Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 22 2025 08:30:35 FOUS30 KWBC 220830 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 430 AM EDT Wed Oct 22 2025 Day 1 Valid 12Z Wed Oct 22 2025 - 12Z Thu Oct 23 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 2 Valid 12Z Thu Oct 23 2025 - 12Z Fri Oct 24 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Hurley Day 3 Valid 12Z Fri Oct 24 2025 - 12Z Sat Oct 25 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHERN PLAINS INTO THE WESTERN OZARKS... ....Southern Plains into the Western Ozarks... Models continue to amplify the mid/upper trough across the southern Rockies-southern High Plains Sat-Sat night as a subtropical jet streak rounds the trough base. Meanwhile, the northern stream jet streak begins to curve across the central Plains-Mid MS Valley, which within a broad right entrance region, would couple with the increasing southern stream forcing and thus lead to a fairly sizable area of robust deep-layer lift and low-level moisture transport. TPWs climb between 1.5 to 2.0" from north-south across the outlook areas. which is around 2 standard deviations above normal for late Oct. Meanwhile, increasing south-southwesterly low level flow (35-40+ kts at 850 mb) will begin to align with while=20=20 reach the same magnitude of the mean 850-300 mb flow during the=20 period, as the upper trough amplifies and approaching surface front slows down. This will favor a higher likelihood of multiple linear convective segments ahead of the front, with cell training most likely within the Slight Risk area.=20 Guidance shows pockets of 3-6+ inches of rain within the Slight=20 Risk area, particularly across North TX into central-northeast OK. There is still some areal-spread however with respect to the heaviest totals. Furthermore, the dry antecedent conditions -- low soild moisture percentiles from NASA SPoRT and high FFG values from the RFCs -- combined with the model ....Pacific Northwest into Northwest California... The Marginal Risk area from yesterday's Day 4 ERO was modified only slightly for today's Day 3 ERO. Modest Atmospheric River (AR), level 3 on a 5-level scale per the Center for Western Weather and Water Extremes (CW3E), will push across the coastal and Cascade ranges over WA/OR Friday, then into the northwest CA coastal and Shasta/Siskiyous late Fri and Friday night. IVT values peak around 700-750 Kg/m/s, however only for a brief period of time at any given location as the AR is rather transient (steady southward=20 progression). Guidance is in fairly good agreement with the QPF amounts, averaging 2-4" across the outlook area, with local totals of 5+ inches. Much of this would fall within 12 hours as the AR traverses the area, with peak rates near 0.50"/hr along and near=20 the axis of maximum TPW (1.00-1.25") with some (albeit weak) elevated instability (MUCAPEs ~100-200 J/Kg). This rainfall may induce some localized short-term runoff issues, particularly in more urban/poor drainage areas and over burn scars. Hurley Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!4cOU377KuUnFhoXL2XTj2QxfIBtZ-zYqh014RIS8rWZX= vdlgBCxPfAd0rvbIWoiCVEwHiXrhnE6wrx2whwqV6buT3AA$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!4cOU377KuUnFhoXL2XTj2QxfIBtZ-zYqh014RIS8rWZX= vdlgBCxPfAd0rvbIWoiCVEwHiXrhnE6wrx2whwqVskIZsco$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!4cOU377KuUnFhoXL2XTj2QxfIBtZ-zYqh014RIS8rWZX= vdlgBCxPfAd0rvbIWoiCVEwHiXrhnE6wrx2whwqVkQleH20$=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .