Phoenix weather turned dangerous Sunday evening as a line of severe thunderstorms swept through the metro area. The National Weather Service issued a severe thunderstorm warning for Phoenix, Glendale and Peoria. Wind gusts were forecast to reach as high as 80 mph, according to AZFamily. A wall of dust was also spotted just south of Interstate 8 in southern Maricopa County. That raised the possibility that blowing dust could push into the Phoenix metro area as the storms moved through.
The severe weather capped off a scorching stretch for the Valley. Phoenix hit a high of 111 degrees Sunday afternoon, according to AZFamily. That followed a blistering 113-degree high on Saturday, as reported by FOX 10 Phoenix. An Extreme Heat Warning that had been in place for the region expired at 8 p.m. Sunday. That offered a small measure of relief even as the new storm system arrived. Overnight lows over the weekend stayed in the 80s, FOX 10 Phoenix reported. That did little to ease the strain of a summer that has kept much of central and western Arizona above 110 degrees for days.
FOX 10 Phoenix reported that persistent high pressure had been driving the extended heat wave. Rising humidity typical of monsoon season made things worse. That same humidity also fueled dust and a lack of rainfall. Air quality pushed into the unhealthy-for-sensitive-groups range at times over the weekend, the station said. Showers and thunderstorms had already been crossing Arizona's high terrain throughout Saturday and Sunday afternoons and evenings. That activity set the stage for the more widespread storms that reached the Valley floor Sunday night.
Both AZFamily and FOX 10 Phoenix pointed to a building chance of Valley rain as the weekend progressed. FOX 10 Phoenix noted that the probability of storms in Phoenix climbed from 20% to 30% by Sunday. AZFamily reported outflow winds and areas of blowing dust were likely to spread into parts of the Valley overnight. There was also a slight chance of a shower or thunderstorm directly over the city.
A Cooling Trend Through the Week
Relief from the extreme heat is expected to build gradually as the week unfolds, both outlets reported. That relief will come with a continued chance of unsettled weather. AZFamily's forecast calls for a high near 108 degrees Monday. There is a 30% chance of scattered showers and thunderstorms developing Monday night into early Tuesday morning. FOX 10 Phoenix largely agreed. The station described Monday as starting dry and partly cloudy before turning sunnier in the afternoon. Scattered storms and blowing dust are possible again Monday evening into the night, potentially continuing into early Tuesday.
Tuesday is expected to bring a further step down in temperatures. AZFamily forecast an afternoon high around 104 degrees and a 20% chance of showers and thunderstorms extending into Wednesday morning. FOX 10 Phoenix similarly projected a high of 108 degrees for the day. The station framed the cooldown as dependent on how active Monday night's storms turn out to be. A very active night could mean a quieter Tuesday in the Valley before rain chances climb again midweek.
By Wednesday, AZFamily forecasts a high of just 101 degrees. The atmosphere is expected to stay unsettled, with a 30% chance of evening showers and thunderstorms. FOX 10 Phoenix's outlook is in line with that trend. The station projected that Valley temperatures could dip into the upper 90s to low 100s by Wednesday and Thursday. That cooldown comes as the high-pressure dome responsible for the recent heat wave shifts away from Arizona. AZFamily forecasts Thursday's high at around 100 degrees, with only a slight chance of an afternoon or evening shower.
The workweek is expected to close out on milder footing by Phoenix's summer standards. AZFamily projected a high near 103 degrees Friday. Temperatures are then expected to climb back into the 106-to-108-degree range next weekend, according to the outlet. That suggests the cooldown may be temporary rather than a lasting shift out of the region's typical late-summer heat pattern. Even with cooler numbers ahead, Phoenix weather is expected to stay active through the week.
Flooding and Storm Risks Across the Region
While the Valley braces for scattered storm chances, southern Arizona faces a more immediate flooding concern. AZFamily reported that a Flood Watch is in effect from Monday afternoon through Monday evening for southern Arizona, including Tucson. Across the high country of northern and eastern Arizona, isolated showers and thunderstorms were expected to continue through Sunday evening. More widespread storm activity was forecast from Monday through Thursday, the outlet said.
FOX 10 Phoenix cautioned that, as with most monsoon storms, the potential exists for strong winds, frequent lightning and heavy rainfall. That combination is capable of triggering flash flooding, a hazard familiar to longtime Valley residents. The station noted that storms during Arizona's monsoon season can develop and dissipate quickly. They can catch drivers and outdoor workers off guard with sudden dust, wind and downpours.
With heat and storm risks now overlapping, safety guidance from local agencies has taken on added weight. The Scottsdale Fire Department outlined the progression of heat-related illness. It starts with heat cramps marked by profuse sweating and muscle cramping. It can advance to heat exhaustion involving headache, dizziness and nausea. In its most severe form, heat stroke can bring a body temperature above 103 degrees, confusion, seizures or unconsciousness. The department recommended moving affected individuals to shade and cooling them with wet cloths at the neck, groin, armpits and head. It also advised offering sips of water only if the person is alert and not vomiting, and calling 911 immediately if symptoms worsen.
The Arizona Department of Health Services urged residents to stay in air-conditioned buildings and seek out cooling centers or hydration stations. It also recommended limiting outdoor activity during midday hours and checking on at-risk friends, family and neighbors at least twice daily. The agency also advised checking the UV index and local heat risk maps before heading outside.
As storms move in, the American Red Cross reiterated its long-standing flood safety message to turn around rather than drive through a flooded roadway. It also urged people to seek higher ground quickly if floodwaters rise around a stalled vehicle. The organization recommended keeping a battery-powered or hand-crank radio on hand and monitoring NOAA weather radio or local news for updates. It also suggested identifying a safe, window-free space at home to shelter during severe thunderstorms. As Phoenix weather shifts between extreme heat and monsoon storms this week, officials say staying informed remains the best defense.
