Monsoon activity moved into parts of the Valley Saturday evening, bringing rain, strong gusts and pockets of reduced visibility as storm cells advanced westward from the higher terrain. Radar imagery from late afternoon showed multiple cells east of the Phoenix metro drifting toward the Valley; meteorologists noted the activity had begun and could continue into the evening, potentially lasting until about 8 p.m. The Phoenix area climbed to 117 degrees earlier in the day but did not record a new heat record before the storms arrived.
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NWS KIWA radar reflectivity showing monsoon storm cells east of the Phoenix metro — including activity near Queen Creek and Globe — moving toward the Valley.
National Weather Service updates issued throughout the afternoon described strong outflow boundaries and gusty conditions as the primary concerns for residents and recreational users. At about 3:40–3:41 p.m., the weather service reported that strong winds were surging into the lower elevations, with outflow boundaries visible as fine lines on radar reflectivity. Those statements warned of wind gusts in the 30 to 50 mph range across lower elevations, with locally stronger winds expected along the Salt River Valley. A brief advisory pointedly advised boaters to be aware of rapidly changing wind conditions on the water.
Shortly after those wind-focused posts, a special weather statement was issued for Phoenix, Mesa and Chandler — an alert that remained in effect until 4:45 p.m. MST, according to the timeline of updates. Forecasters continued to highlight the outflow-driven nature of the event; these boundaries pushed west and ahead of the main storm cores, producing sudden gusts, blowing dust and localized reductions in visibility as they propagated across the Valley floor.
By 5:36 p.m., meteorologists reported that an outflow boundary was still surging westward and that people should expect wind gusts generally around 35 to 45 mph along the leading edge. That same update noted the potential for blowing dust and low visibilities where the gusts were strongest. The 5:36 p.m. bulletin also indicated that the immediate threat for new showers and storms across the Phoenix metro area was diminishing at that time, even as the gusty outflow continued to affect surface conditions.
While portions of the Valley were coping with gusts and dust, a separate warning was posted for parts of Yavapai County. At 4:32 p.m., a flash flood warning was announced, remaining in effect until 7:30 p.m. MST. The warning explicitly listed affected locations, naming Castle Hot Springs, Castle Creek Boat Ramp, Coles Bay, Cottonwood Day Use Area, Humbug Bay and Goose Bay. The flash flood warning covered areas where heavy downpours from monsoon cells had the potential to produce rapid runoff and localized flooding.
Throughout the sequence of advisories and warnings, radar imagery remained a key tool for tracking the cells and outflow boundaries. Observers noted the fine-line signatures of outflow on reflectivity scans and the translation of storm activity from the higher terrain toward the Valley. Forecasters reiterated that gusts of 30–50 mph were expected in the lower elevations and cautioned that winds could be locally stronger in some corridors, particularly along the Salt River Valley. The combination of gusty winds, blowing dust and brief but intense rainfall created a rapidly changing afternoon into early evening for communities across the region.
By early evening, officials continued to monitor the situation as the monsoon line of storms moved through and across surrounding areas. The live radar loop available during the event showed the progression of cells and the evolving outflow structure that prompted the scattered advisories. With the flash flood warning covering parts of Yavapai County through 7:30 p.m. and monsoon activity possibly persisting until around 8 p.m., responders and the public tracked updates as conditions changed across the Valley and nearby counties.
Following the outflow boundary's passage, Phoenix Sky Harbor's official low for July 25 settled at 95°F, setting a new record for the warmest low temperature on that date, according to @NWSPhoenix. The storms provided some cooling from the day's near-117°F high but left overnight readings unusually warm.