Deep monsoon moisture remained over northern Arizona which lead to thunderstorms with heavy rain and strong winds.
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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.
Deep monsoon moisture remained over northern Arizona which lead to thunderstorms with heavy rain and strong winds.
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 Jul 22, 9:07 AM MST, 2 hours 23 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 907 AM MST Sat Jul 22 2017 .SYNOPSIS...Active monsoon conditions will continue for the next several days. Heavy rainfall capable of producing flash flooding remains possible from stronger storms. && .UPDATE... Satellite imagery showing mostly clear skies across western Arizona, with mostly cloudy conditions across the Navajo nation. The amount of precipitable water in this mornings Bellemont sounding is slightly above normal. So it looks like an active thunderstorm day across northern AZ, with storms firing first along the Mogollon rim. The U of AZ WRF does suggest additional storm activity late this afternoon and evening across the northeast quarter of Arizona. && .PREV DISCUSSION /320 AM MST/...Monsoon moisture will remain in place across northern Arizona through Monday with the active weather pattern continuing. By Tuesday or Wednesday models show a bit drier and more stable air mass moving across the area with storm activity becoming more isolated except near the Arizona/New Mexico border. For today and Sunday...High pressure aloft was in the process of becoming centered over the Nevada/Utah border during this morning. The air mass remains moist across northern Arizona so look for another round of scattered to numerous showers and thunderstorms today. The position of the high will result in a steering flow that will nudge storms southward off the Mogollon Rim. The result will be a more focused area of shower and storm activity across a broad area containing Prescott and Payson. Stronger storms will be capable of producing 1 to 3 inches of rainfall. On Sunday, the high will wobble across utah with the flow becoming more easterly. This will probably mean drier air for the northeast corner of the state and a downturn in activity. However, from the Mogollon Rim south, the very active weather pattern will continue with some suggestion by model soundings of a more unstable environment with an enhanced threat for severe storms and flash flooding across the region south of the Mogollon Rim. On Monday...An upper disturbance will swing across northern Arizona. Not much upward motion or low-level flow for orographic forcing with this feature. Looking at model soundings the air mass will be near saturated through a deep layer. The result will likely be a good chance of showers, but without decent forcing for upward motion or sunshine to build instability, more showery than anything else. At least that's the way it looks at this point. Stay tuned. From Tuesday onward...Models show a drier low-level air mass moving in from over the eastern Pacific Ocean. Also, a building high pressure center aloft over Arizona may result in warming mid- level temperatures. All-in-all it appears that there will be a decrease in overall activity to mainly isolated except along the Arizona/New Mexico border. && .AVIATION...For the 18Z package...For the 18Z package...Sct to numrs shra/tsra and isold +tsra developing by 17z-19z. Highest coverage along/south of KFLG-KSJN line, with a secondary area west of KRQE. Coverage gradually decreasing aft 00z-02z. Expect MVFR/IFR conditions in the stronger storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Active monsoon conditions will continue through the weekend with scattered to numerous showers and thunderstorms. The best thunderstorm chances will be from the Mogollon Rim southward. Heavy rain and gusty winds will remain the primary impact. Expect near average temperatures across the area. Monday through Wednesday...Active monsoon conditions continue Monday with high rain chances. A slight downturn in storm chances is possible by Tuesday and especially Wednesday as a bit drier air moves in. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...DL/McCollum AVIATION...Peterson FIRE WEATHER...JJ For Northern Arizona weather information visit weather.gov/flagstaff
Hazardous Weather Outlook National Weather Service Flagstaff AZ 321 AM MST Sat Jul 22 2017 AZZ004>018-037>040-230315- Kaibab Plateau-Marble and Glen Canyons-Grand Canyon Country- Coconino Plateau-Yavapai County Mountains- Northeast Plateaus and Mesas Hwy 264 Northward-Chinle Valley- Chuska Mountains and Defiance Plateau- Little Colorado River Valley in Coconino County- Little Colorado River Valley in Navajo County- Little Colorado River Valley in Apache County- Western Mogollon Rim-Eastern Mogollon Rim-White Mountains- Northern Gila County-Yavapai County Valleys and Basins- Oak Creek and Sycamore Canyons-Black Mesa Area- Northeast Plateaus and Mesas South of Hwy 264- 321 AM MST Sat Jul 22 2017 This hazardous weather outlook is for Apache...Coconino... Northern Gila...Navajo...and Yavapai Counties in Northern Arizona. .DAY ONE...Today and Tonight Look for another round of scattered to numerous showers and thunderstorms. The steering flow aloft will be weak so storms today will be slow moving and capable of dropping 1 to 3 inch downpours. As a result, flash flooding will be possible with stronger storms. .DAYS TWO THROUGH SEVEN...Sunday through Friday Daily thunderstorms will continue into the middle of next week with the usual day-to-day variations of coverage and intensity. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
The Flagstaff radar (KFSX), 133 km away, was scanning. The volume nearest the first event began at 18:32 UTC.
2 flash flood, 1 heavy rain, 1 thunderstorm wind. Local standard time, as filed.
A thunderstorm produced 1.67 inches of rain in one hour just north of McNary.
Heavy rain over the Cedar Fire scar produced flash flooding in Carrizo Creek. The river gauge at Carrizo peak rose to 10 feet (215 PM MST). The creek was back down to 5 feet by 330 PM MST.
Heavy rain over the Cedar Fire scar caused flash flooding in Cedar Creek. The gauge at Highway 73 peaked at 6 feet and was receding at 300 PM MST.
A wet microburst produced high winds at the Prescott Airport (Love Field). The peak wind gust was 68 MPH at 325 PM MST. A few aircraft were moved/turned by the wind. No damage was reported. Strong winds were observed for 30 minutes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2017Every state in 2017This day in weather historyWarnings in Arizona, July 2017
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: 718733, 718724, 718728, 718732.