Slow‑Moving Storms Raise Flash‑Flood and Severe‑Storm Risks Across Multiple U.S. Regions

Overview

• National Weather Service centers say ongoing bands of slow‑moving thunderstorms are producing isolated flash flooding and pockets of severe hail and damaging wind late Friday into the overnight hours.
• WPC Mesoscale Precipitation Discussions highlighted hotspots for flash flood risk in the Lower Mississippi Valley, Tennessee Valley, Southeast, eastern Montana, and the Pacific Northwest with potential hourly rain rates commonly 1–2 inches and isolated 3+ inch reports.
• SPC issued Severe Thunderstorm Watch 251 for parts of west and northwest Texas and multiple mesoscale discussions for the Plains and Rockies, citing threats of large hail up to 2 inches and damaging gusts to about 70 mph with observed gusts near 68–70 mph.
• Forecasters point to saturated soils from repeated May storms, very high atmospheric moisture (precipitable water often 1.6–2.2 inches), and strong instability (MLCAPE often 1,000–3,000 J/kg) as the reasons storms can train, stall, or produce intense cores.
• Residents in flagged counties should monitor local NWS warnings and avoid flooded roads because slow motion storms can produce sudden flash floods and localized wind or hail damage that may persist into the night.