Snow Showers and Strong Winds Across the Great Lakes and Northeast

Storm Map: Heavy Storms and Flash Flooding Across the Southwest

Valid Wednesday, October 21, through Friday morning, October 23, 2026

A Significant Southwestern Storm Pattern

A potentially impactful storm system is expected to bring periods of heavy rain, thunderstorms, and localized flash flooding across portions of the Southwest from today into Thursday. The greatest concern is centered on Arizona, including the Phoenix and Tucson areas, where the storm map highlights an elevated risk of severe storms and flooding. Additional areas of concern extend into southern Nevada, southeastern California, and portions of Utah and western New Mexico.

Moisture interacting with an approaching weather system could produce locally intense rainfall over a relatively short period. Some locations may receive 1–3 inches of rain in a short time, which could overwhelm drainage systems and produce dangerous runoff, especially in areas that are not accustomed to handling heavy rainfall.

Arizona: The Greatest Concern

Arizona is the primary area of concern on this outlook. The highlighted risk zone covers a broad portion of the state, including Phoenix, Tucson, Flagstaff, Prescott, and surrounding communities.

Thunderstorms could produce intense downpours, localized flash flooding, and damaging wind gusts. Blowing dust may also develop in areas where strong winds lift loose, dry soil, particularly ahead of storms or along their outflow boundaries.

The risk will not be uniform across the state. Some communities may experience brief but intense thunderstorms, while others receive considerably less rainfall. However, where storms repeatedly affect the same locations, rainfall could accumulate quickly and create hazardous conditions.

Southern Nevada and Southeastern California

Southern Nevada, including the Las Vegas region, is also within the highlighted severe-storm risk area. Heavy downpours could lead to rapid runoff through washes, normally dry channels, and low-lying areas.

Across southeastern California and nearby desert communities, scattered thunderstorms could bring periods of heavy rain and gusty winds. Even a relatively brief storm can create dangerous conditions in desert terrain, where water can collect rapidly in washes and narrow drainage channels.

Motorists should remain alert for sudden reductions in visibility from blowing dust and avoid traveling through flooded roadways.

Utah and Western New Mexico

Areas of Utah and the Four Corners region are included in the moderate heavy-rain risk zone. Localized rainfall could produce flash flooding in poor-drainage areas, mountain canyons, and locations vulnerable to runoff.

Western and central New Mexico may also experience periods of showers and thunderstorms, with locally heavy rainfall possible near the edge of the main risk area. The coverage and intensity of storms will depend on how moisture and atmospheric disturbances evolve through Thursday.

Main Hazards to Watch

• Flash flooding: Locally heavy rainfall, potentially reaching 1–3 inches in a short period, could cause rapid water rises.

• Damaging winds: Strong thunderstorm gusts may affect exposed areas and produce isolated damage.

• Blowing dust: Gusty winds could sharply reduce visibility across desert areas.

• Dangerous runoff: Washes, arroyos, mountain canyons, and low-water crossings may become hazardous with little warning.

The Bottom Line

The period from Wednesday into Thursday brings a notable storm and flooding concern across the Southwest, with Arizona standing out as the primary area to watch. Southern Nevada, southeastern California, Utah, and western New Mexico could also experience locally heavy rainfall and thunderstorms.

The exact placement of the heaviest rain will depend on individual storm development, but isolated areas could receive substantial rainfall in a short period. Residents should monitor changing conditions and heed local warnings.

Turn around, don't drown. Never drive or walk through floodwater. Desert washes and normally dry channels can become dangerous very quickly, even when heavy rain is falling some distance away.