Rachel Brings Flood Risks and Cooler Temperatures to Arizona

Arizona faces a multiday period of heavy rain, strong winds and falling temperatures as moisture from Tropical Storm Rachel moves into the state from Saturday, October 10, through Tuesday, October 13. Forecasts from the National Weather Service and local meteorologists warn of flash flooding, isolated thunderstorms and hazardous driving conditions, particularly across northern and western Arizona.

According to azcentral.com, the greatest potential for widespread rainfall is Saturday afternoon through Sunday morning, October 10–11. Additional scattered showers and thunderstorms could develop Monday and Tuesday as another low-pressure trough influences the region after Rachel moves away.

Flood watches will cover parts of northwestern Arizona and the Mogollon Rim, with alerts for Mojave, Yavapai, western Coconino, northern Gila and far southern Navajo counties scheduled from 11 a.m. Saturday until 5 a.m. Monday. The National Weather Service warns that excessive runoff could affect rivers, creeks, streams, urban areas and other flood-prone locations.

The Weather Prediction Center has assigned western Mohave County a 40% risk of flash flooding for Sunday, while western Arizona faces a 15% risk. Forecasts indicate that numerous to scattered flash floods are possible in the affected areas.

According to azcentral.com, Yavapai, Coconino and Mohave counties could receive 1 to 3 inches of rain. In the Phoenix metropolitan area, projected rainfall ranges from a quarter of an inch to 1.50 inches, with locally higher totals possible. ABC15 separately forecasts that some Valley locations could receive between half an inch and 1 inch through Tuesday.

Officials also warn that water may accumulate in normally dry washes, creeks, swimming holes and recently burned areas. Low-water crossings could become dangerous or impassable, and drivers should never attempt to cross flooded roads.

Wind advisories will cover nearly the entire state on Sunday, with Graham, Greenlee and Cochise counties excluded from the advisory areas described by azcentral.com. Sustained winds could reach 35 mph, while peak gusts may reach 55 mph in some locations. Phoenix and surrounding communities are forecast to experience gusts of approximately 30 to 45 mph, according to FOX 10 Phoenix.

The strongest winds could also contribute to blowing dust and reduced visibility. The Storm Prediction Center has placed parts of central, southern and western Arizona under a marginal risk for severe thunderstorms, with damaging gusts the primary concern. An isolated tornado cannot be ruled out if atmospheric conditions become favorable, azcentral.com reported.

Temperatures will fall sharply after an unusually hot end to the workweek. Phoenix reached 104 degrees on Friday, October 9, compared with a typical high of 92 degrees, according to FOX 10 Phoenix. Saturday's high is forecast to drop into the lower 90s, followed by temperatures in the lower to mid-80s on Sunday and Monday.

By Tuesday and Wednesday, October 13–14, highs could fall into the upper 70s before gradually returning toward seasonal levels near 90 degrees. Overnight lows are expected to remain in the 60s after Tuesday, according to the regional forecasts.

ABC15 has designated Saturday, Sunday and Monday as Weather Action Days because of the anticipated combination of rain, thunderstorms and strong winds. Although Rachel's remnants are expected to move out of Arizona after the weekend, scattered precipitation could continue into Tuesday as a separate weather system affects the state.