308 FXUS21 KWNC 131853 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT October 13 2026 SYNOPSIS: Multiple model ensembles depict a robust storm developing in the lee of the Rockies late in week-1, which is favored to produce potentially hazardous heavy precipitation for much of the Plains and Mississippi Valley early in week-2. Models also favor below-normal temperatures across the West, which may interact with enhanced moisture from the tropical Eastern Pacific and the developing storm resulting in potentially heavy snow for portions of the Central and Northern Rockies early in the forecast period. HAZARDS Moderate risk of heavy precipitation for portions of the Southern Plains and Lower Mississippi Valley, Wed-Thu, Oct 21-22. Slight risk of heavy precipitation for much of the eastern Great Plains and the Mississippi Valley, Wed-Fri, Oct 21-23. Slight risk of high winds for much of the Northern and Central Plains, and Upper and Middle Mississippi Valley, as well as northern portions of the Southern Plains and Lower Mississippi Valley, Wed-Thu, Oct 21-22. Slight risk of heavy snow for portions of the Northern and Central Rockies, Wed-Thu, Oct 21-22. DETAILED SUMMARY FOR FRIDAY OCTOBER 16 - TUESDAY OCTOBER 20: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR WEDNESDAY OCTOBER 21 - TUESDAY OCTOBER 27: Models continue to indicate the potential for a robust lee cyclogenesis event occurring over the Great Plains starting late in the week-1 period, while indications of the potential for hazardous weather has seen an uptick relative to yesterday. Consensus among multiple model ensembles depicts widespread precipitation over the Great Plains by day-8 (Oct 21) as a wide surface trough stretches across the central Contiguous U.S. (CONUS) with mid-level troughing over the spine of the Rockies. Model solutions move this surface low east quickly while the mid-level trough quickly loses strength as it interacts with ridging over the eastern CONUS for much of the forecast period, thus the largest potential for impactful weather looks to be front-loaded with this system. A variety of forecast tools indicate the potential for precipitation to exceed hazardous levels early in week-2. Uncalibrated probabilities from the GEFS and ECENS both exceed 20% for 3-day precipitation totals to exceed 2 inches over portions of the Arklatex region, and 30-40% chances for exceeding 1 inches across much of the Plains and Mississippi Valley. The Probabilistic Extremes Tools are also supportive, with at least 20% chances of 3-day precipitation to exceed the 85th climatological percentile across the central CONUS and higher probabilities further south, exceeding 60% over the Southern Plains in the ECENS PET. Given all this, a moderate risk of heavy precipitation is posted for the eastern Southern Plains and much of the Lower Mississippi Valley valid Oct 21-22. A slight risk of heavy precipitation is also posted for most of the Mississippi Valley and eastern Great Plains for the period Oct 21-23. No areas are currently highlighted for flooding potential at this time, but with the potential of heavy precipitation also comes the potential for isolated flooding and flash flooding, and caution should always be exercised around flowing water of unknown depth. Model solutions spin up the surface low very close to the Front Range of the Rockies, favoring unsettled weather along the Northern and Central Rockies before the system moves away from the mountains. Continued tropical cyclone (TC) activity in the Eastern Pacific tropics has the potential to bring a moisture surge into the Great Basin as well, potentially bringing heavy snow to portions of the Northern and Central Rockies. The ECENS is very bullish, with uncalibrated probabilities exceeding 20% for 3-day snowfall totals to exceed 6 inches throughout the week-2 period. The GEFS is much more circumspect, indicating a similar signal strength at the 4-inch threshold early in week-2, then little signal after. Regardless of this discrepancy, pattern recognition as well as snow climatology suggest hedging towards the ECENS solution, therefore a slight risk of heavy snow remains for portions of the Northern and Central Rockies for Oct 21-22. Surface gradients associated with this system start off quite strong with a negative-tilted trough, favoring enhanced winds over much of the country's midsection. The PETs from the GEFS and ECENS reflect this, indicating at least a 20% chance of 3-day maximum winds to exceed the 85th percentile over much of the north-central CONUS early in the forecast period, and isolated areas exceeding 25mph early in week-2. Therefore, a slight risk of high winds is posted for much of the Northern and Central Plains, and the Lower and Middle Mississippi Valley for Oct 21-22. Model solutions depict persistent troughing at the surface and aloft over the Alaska region throughout the forecast period. While this is likely to result in strong winds and heavy precipitation, hazards thresholds are not expected to be exceeded so no hazards are posted at this time. FORECASTER: Danny Barandiaran $$