Strong to severe storms, flash flooding possible in southern Arizona today

Tucson residents should be prepared for another round of potentially strong to severe thunderstorms today, with heavy rain, flash flooding, powerful wind gusts and blowing dust possible across the region. A Flash Flood Watch remains in effect through tonight for the Tucson metro area, central and eastern Pima County, western Cochise County and all of Santa Cruz County. Storm activity was tracked north and east of Tucson earlier this morning, and forecasters expect scattered storms to develop again later in the day.

The immediate concern is not simply whether rain falls, but how quickly it arrives and where storms stall or move across already vulnerable areas. Downpours can overwhelm washes, low water crossings and drainage systems, while gusty outflow winds can spread dust well beyond the storm itself. The Tucson forecast calls for a 50 percent chance of showers and thunderstorms today, with partly sunny skies and a high near 98 degrees. The chance of storms rises to 60 percent tonight, when the low is expected to be around 73.

A Severe Thunderstorm Watch has also been issued for south central Arizona through midnight, with possible hazards including wind gusts up to 70 mph, hail around 1 inch in diameter, frequent lightning and localized heavy rainfall. Blowing dust and sharply reduced visibility are particular concerns in Pinal County, where outflow boundaries from storms in southern Arizona could push northward. Those boundaries may also collide over the Phoenix area, creating another opportunity for strong or severe storms there overnight.

The broader storm threat follows destructive weather in the Phoenix area Sunday night. Monday was quieter in Phoenix, although temperatures still reached 108 degrees, and showers and thunderstorms continued across the high country during the afternoon and evening. Forecasters said storms in southern Arizona and the high country could send dust and severe weather back into the Valley overnight, with scattered showers and thunderstorms continuing across Arizona. The system illustrates how storms far from Tucson can still affect travel and air quality through wind driven dust and shifting outflow boundaries.

Rain chances will continue into Monday in the Tucson area, when the forecast calls for a 60 percent chance of showers and thunderstorms, mostly sunny skies and a high near 92. Monday night brings a 40 percent storm chance and a low around 71. How active and severe Monday becomes will depend in large part on what happens today. Tuesday is expected to be mostly sunny with a high near 96, and the chance of thunderstorms drops to 10 percent Tuesday night. The week should remain relatively warm, with highs near 98 on Thursday and Friday, followed by a 40 percent storm chance Friday and 30 percent Saturday. Drier conditions are expected to return statewide over the weekend, although the Tucson forecast still lists a 20 percent storm chance Thursday.

People driving or walking around Tucson should avoid flooded roads and washes, even when water appears shallow. Emergency safety guidance warns that only 6 inches of moving water can knock a person off their feet, while 12 to 24 inches of fast moving water can carry away a vehicle. Another local safety reminder says less than 10 inches of flowing water can wash a car away. If water begins rising around a vehicle, drivers should leave it quickly and move to higher ground, but only if doing so is safe. Residents should never cross barricades or attempt to drive through moving water.

Lightning, hail, damaging winds and dust can create hazards even outside the heaviest rain. Anyone caught outdoors should seek shelter in a sturdy building or vehicle and stay away from windows, skylights and glass doors. A household should identify an interior safe place before storms arrive, ideally a room without windows, where people can gather if wind or hail intensifies. Residents in flood prone neighborhoods should be ready to evacuate quickly, follow official instructions and wait for authorities to say it is safe before returning.

Monsoon preparations are also important because storms can interrupt water, electricity and gas service. Fire officials recommend keeping flashlights and extra batteries available, storing food that does not require cooking or refrigeration, and having at least a gallon of clean water per person. Households that rely on powered medical equipment should arrange backup power, and residents should keep a charged backup option for cellphones and an accessible first aid kit. Downed power lines should never be approached, since the ground may remain energized as far as 200 feet away. If electricity goes out, use flashlights instead of candles or other open flames.

The heat remains a concern between storms, even with temperatures easing into the 90s during the coming workweek. People working or exercising outdoors should drink water before, during and after activity, limit strenuous time during the hottest part of the day, wear light and loose clothing, and avoid hiking alone. Heat exhaustion can involve headache, dizziness, weakness, nausea, cool or damp skin and heavy sweating. Confusion, a body temperature above 103 degrees, hot dry skin, rapid breathing, seizures or unconsciousness can signal heat stroke and require immediate emergency help. Residents should check on older adults, neighbors and others at risk at least twice daily, while staying alert for changing weather and updated warnings.