Flood watch in effect as widespread rain soaks Southern Arizona through Monday morning

Residents across Tucson and Southern Arizona should be prepared for flooded roads, quickly rising water in washes and difficult driving conditions through early Monday morning, with a flood watch covering the entire region until 5 a.m. The storm has brought widespread rain and a few thunderstorms, and although the heaviest precipitation has shifted east, additional showers remain possible Sunday night and Monday morning. Low water crossings, drainage areas and roads that typically collect runoff could become hazardous with little warning.

The National Weather Service’s flood watch means the atmosphere and ground conditions are favorable for flooding, especially in low lying places, washes and areas with poor drainage. An earlier flash flood warning covered northeastern Pima County and south central Pinal County on Sunday. Even after the most intense rainfall moves away, lingering showers can add water to already saturated or runoff prone areas. People living near washes or traveling through rural parts of the region should continue monitoring conditions until the watch expires.

Drivers should not attempt to cross a flooded road or wash, even if the water appears shallow or the route is familiar. About a foot of moving water can sweep away most vehicles. Arizona’s “stupid motorist law” allows authorities to charge motorists for rescue costs when they drive around barricades into flooded areas and need help. Road users should also slow down, leave more space between vehicles and use extra caution during the first rainfall, when oil and other buildup on pavement can make roads especially slick.

The storm has affected communities beyond the Tucson area. In northern Arizona, Sedona officials issued mandatory “GO” evacuation orders for zones eight, nine and 10 as heavy rain and flash flooding moved along Oak Creek. Several highways were closed, and flooding also prompted evacuation orders and emergency declarations in Camp Verde. In the Phoenix area, the rainfall led to cancellations or postponements of major outdoor gatherings, including the annual Dia de los Muertos festival and events at the Arizona State Fair. Those impacts illustrate how quickly this system has disrupted travel and community activities across the state.

For Tucson, Monday is expected to begin cool and damp, with temperatures falling into the low to mid 50s across much of the metro area. Forecast lows include 55 degrees in Tucson and Marana, 54 in the Catalina Foothills and Sahuarita, and 53 in Oro Valley, Green Valley and Tanque Verde Falls. Catalina and Vail are expected to reach 52 degrees, while SaddleBrooke could drop to 51. Mount Lemmon is forecast to start the day at 42 degrees.

Showers should taper off Monday morning, but the day will remain cooler than usual. Tucson, Marana, the Catalina Foothills and Tanque Verde Falls are forecast to reach about 70 degrees, while Oro Valley and Sahuarita should top out near 69. Green Valley is expected to reach 68, Catalina and SaddleBrooke 65, Vail 64 and Mount Lemmon 46. Another forecast calls for Tucson to struggle into the upper 60s, with a high near 69 and a 30 percent chance of showers. Sunday night is expected to remain mostly cloudy, with a low around 56 and a 70 percent chance of precipitation.

Other parts of southeastern Arizona will also see cool conditions Monday. Morning lows are expected to range from the upper 40s to the mid 50s, including 48 degrees in Benson and Elfrida, 49 in Tombstone, 50 in Willcox and Sonoita, 51 in Douglas, 53 in Sierra Vista and Bisbee, and 54 in Bowie and Nogales. Afternoon highs should range from the mid 60s to near 70, with Douglas reaching 71, Bowie and Nogales near 70, Willcox and Elfrida at 68, Sierra Vista at 67, Tombstone at 66, and Bisbee and Sonoita at 65.

Once the remaining showers end, Southern Arizona is expected to settle into a drier pattern for the rest of the workweek. Sunshine should return, though temperatures are forecast to remain below normal through much of the seven day period. Overnight lows will generally stay in the low 50s, with Monday night near 49 and later nights mostly around 51 to 53. Afternoon temperatures are expected to warm into the mid 70s after Monday, reaching about 76 Thursday and 75 Friday, while mostly sunny or partly cloudy skies continue.