Thunderstorms moved through the Tucson Metro area on the afternoon and evening of September 17th. Two storms moved through the metro, producing heavy rainfall and flash flooding.
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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.
Thunderstorms moved through the Tucson Metro area on the afternoon and evening of September 17th. Two storms moved through the metro, producing heavy rainfall and flash flooding. The winds from the storms caused a tree to fall on power lines causing a power outage Additionally, thunderstorms moved northward along Interstate 10 from Tucson to Eloy, AZ causing dust to be lofted and reduced visibilities to below 900 yards for a brief period 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 Sep 17, 2:39 PM MST, 3 hours 31 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Tucson AZ 239 PM MST Wed Sep 17 2025 .SYNOPSIS...Moisture has moved into the region which will lead to scattered showers and thunderstorms through the end of the work week with gradually diminishing thunderstorm chances over the weekend. Temperatures near to just below normal into the weekend before warmer and drier weather returns next week. && .KEY MESSAGES... - Isolated to widely scattered showers and thunderstorms this afternoon with heavy rainfall may result in localized instances of flash flooding, mainly west and south of Tucson. - Increasing chances (40-60%) for isolated showers and storms becoming scattered in the afternoon to early evening hours. Isolated instances of flash flooding possible. - Chances (30-60%) for showers and thunderstorms with heavy rain continue on Friday, but decrease over the weekend with high temperatures returning to near triple digits for the Tucson Metro by the start of next week. && .DISCUSSION...Isolated slow moving showers and storms have been developing first over the higher terrain areas across southeast Arizona mainly south and west of Tucson. Clouds have thinned enough for the atmosphere to destabilize, eroding away convective inhibition, especially to the south and west of Tucson. This is also where better moisture resides with precipitable water over 1.5". The KTWC 17/18Z sounding measured 1.4" of precipitable water continuing to support the solution that any storms that form today are in an environment that favors flash flooding rather than wind, especially west and south of Tucson. Tomorrow into tomorrow evening chances (30-60%) for scattered showers and thunderstorms will continue across southeast Arizona with above normal precipitable water in place from the now post tropical cyclone Mario located off the coast of Baja California. The potential for heavier rain will expand north and eastward as a modestly strong upper level jet aids synoptic scale support for ascent in addition to localized terrain forcing. Like today, storms will first tend to remain isolated firing off the higher terrain areas. However, anticipate storms to become more scattered in the mid to late afternoon and early evening hours and push off the mountains. The biggest limiting factor as of now continues to be residual cloud cover. Chances (30-60%) for scattered showers and storms continue again on Friday with a continued threat for localized heavy rainfall. Over the weekend, precipitation chances begin to decrease as the Monsoon high circulation nudges north putting southeast Arizona in a westerly flow pattern. Consequently, a gradual warming and drying trend is expected with high temperatures rebounding to near 100 degrees heading into next week for the Tucson Metro and points west. && .AVIATION...Valid through 19/00Z. BKN-OVC clouds 6k-10k ft AGL and BKN-OVC layer AOA 18k ft AGL thru the valid period. Scattered TSRA possible through 18/04Z. Best chances will be at KDUG and KOLS terminals. With showers and thunderstorms, expect locally heavy rainfall and erratic winds up to 35 kts. Other than thunderstorm driven winds, SFC winds will be from the south southwest 5-10 kts in the afternoon and evening becoming variable less than 7 kts at other times. Tomorrow, scattered TSRA possible again after 18/19Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Above normal moisture this week leading to min RH between 20-40 percent through the weekend. Expect scattered shower and thunderstorm chances (30-60 pct chance) each day through Friday, then diminished thunderstorm chances this weekend. Dry conditions return next week. 20-foot winds will be 8-12 mph with some afternoon/early evening gusts to around 20 mph over the next week with normal diurnal patterns through the weekend. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && DVS Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
The Tucson radar (KEMX), 49 km away, was scanning. The volume nearest the first event began at 01:11 UTC.
1 flash flood, 1 thunderstorm wind, 1 dust storm. Local standard time, as filed.
Video of water overtopping curbs west of university campus. An estimated 6 inches of water were on the roadway.
Thunderstorm winds caused a tree to fall on powerlines at the intersection of 5th Street and North Alvernon Way. This caused a power outage for an unknown number of customers and for an unknown duration of time.
Arizona Department of Transportation dust sensor reported visibility at roughly 900 yards at mile marker 213 on Interstate 10 near Eloy, AZ.
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, September 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: 1295405, 1295406, 1295407.