A retrograding upper level low combined with anomalously high moisture levels led to showers and isolated thunderstorms producing heavy rainfall and numerous instances of considerable flash flooding across south-central Arizona on the 25th. The places that saw the heaviest rainfall amounts were areas that experienced heavy showers training over the same locations.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PSR wrote it up.
A retrograding upper level low combined with anomalously high moisture levels led to showers and isolated thunderstorms producing heavy rainfall and numerous instances of considerable flash flooding across south-central Arizona on the 25th. The places that saw the heaviest rainfall amounts were areas that experienced heavy showers training over the same locations. Western portions of the Phoenix metro saw training showers with heavy rainfall occur, leading to widespread amounts of 1.5-2.5 with locally higher amounts of 3+. As a result, there were numerous reports of flash flooding, including multiple water rescues and numerous road closures due to flooding. Heavy rainfall also fell over multiple burn scars, leading to several instances of burn scar flash flooding. One of the burn scars that saw heavy rainfall was the Bush fire burn scar, which led to enhanced runoff and a rapid rise on Sycamore Creek. Several people were rescued after getting stuck in the increased flow in Sycamore Creek. No injuries were reported.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Phoenix, AZ wrote its last area forecast discussion before the first event at Jul 25, 5:03 AM MST, 3 hours 50 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 503 AM MST Sun Jul 25 2021 .UPDATE...Updated Aviation Discussion... && .SYNOPSIS... A low pressure system will continue to drift across Arizona into SE California early this week. With abundant moisture in place, showers and thunderstorms will be efficient rain producers capable of heavy amounts and localized flash flooding. However as the low pressure system lifts out of the region, much warmer and drier weather will temporarily return to the area during the middle of the week. Another wave of low pressure may affect the region during the end of the week bringing a return to more widespread shower and thunderstorm activity. && .DISCUSSION... The center of an upper low has moved into far eastern Arizona early this morning with numerous convectively enhanced vorticity centers spinning around the periphery of the entire larger circulation. Closest to the forecast area, the most notable MCVs are hovering over northern Pima County, as well as descending south from Yavapai County. Despite 00Z soundings showing decidedly moist adiabatic profiles, forced ascent and small perturbations associated with these features are tapping rich midlevel moisture and releasing the remaining minimal MUCape (200-500 J/kg). 00Z HREF members (particularly the WRF-ARW) have been capturing this evolution accurately, and agree on these 2 MCV features consolidating over SW Maricopa County early this morning. Fortunately, the unusually moist environment has tempered any available instability limiting convective potential. On the other hand, the unusually moist environment is creating highly efficient rainfall rates in otherwise pedestrian showers. Given this facet along with very wet antecedent soils, will continue with Flash Flood Watch today though impacts may be more muted and localized versus previous days. The aforementioned upper low will drift directly over south-central Arizona this afternoon into an environment that can only be characterized as anomalously moist (00Z soundings near daily maximums), yet highly overturned and convectively contaminated. Much like the past several days, cloud cover should inhibit surface insolation; however, persistent lift associated with the numerous vorticty centers acting on the very juicy midlevel moisture profiles will support scattered showers through much of central Arizona. Likely the stronger, more robust deep convection will be relegated to northern Arizona where a shortwave from southern Utah will become absorbed into the southern Arizona low, and aligned favorably into the 250mb right rear jet entrance region. CAMs are almost entirely in agreement showing a well defined convective system charging through Mohave County and potentially clipping La Paz and Riverside counties this evening. NBM POPs in a 60-70% range in these areas seem acceptable given the setup. During the first part of the week, the upper low will migrate from southern Arizona into the Los Angeles basin while the subtropical ridge strengthens and expands into the central plains. This evolution should bring a more subsident regime into the forecast area as well as reintroducing a warmer elevated mixed layer on top of the moist boundary layer. Seemingly, enough moisture and lift are forecast to linger in the western CWA by the NBM to keep 50% or greater POPs, though HREF members show very little activity throughout the entire CWA Monday afternoon. Though low level