Severe Hail, 80+ Mph Winds and Flash Flooding Threaten Multiple U.S. Regions

Overview

• The NWS Storm Prediction Center issued multiple watches Saturday night into Sunday for the northern and High Plains, including Severe Thunderstorm Watches 408 and 410 and Tornado Watch 406, warning of very large hail, damaging gusts to about 80 mph and isolated tornadoes.
• Forecasters say strong mesoscale drivers — convectively generated MCVs, outflow boundaries and a strengthening nocturnal low‑level jet — are repeatedly focusing storms and enabling backbuilding and training that make impacts highly localized and fast changing.
• The Weather Prediction Center issued mesoscale precipitation discussions for the Ohio and Mid‑Mississippi valleys that warned of locally extreme rainfall rates, training storms and saturated soils that create a continuing life‑threatening flash‑flood risk.
• Several initially discrete supercells have upscaled into organized MCSs and bowing segments, shifting the primary hazard from isolated very large hail to widespread damaging straight‑line winds while preserving a corridor of tornado potential.
• Local NWS offices, River Forecast Centers and real‑time SPC/WPC products are the primary sources for watches, warnings and flood statements because small shifts in storm placement will determine where the worst wind, hail or flash flooding occurs.