Monsoon thunderstorms became strong enough to produce some severe downburst winds in a couple locations.
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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 FGZ wrote it up.
Monsoon thunderstorms became strong enough to produce some severe downburst winds in a couple locations.
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 Flagstaff, AZ wrote its last area forecast discussion before the first event at Sep 10, 4:27 PM MST, 1 hour 16 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 427 PM MST Wed Sep 10 2025 .SYNOPSIS...Cooler and windier conditions are expected. Showers and thunderstorms will be possible through Friday, mainly across eastern Arizona. Dry conditions will then return by this weekend. && .DISCUSSION...Today...Strong, gusty winds have developed across northern Arizona this afternoon as a strong trough has begun to move into the Great Basin. Peak gusts upwards of 35-45 mph look probable this afternoon along and downwind of the higher terrain, with locally higher gusts in excess of 50 mph in the usually windy locations. Winds should largely subside overnight as the boundary layer decouples, however areas downwind of the terrain that remain mixed may see elevated gusts through the overnight hours. Moisture has begin to increase across portions of northern Arizona today as the increased southerly flows aids in advecting sub- tropical moisture northward. This moisture increase largely looks to be shallow based on the 18Z FGZ RAOB, especially west of I-17/US-89, thus likely limiting any development. To the east, satellite imagery already shows some convective initiation over the eastern Mogollon Rim and White Mountains where deeper moisture looks to reside. Latest guidance from the U of A WRF and HRRR do show a complex of storms developing across east-central Arizona and moving northward through this afternoon and evening, however this may be over done. Some weak shear (~30 kts) may allow for a few isolated strong storms over eastern Arizona later this afternoon. Thursday and Friday...Heights continue to fall as the trough axis draws closer. As this occurs, a narrow corridor of increased moisture advection looks to develop across the eastern-half of Arizona. As a result, a round of scattered showers and thunderstorms are expected to develop, mainly over Navajo and Apache counties by Thursday afternoon. Some activity may also linger into the overnight hours Thursday night. As the mean trough axis moves through Arizona, drier air increases from the west, thus keeping the western-half of the state largely rain free. While storms do look to remain on Friday, coverage looks to largely shift into Apache County with the increasingly drier air. With the added dynamics from the trough, there will be the potential for a few strong to severe thunderstorms capable of producing large hail and damaging winds on Thursday. Increased storm motions will limit the threat for flash flooding, however some localized flash flooding will still be possible where training storms occur. With the tight pressure gradient still in place, gusty winds look to remain on Thursday, especially along and north of the Mogollon Rim. An additional Wind Advisory may be needed for the Little Colorado River Valley on Thursday. Winds look to begin to weaken on Friday, but still remain breezy. Saturday through Tuesday...In the wake of the trough, cooler and drier air looks to set in across much of northern Arizona. As a result, dry conditions look to prevail through at least the weekend. Near the start of next week, a potential tropical system (EP95) may initiate a moisture surge northward up the Gulf of California. At the same time however, another trough looks to move into the Great Basin. This could help to pull the moisture into northern Arizona, but likely only over a short-lived period as it will eventually usher in drier air once again. Ensemble guidance still varies a bit with the exact timing and tack of the two system, thus, confidence in any exact details is low at this point. && .AVIATION...Thursday 11/00Z through Friday 12/00Z...Mainly VFR conditions expected. Isolated -SHRA/-TSRA possible over Eastern Mogollon Rim, White Mountains and Chuska Mountains between 18Z Thursday and 02Z Friday. Winds S-SW 5-15kts, gusts to 20kts overnight, increasing to S-SW 15-20kts, gusts to 35kts between 15Z-18Z Thursday. OUTLOOK...Friday 12/00Z through Sunday 14/00Z...Mainly VFR conditions expected. Isolated -SHRA/-TSRA possible over Eastern Mogollon Rim, White Mountains and Chuska Mountains between 18Z-02Z each day. Winds SW 15-20kts, gusts to 35kts Friday, SW-W 10-15kts Saturday during the daytime. S-SW 5-10kts overnight Friday, light and variable or terrain driven overnight Saturday. && .FIRE WEATHER...Thursday and Friday...Slightly cooler and windy both days. Expect southwest winds from 15 to 25 mph, with gusts from 35 to 45 mph each day, from late morning through early evening. Some moisture being pulled into eastern Arizona will also allow for daily showers and thunderstorms, some some storms could be strong. Storms will largely be confined to Apache and Navajo counties. Saturday through Monday...Daytime temperatures a few degrees below normal. Conditions will rapidly dry from west to east, with minimum relative humidity values mainly in the teens through the period. Expect daytime south through southwest winds 10 to 20 mph. && .FGZ WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 7 PM MST /8 PM MDT/ this evening for AZZ004- 006>009-012-013-015-016-039-040. && PUBLIC...Humphreys AVIATION...Bernhart FIRE WEATHER...Peterson For Northern Arizona weather information visit weather.gov/flagstaff
The Flagstaff radar (KFSX), 101 km away, was scanning. The volume nearest the first event began at 00:42 UTC.
2 thunderstorm wind. Local standard time, as filed.
The ADOT site located on SR-77 at 14 mile hill (AZT12) measured a 60 mph thunderstorm wind gust.
The St. Johns Airport ASOS station (KSJN) measured a 64 mph thunderstorm wind gust.
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: 1289001, 1289003.