Widespread Flash Flood Threat From Training Storms Across Central and Southern U.S.

Overview

• The NWS Weather Prediction Center issued multiple mesoscale precipitation discussions on Saturday warning of heavy rain and flash‑flood risk across the Midwest, Ohio/Tennessee Valleys, Southeast, Texas Hill Country and parts of New Mexico.
• Forecasters said very high precipitable water values support rainfall rates commonly exceeding 1.5 inches per hour with corridors expected to receive 2–4 inches and isolated 5+ inch totals where storms train or backbuild.
• The Storm Prediction Center flagged an overlapping severe threat for portions of southern Indiana, Ohio, central Kentucky and middle Tennessee, saying organized clusters and a few supercells could produce damaging gusts and isolated tornadoes with a watch about 40 percent likely.
• Urban centers such as Chicago and Nashville, recent burn scars, slot canyons and small basins were singled out as most vulnerable because saturated soils and recent heavy rains lower the amount of rain needed to cause flash flooding, prompting local warnings and possible watches.
• High-resolution models disagree on exact storm placement so forecasters stressed observation-driven updates and cautioned that persistent training could quickly flood streets, overwhelm drainage systems and raise small-stream and river levels over the next several hours.