Weather
Southwest Weather Oct. 10-12: Tropical Rain Saturday to Monday
Southwest U.S. – Locally heavy rainfall could trigger flash flooding across portions of the southwestern United States Saturday through Monday, Oct. 10 12, as tropical moisture associated with Tropica
By Cameron Hayes · 2026-10-09T12:27:03.420Z
Southwest U.S. – Locally heavy rainfall could trigger flash flooding across portions of the southwestern United States Saturday through Monday, Oct. 10 12, as tropical moisture associated with Tropical Storm Rachel spreads from Southern California toward Utah.
According to NOAA's Weather Prediction Center, the approaching tropical moisture will create a multiday flash flood threat across parts of Southern California, Arizona, Nevada and Utah.
The Weather Prediction Center's excessive rainfall outlook identifies areas of both Marginal Risk and Slight Risk during the three day period, indicating varying probabilities of rainfall exceeding local flash flood guidance.
Saturday, Oct. 10, the flash flood threat will focus on portions of Southern California and western Arizona. A Slight Risk area is highlighted within a broader Marginal Risk zone, indicating an elevated potential for excessive rainfall in the affected locations.
By Sunday, Oct. 11, the threat is forecast to expand northward and eastward, with portions of Arizona and neighboring states facing increased chances of heavy rainfall.
The outlook shows another Slight Risk area Sunday, surrounded by a larger Marginal Risk region.
Monday, Oct. 12, the excessive rainfall threat shifts farther north into portions of Utah and surrounding areas, with a corridor of Slight Risk extending through parts of the interior Southwest.
Under the Weather Prediction Center's risk categories, a Slight Risk indicates at least a 15% chance of rainfall exceeding flash flood guidance within 25 miles of a point. A Marginal Risk represents at least a 5% chance.