Severe Storm Watches and Flash‑Flood Threats Spread From Arizona to the Mid‑Atlantic

Overview

• The Storm Prediction Center issued Severe Thunderstorm Watch 538 for southeast Arizona on Tuesday for storms capable of damaging wind gusts to about 70 mph and isolated 1‑inch hail while Severe Thunderstorm Watch 537 continued to cover parts of north‑central Minnesota where brief tornadoes or damaging gusts remained possible.
• The Weather Prediction Center flagged localized flash‑flood risk across many areas including northern Missouri into southern Iowa and western Illinois, central and southern Iowa, parts of the Plains and Midwest, the I‑95 corridor from Washington/Baltimore through Philadelphia, coastal Carolinas, and sections of Georgia and the southern Appalachians.
• Meteorologists warned that storms in the most vulnerable zones can produce very high short‑term rates of rainfall — commonly 1–2 inches per hour with isolated 1.5–3+ inch bursts and spot totals of 2–4+ inches — driven by training or slow‑moving cells.
• Forecasters say the pattern is driven by high precipitable water values, monsoonal and tropical moisture surges, and weak steering winds that favor backbuilding; real‑time guidance from HRRR, RRFS, WoFS and MRMS is being used to target short‑notice warnings from local NWS offices and River Forecast Centers.
• Residents in urban areas, recently drenched basins and low flash‑flood‑guidance locations should expect rapid runoff, localized flooding and travel disruption and should monitor warnings from local NWS offices for imminent severe‑storm or flash‑flood statements.