Strong thunderstorms moved southwestward from New Mexico into San Simon that lofted areas of blowing dust creating a dust storm. Additionally, the heavy rainfall from the thunderstorm activity damaged two roadways that were closed for an unknown duration of time.
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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 TWC wrote it up.
Strong thunderstorms moved southwestward from New Mexico into San Simon that lofted areas of blowing dust creating a dust storm. Additionally, the heavy rainfall from the thunderstorm activity damaged two roadways that were closed for an unknown duration of time.
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 Tucson, AZ wrote its last area forecast discussion before the first event at Aug 31, 2:02 PM MST, 45 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 202 PM MST Sun Aug 31 2025 .SYNOPSIS...Isolated to scattered thunderstorms are expected to develop this afternoon and evening, mainly south and east of Tucson. Thunderstorm outflows could move through Tucson this evening leading to the potential for isolated thunderstorms. Gusty thunderstorm winds may produce blowing dust at times. Shower and thunderstorm chances continue through the coming week with day to day variability. High temperatures will be near normal through mid- week, then become below normal the second half of the week. && .DISCUSSION...Isolated thunderstorms have formed over the Gila in New Mexico and southern Greenlee County. This thunderstorm activity will expand westward and southward this afternoon and evening. Hi-res models also show isolated to scattered storm coverage over Santa Cruz County and southern Cochise Counties. High pressure will be centered just to the north of the CWA putting most of the area under east to northeast flow aloft. This will set up an opportunity for a rim shot late this afternoon into the evening. The last few runs of the HRRR have shown storms moving off the rim pushing an outflow into Graham and Cochise Counties around 4-6 PM, potentially reaching Tucson by 7-9 PM, and then Sierra Vista 8-10 PM. The 31/18Z Tucson sounding isn't very conducive to thunderstorm development, but an outflow could produce enough mechanical lift for some thunderstorms this evening. Main threat with storms today will be gusty winds especially in the Gila River Valley and I-10 corridor in Cochise County. The HREF is highlighting this area for highest probabilities for strong winds today. The HREF has a 20-35 percent chance for winds 45 mph or greater within 25 miles of a point from Safford down to Wilcox and east to San Simon. Blowing dust will be possible as the outflows move through. Localized heavy rain could also be a threat but will be secondary to strong outflow winds. Monday storm chances expand westward as moisture moves into western Pima County. Areas east of Tucson will begin to dry out a little but will still see a 20-30 percent chance for thunderstorms. The NAM and the GFS bring an easterly wave through northern Sonora Monday afternoon which could enhance thunderstorm activity along the international border and western Pima County. Still some uncertainty with its exact north/south placement. HREF members show storms forming over the rim again along with south and west of Tucson. However on the rim winds will be easterly instead of northeasterly like today, which leads to storms moving into Pinal and Maricopa Counties rather than Graham and Cochise Counties. Main threats will again be strong outflow winds and localized heavy rainfall. Tuesday and Wednesday mid-level flow stays easterly to southerly keeping a steady stream of moisture in place west of Tucson with further drying east of Tucson. Both days storm chances (30-40 percent) will be greatest west and south of Tucson and in the White Mountains. Tucson will be on the eastern edge of storm chances and could see isolated activity each day. Thursday into Saturday storm chances increase area wide thanks to the potential influx of tropical moisture. The current NHC forecast has an 80 percent chance of tropical storm formation over the next 7 days off the west coast of Mexico and southern Baja. The main question is where the tropical system will go once it approaches Baja. The ECMWF keeps it further west a few hundred miles off the west coast of Baja and the GEFS keeps it closer to Baja, potentially bringing it across the Gulf of California into southern Sonora. Right now NBM PoPs Thursday into Saturday are 30-60 percent across the CWA. && .AVIATION...Valid through 02/00Z. Isolated to scattered thunderstorms thunderstorms this afternoon, mainly south and east of KTUS. Coverage more likely near KSAD- KDUG-KOLS late this afternoon and evening. Gusty outflow winds up to 40 kts possible with any thunderstorm. The HRRR is showing the potential for an outflow boundary starting near KSAD this afternoon moving southwestward and getting to KTUS around 01/04Z, which could bring TSRA. Confidence is low on the thunderstorm chances, but high on the outflow changing winds to easterly/northeasterly with gusts up to 30 kts between 01/04Z-01/07Z at KTUS. Outside of thunderstorms sfc winds will be northerly 8-12 kts this afternoon and early evening at KTUS, and easterly at terminals south and east of Tucson. KTUS will turn easterly once the outflow moves through around 01/04Z. Aviation discussion not updated for TAF Amendments. && .FIRE WEATHER...Moisture increases east of Tucson today and across southeastern Arizona Monday, with minimum relative humidity values above 20 percent becoming widespread Monday. Daily chances for thunderstorms through this week with this increase in moisture, with day to day variability. Gusty outflow winds possible with any thunderstorm. East to southeast winds of 12-17 mph develop Monday, potentially lingering through Tuesday. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 00:03 UTC.
2 flash flood, 1 dust storm. Local standard time, as filed.
Trained spotter reported a dust storm along I-10 in San Simon that reduced visibility to less than 0.25 miles.
Riley Rd in San Simon are closed due to flash flooding causing roadway damage for unknown duration of time. A nearby rain gauge reported 0.62 inches of rainfall in the area.
Carr Rd in San Simon are closed due to flash flooding causing roadway damage for unknown duration of time. A nearby rain gauge reported 0.62 inches of rainfall in the area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2025Every state in 2025This day in weather historyWarnings in Arizona, August 2025
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: 1291735, 1291733, 1291734.