moisture will not be eliminated, there should be a modest reduction Tues/Wed such that any showers/storms would be relegated to higher terrain areas. And even these mountainous areas north and east of Phoenix may have limited action given the more unfavorable flow pattern. Nevertheless with the drying trend, temperatures will rebound much closer to normal during the middle of the week. Although difficult to assess smaller scale details among global ensembles, there does appear to be very good agreement in bringing another well defined closed easterly wave from the western Gulf of Mexico up to Rio Grande valley into south-central AZ late this week. While not quite as anomalous as the current weather system, there are indications this next feature may be somewhat more dynamic than the typical monsoon easterly wave in so much as the depth and jet energy associated with the PV center. Certainly, moisture availability should not be an issue and likely only minor timing and placement issues will determine the eventual details as NBM POPs are spread over an extended time frame owing to these uncertainties. && .AVIATION...Updated at 1200Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Weather will continue to bring aviation impacts for at least the next few hours. Main concerns will be moderate showers, lower cigs, and temporary reduction in visibility. Scattered showers across the Phoenix metro are likely to persist through at least sunrise, but confidence on timing is low. Any showers impacting the terminals may temporarily drop CIGs to 3K feet and visibilities as low as 2-3 miles. Anticipating a likely break in the showers later this morning before another round of shower activity this afternoon. Unfortunately, confidence in any specific forecast details is somewhat low. Showers should come to an end by this evening with CIGs rising to around 8-12K feet. Southeast California/Southwest Arizona including KIPL and KBLH: A disturbance moving through the region may bring isolated showers and thunderstorms across southeast California and southwest Arizona through early evening. Confidence in timing is fairly low, but best chance for showers and possibly a thunderstorm impacting terminals is during the afternoon. CIGs should remain VFR through the period. && .FIRE WEATHER... Tuesday through Saturday: Much drier conditions with temperatures closer normal will be common during the middle of the week with a potential return to stormy, wet weather by the weekend. While thunderstorms will be absent from most areas during the middle of the week, a few storms could impact far eastern districts though wetting rains may be very isolated. By the weekend, storm chances in eastern districts increase better than 50% with a returning threat of heavy rainfall. Otherwise, minimum afternoon humidity values will range from 15-35% during the middle of the week and closer to 25-50% into the weekend. Overnight recovery will be mostly good to excellent in a 40-80% range. Apart from thunderstorms, winds will favor typical daily upslope/drainage patterns. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Flash Flood Watch through this evening for AZZ534-537>563. CA...None. && DISCUSSION...18 AVIATION...Kuhlman FIRE WEATHER...18
The Phoenix radar (KIWA), 59 km away, was scanning. The volume nearest the first event began at 15:50 UTC.
22 flash flood, 1 flood. Local standard time, as filed.
A trained weather spotter reported multiple running washes with 6-12 inches of running water over Warren Road in multiple locations.
A trained weather spotter reported 4-6 inches of running water over the road near Legacy Park Boulevard and Mauna Loa Lane. No damage or injuries were reported.
Local media reported that heavy rainfall led to a home being flooded near 7th Street and Carefree Highway. Water was reported to having rose 5 feet into the home causing significant flood damage. The homeowner, who also runs a personal fitness gym at the home, reported that the gym equipment was destroyed in the flooding. The location was approximated as the exact location of the home is unknown. No injuries were reported.
The Maricopa County Flood Control District's Sonoran Wash streamflow gage exceeded bank full after peaking at 5.72 feet. Downstream impacts about one mile from the streamflow gage include unbridged crossings along North Valley Parkway and Dixileta Drive. No damage or injuries were reported.
A photo shows a vehicle became stranded in two to three feet of water near the intersection of Dell Webb Boulevard and Bell Road. Timing estimated from radar and other nearby reports. No injuries were reported and extent of water damage to the vehicle is unknown.
Multiple water rescues were reported in Sun City, including 98th Avenue and Granada Drive as well as 99th Avenue and Burns Drive. A flood control channel along the center of 99th Avenue was also reported to be overflowing onto the street. As a result, a Maricopa County Sheriff's Office deputy stopped southbound traffic at Desert Rock Drive due to the depth of the water. No injuries were reported.
