Deep monsoon moisture brought strong thunderstorms over parts of northern Arizona.
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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 brought strong thunderstorms over parts of northern Arizona.
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 17, 3:45 AM MST, 52 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 345 AM MST Mon Jul 17 2017 .SYNOPSIS...Expect numerous showers and thunderstorms along and south of the Mogollon Rim and White Mountains heading into Monday, with isolated storms elsewhere. Heavy rainfall rates from the stronger storms will be capable of producing flash flooding across parts of the area. Moisture is expected to increase by Tuesday and Wednesday, with shower and thunderstorm coverage increasing across northern Arizona. && .DISCUSSION... Another active weather day associated with the North American Monsoon is already underway as radar and satellite continue to show a mesoscale convective vortex currently drifting west south west over North Central Maricopa County. This byproduct from yesterday evenings storms will continue to drift across the state in the early morning hours, creating a cloud shield that could limit convection in late morning and early afternoon hours over parts of Yavapai and Northern Gila county if it takes its time exiting the area. A flash flood watch remains in effect through this evening due to an increased potential for flash flooding from the Mogollon Rim south into Northern Gila and Yavapai Counties. Across the higher terrain showers are once again expected to develop and move to the southwest as the the upper level ridge axis continues to remain over the eastern edge of the Great Basin. As this axis transitions towards the Four Corners by Tuesday night and Wednesday morning storms should begin to drift towards the Northwest from the Southeast...spreading the moisture and subsequent heavier precipitation type storms further across the Colorado Plateau. By Thursday, some models are beginning to show a decrease in afternoon convection coverage, due to a decrease in moisture. This decrease if it does occur does not currently look like a break in the monsoonal pattern, just a slight decrease in coverage in storms during this time frame. By the weekend another moisture looks to surge into the region with the higher moisture levels concentrating along the Arizona/New Mexico border. This would lead to an increase in flash flood potential for the White Mountains and Eastern Mogollon Rim if the pattern holds. && .AVIATION... For the 12Z package...VFR conditions will across northern Az through 17z though isolated -shra will continue. Btwn 17z-03z scattered to numerous thunderstorms will develop across the area, with a few storms becoming severe with 50 kt surface winds and hail up to an inch in diameter. Severe storms are most likely southwest of a KSEZ to KPRC line. Aft 03z Tues, convective activity decreasing but not ending. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Numerous showers and storms are expected along and south of the Mogollon Rim through Tuesday with scattered coverage elsewhere. Timing of storm activity will generally be from late morning through mid evening. Max temperatures to remain near normal. Wednesday through Friday...Increasing monsoon moisture will bring greater storm coverage across all of northern Arizona. && .FGZ WATCHES/WARNINGS/ADVISORIES...Flash Flood Watch through this evening FOR AZZ008-015>018-037- 038. && PUBLIC...Suk AVIATION...DL FIRE WEATHER...DL For Northern Arizona weather information visit weather.gov/flagstaff
Hazardous Weather Outlook National Weather Service Flagstaff AZ 326 AM MST Mon Jul 17 2017 AZZ008-015>018-037-038-180400- Yavapai County Mountains-Western Mogollon Rim- Eastern Mogollon Rim-White Mountains-Northern Gila County- Yavapai County Valleys and Basins-Oak Creek and Sycamore Canyons- 326 AM MST Mon Jul 17 2017 This hazardous weather outlook is for the The White Mountains and Mogollon Rim southwest into Northern Gila and Yavapai Counties in Northern Arizona. .DAY ONE...Today and Tonight A flash flood watch remains in effect through 10 pm tonight. Thunderstorms will develop this afternoon and evening across the higher terrain of the Mogollon Rim before moving to the lower elevations of Yavapai and Northern Gila Counties. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Activity will spread further northward with each day for better coverage north of the Mogollon Rim by the mid-week. Models suggest a slight drying trend could be possible by later next week depending on the movement of the high pressure but it is still early to settle on that outcome. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. AZZ004>007-009>014-039-040-180400- Kaibab Plateau-Marble and Glen Canyons-Grand Canyon Country- Coconino Plateau-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-Black Mesa Area- Northeast Plateaus and Mesas South of Hwy 264- 326 AM MST Mon Jul 17 2017 This Hazardous Weather Outlook is for portions of north central Arizona and northeast Arizona north of the Mogollon Rim. .DAY ONE...Today and Tonight Scattered showers and thunderstorms will develop off the higher terrain this afternoon and evening before moving across the surrounding area. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Activity will spread further northward with each day for better coverage north of the Mogollon Rim by the mid-week. Models suggest a slight drying trend could be possible by later next week depending on the movement of the high pressure but it is still early to settle on that outcome. .SPOTTER INFORMATION STATEMENT... Spotter activation is no anticipated at this time.
The Flagstaff radar (KFSX), 76 km away, was scanning. The volume nearest the first event began at 11:38 UTC.
3 flash flood, 2 thunderstorm wind, 1 flood, 1 hail. Local standard time, as filed.
Arizona Department of Public Safety reported 6 inches of water across State Route 377 at milepost 12.8.
Golf ball sized (1 3/4 inch diameter) hail fell 5 miles north of Iron Springs Road on Williamson Valley Road.
Strong winds from a thunderstorm tore a 24 foot by 72 foot metal roof off a shed. It tore the (metal) sheets off like paper, split/broke the 2X6s (wood rafters). Winds estimated at 50 to 55 MPH.
Power lines and trees were blown down by thunderstorm winds in Bagdad.
Big Chino Wash rose 3 feet in a short time at Highway 89.
Russell Wash was flooding in Lake Montezuma.
A flash flood was reported in Walker Creek, a tributary into Wet Beaver Creek, at 845 PM. The water was estimated to be flowing 4-5 feet deep in a normally dry area. Radar showed that two inches of rain fell southeast of the area an hour to an hour and a half earlier.
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: 719013, 718200, 718216, 718211, 718208, 718209, 718222.