645 FOUS30 KWBC 100808 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 408 AM EDT Fri Apr 10 2026 Day 1 Valid 12Z Fri Apr 10 2026 - 12Z Sat Apr 11 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS... A west-east orientated frontal boundary will be dropping southward through the period while PW values of +2-2.5 standard deviations advect northward across the region as the low level flow strengthens. Meanwhile, shortwave energy pushing northeastward into this high PW axis in the vicinity of this front will support areas of slow moving convection along this front, locally heavy rains and isolated runoff issues. HREF neighborhood probabilities show 40-70% for 2 inches and 20-40 % for 3 inches of rainfall across these areas. While areal averages are generally expected to be less than 1.5 inches, there are signals for isolated maximums of 3-4+ inches per the latest CAM guidance. The Marginal Risk area for excessive rainfall was maintained from the Oklahoma/Texas Panhandles to southwest Missouri. Campbell Day 2 Valid 12Z Sat Apr 11 2026 - 12Z Sun Apr 12 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE SOUTHERN PLAINS... Gulf moisture will continue to advect northward with PW anomalies surging to +3 deviations above seasonal normal across the Plains. Upper dynamics will support ascent ahead of a longwave trough entering the West Coast, as well as a shortwave trough traversing the High Plains. As ridging builds in across the east, this will also promote strong southerly flow and a low level jet over the Southern Plains and Texas to advect moisture and instability in the area. At the surface, a dry line across West Texas will help serve as an initiating mechanism for convection. The latest guidance continues to depict a signal for 2-4 inches possible from the Concho Valley in West Texas to the Red River Valley in southern Oklahoma. Rainfall rates could also be as high as an inch or two per hour with organized convection likely as noted with SPC's Slight Risk across the region. WPC maintained the Slight Risk for excessive rainfall from the West Texas/Hill Country northeast to the Red River Valley. A Marginal extends from the Rio Grande to southeast Kansas. Campbell/Wilder Day 3 Valid 12Z Sun Apr 12 2026 - 12Z Mon Apr 13 2026 ...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY... Multiple rounds of strong to severe storms will persist across the Southern/Centrals Plains and Lower Mississippi Valley given favorable wind shear and instability in place. Moisture transported northward from the western Gulf to the Midwest between the eastern U.S. upper ridge and the trough over the Rockies will maintain enhanced rainfall. And with limited eastward progression of the QPF footprint expected during this period, it will keep an elevated threat for local flash flooding concerns. A Marginal Risk remains in effect from central-eastern Texas to southeast Kansas/southwest Missouri. Campbell Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt