An upper air disturbance moving eastward across northern Arizona and southern Utah|allowed showers and thunderstorms to continue over night across central |Arizona. Some storms reformed over the same area leading to flooding issues across Yavapai County.
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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.
An upper air disturbance moving eastward across northern Arizona and southern Utah|allowed showers and thunderstorms to continue over night across central |Arizona. Some storms reformed over the same area leading to flooding issues across Yavapai County.
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 Aug 4, 9:58 AM MST, 2 hours 4 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 958 AM MST Fri Aug 4 2017 .SYNOPSIS...Another round of showers and thunderstorms is expected today before a drier and more stable airmass moves into the region over the weekend into early next week. This will result in much less storm coverage across northern Arizona. && .DISCUSSION... Current forecast with another round of showers and thunderstorms today remains on track. Little updates to the forecast are anticipated this morning. && .PREV DISCUSSION /337 AM MST/... Drying conditions are expected to begin today as dry air is expected to move into the area from the southwest today and spread northeastward as the weekend develops. Showers and thunderstorms are still expected to be scattered to widespread this afternoon and evening, with the only potential decrease in activity over Yavapai County where the drier air is expected. As each day passes more drier air is expected to be advected into the region due to the parent low pressure system off the California coast. While the decreasing moisture will limit the amount of storms developing over the area, some isolated showers will still be possible through the afternoon hours this weekend. This drying trend looks to be short lived though, with model solutions continuing to show a return to wetter conditions by the later half of the work week due to an easterly wave making its way across the Texas and Mexico and into the Four Corners. Consistency between model forecast runs has raised confidence in this occurrence, however, the fact that this event would occur 6 to 7 days out does yield enough uncertainty to decrease chances of precipitation in the extreme long term. && .AVIATION...For the 18Z package...VFR conditions this morning with scattered -SHRA across northeastern Arizona. Expect scattered TSRA to develop across all of northern Arizona 17Z-02Z. Stronger storms will produce MFR to IFR conditions and typical gusty winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect scattered showers and thunderstorms today and Saturday with areas of moderate to locally heavy rain. Gusty winds will develop near any storms. Sunday through Tuesday...A drying trend is expected with only isolated showers and thunderstorms across far northern and eastern Arizona by Monday and Tuesday. Near average temperatures are expected. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...KD/Suk AVIATION...MCT FIRE WEATHER...MCT For Northern Arizona weather information visit weather.gov/flagstaff
Hazardous Weather Outlook National Weather Service Flagstaff AZ 240 AM MST Fri Aug 4 2017 AZZ004>018-037>040-050330- 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- 240 AM MST Fri Aug 4 2017 This hazardous weather outlook is for Apache...Coconino... Northern Gila...Navajo...and Yavapai Counties in Northern Arizona. .DAY ONE...Tonight The most likely initial development will be over the White Mountains and Mogollon Rim later this morning, with storm motion to the North and Northeast. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Moisture begins to decrease across the area limiting storms to a more isolated pattern through the weekend and into early next week. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
The Flagstaff radar (KFSX), 97 km away, was scanning. The volume nearest the first event began at 18:59 UTC.
4 flash flood, 1 heavy rain. Local standard time, as filed.
Heavy rain over the Goodwin Fire scar caused a flash flood in Big Bug Creek The river gauge at State Route 69 reported a peak of 5.1 feet...an estimated four foot rise.
The Sedona Fire Department could not respond to an emergency call due to water flowing over Verde Valley School Road. At least two feet of water was flowing over the road.
Beaver Creek Road was impassible due to flash flooding at School Hose Wash.
The stream gauge on Beaver Creek (2 SW McGuireville) showed a sudden rise of three feet.
An inch and a half of rain caused minor street flooding in the Sedona Shadows Neighborhood.
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, August 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: 720434, 720435, 720454, 720455, 720456.