high temperature records (upper 80s to the mid 90s). Low temperatures may only fall into the 70s for several nights, with the combination yielding widespread Moderate HeatRisk and perhaps reaching Major over south Texas. The warmer temperatures in the 90s will gradually cool back into the 80s as fronts approach. Meanwhile the upper troughing in the West will bring broadly below average temperatures there through Tuesday, along with frost/freeze threats. Additional chilly air may come into the Northern Rockies and vicinity late week, with northwest flow aloft and surface high pressure. Upper ridging Friday into Saturday over the Northwest should help moderate temperatures back towards or slightly above normal. Santorelli/Tate 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 $$