WPC Warns Of Widespread Flash‑Flood Risk From Intense Short‑Term Downpours

Overview

• The Weather Prediction Center issued multiple mesoscale precipitation discussions and regional offices reported that heavy convective bands produced extreme local totals, with radar‑based estimates showing 4 to 6 inches of rain in parts of southeast Minnesota.
• Saturday's heavy storms produced very high short‑term rates, with guidance and observations showing pulses as large as 1 to 2.5 inches per hour that supported repeated cell‑training and back‑building over vulnerable areas.
• Forecasters cited a strong northward plume of subtropical moisture, elevated precipitable water values well above normal, enhanced low‑level jets, and midlevel shortwave energy as the drivers that increased rainfall efficiency and persistence.
• The greatest flash‑flood threat is concentrated across the Four Corners and much of NM/AZ, portions of UT/ID/WY, the Plains and Upper Midwest, with burn scars, arroyos, narrow canyons and urban impervious surfaces singled out as highest risk locations.
• High‑resolution models (HRRR, HREF, WoFS) and MRMS radar‑QPE continue to show uncertainty in exact storm placement but indicate the potential for additional localized multi‑inch accumulations overnight that could trigger more rapid runoff and life‑threatening flooding.