Widespread Heavy Rain Raises Flash Flood Risk From Utah to Maine

Overview

• WPC identified a corridor from eastern Tennessee into southern Virginia and northern North Carolina where storms could produce hourly rates above 2 inches and localized 2–4 inch rain stripes that may trigger flash flooding.
• WPC also warned that Utah and western Colorado face a likely flash-flood event because precipitable water is in the 95th–99th percentile and slow-moving storms can drop 1–2 inches per hour with isolated totals above 3 inches, especially over burn scars.
• SPC flagged a growing severe threat in much of Maine with about a 40 percent chance a watch will be needed and noted an isolated damaging-wind or brief tornado risk in parts of the Mid-Atlantic though watch issuance there appears unlikely.
• Forecasters say short-range models show very high short-duration rainfall but disagree on exact storm placement and speed, so mesoscale uncertainty means impacts will be highly localized and local NWS offices will issue targeted warnings.
• People in the affected zones should expect rapid runoff and sudden rises on small streams and roads, follow local Weather Forecast Offices and River Forecast Centers for warnings, and avoid driving through flooded water as conditions evolve.