Overview

• The NWS Weather Prediction Center says isolated to scattered flash flooding is likely this afternoon from central and northern Arizona into southern Utah, with hourly rates often near 0.5 to 1 inch and locally higher where storms train.
• Forecasters expect storms to develop and expand over southern California, southern Nevada and into central Utah over the next 3 to 6 hours, producing 0.5 to 1.5 inches of rain in an hour and at least isolated flash flooding.
• Earlier this morning, WPC highlighted southern and central Arizona for isolated flash flood potential as north‑northeastward‑moving convection persisted.
• The setup features unusually high precipitable water values running roughly 3 to 5 standard deviations above normal, pockets of 500–1000 J/kg CAPE, and unidirectional southwesterly flow that favors repeating cells.
• Greatest concerns focus on slot canyons, small streams, normally dry washes, burn scars and urban low‑lying areas, while the SPC notes a low‑probability risk for isolated severe hail or wind in parts of southern Nevada and adjacent areas.