A water rescue was reported at 107th Avenue and Mountain View Road. No injuries were reported.
The Arizona Department of Transportation reported that Highway 238 was closed between MP 14 and 38, which runs through both Maricopa and Pinal Counties, due to flooding. No damage or injuries were reported.
Several lanes on I-10 near 75th Avenue and 91st Avenue were flooded and became impassable. The I-10 westbound off-ramp at 59th Avenue was closed due to flooding. No damage or injuries were reported.
Emergency management reported multiple road closures in Buckeye due to flooding. Roads that were closed after experiencing flooding include Dean Road and Broadway Road, Lower Buckeye Road between Watson Road and Rainbow Road, Verrado Way and Broadway Road, and Verrado Way and Yuma Road. No damage or injuries were reported.
A video on social media showed several feet of standing water in the parking lot of an apartment, flooding numerous cars at the apartment. No injuries were reported.
Social media video from local media showed three vehicles stuck in the flooded intersection at 107th Avenue and Union Hills Drive. No injuries were reported.
County Public Works reported Price Road east of SR 79 in the Florence area was closed due to flooding. No injuries were reported.
A social media post showed knee deep water covering the road near Skyline Drive and Felix Road. No damage or injuries were reported.
A trained weather spotter reported that Bloody Tanks Wash was running near bankfull and containing debris. Water levels were reported to still be on the rise. The high flow in the wash was the result of heavy rainfall over the recent Telegraph fire burn scar, leading to enhanced runoff. No damage or injuries were reported.
Heavy rainfall over the recent Telegraph fire burn scar led to enhanced runoff into Pinal Creek. Video from a trained weather spotter showed significant flow through Pinal Creek impacting the unbridged crossing at Beer Tree Crossing and Jesse Hayes Road in Globe. No damage or injuries were reported.
A Maricopa County Flood Control District streamflow gage at Waterman Wash exceeded alarm stage, peaking at 4.66 feet and impacting downstream unbridged crossings along Tuthill Road and Narramore Road. Roads in this area along the wash were closed with social media videos showing swift moving water impacting these roads. No damage or injuries were reported.
The Sycamore Creek USGS gage (SYCA3) near Fort McDowell recorded a rapid rise with a 6 foot rise in 1.5 hours, cresting at 6.4 feet. This rapid rise is attributed to heavy rain that fell over the Bush fire burn scar, leading to enhanced runoff.
Tonopah-Salome Highway between 315th Avenue and 339th Avenue was closed due to flooding. This part of the highway is unbridged and crosses through the Hassayampa River. Timing estimated from a Maricopa County Flood Control District streamflow gage along the Hassayampa River. No damage or injuries were reported.
Several videos shared by broadcast media and social media showed instances of multiple vehicles getting stuck and/or swept away with multiple people having to be rescued in flash flood waters in Lower Sycamore Creek between the Verde River and Forest Service Road 403. Videos showed an SUV overturning in the creek with two men and an eight-year-old boy still inside. They were able to escape the vehicle with bystanders helping to pull them to safety on land. No injuries or fatalities were reported.
A video on social media showed a tractor trailer attempting to cross a flooded part of Highway 95 at MP 61. As the tractor trailer drove through the flowing flood waters, it quickly tipped over onto its side. According to the Arizona Department of Transportation, Highway 95 ended up closing due to the flooding. No injuries were reported.
The Arizona Department of Transportation reported water, mud, rocks, and debris flowing onto Riverside Drive in Parker, impeding travel. No damage or injuries were reported.
Video on social media showed Coolidge Fire Department performing a water rescue after a vehicle became stranded while attempting to cross the Gila River along Christensen Road. The increase in flow in the Gila River was a result of morning heavy rain that fell in the area hours before the water rescue. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, July 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 976258, 976260, 977458, 976459, 992752, 976483, 976510, 976259, 976513, 976261, 977457, 976514, 976265, 976266, 976647, 976522, 976566, 976596, 976590, 976631, 976646, 976642, 976267.