A thunderstorms produced heavy rain over the Cataract/Havasu Creek Drainage that resulted in flash flooding.
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The episode as NWS FGZ wrote it up.
A thunderstorms produced heavy rain over the Cataract/Havasu Creek Drainage that resulted in flash flooding.
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 13, 3:58 PM MST, 1 hour 2 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 358 PM MST Sun Aug 13 2017 .SYNOPSIS...Expect scattered showers and thunderstorms this afternoon and evening, with flash flooding and lightning being the primary threats. Much drier air will bring a decreasing trend in storm coverage by Monday, with isolated or no storms from Tuesday through the remainder of the week. && .DISCUSSION...Scattered thunderstorms moved northeastward across northern Arizona this afternoon. Storms will decrease this evening. A strong trough of low pressure is moving across the Pacific Northwest this afternoon. This trough will move southeastward toward Arizona on Monday and increase southwest flow over the state. This will push monsoon moisture away from the area with a significant decrease in thunderstorm activity. Wind gusts in excess of 30 MPH are possible Monday afternoon on the Coconino and Kaibab Plateaus. The trough of low pressure will move across northern Arizona on Tuesday with breezy to windy conditions. Only isolated showers and thunderstorms will remain...at best. Seasonable temperatures and afternoon southwest breezes are expected after Wednesday. Moisture begins to slowly by late Friday and over next weekend with increasing chances of showers and thunderstorms. && .AVIATION...For the 00Z package...Scattered showers and thunderstorms will continue into the early evening with storms most concentrated along the Mogollon Rim and to the northeast. Localized MVFR/IFR conditions expected in the stronger storms. Storm coverage and intensity will diminish after 03Z Monday. Widely scattered thunderstorms may develop again after 18Z Monday. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A decreasing trend in storm coverage is expected beginning Monday, with only a slight chance for showers in the White Mountains by Tuesday. Breezy southwest winds are also expected for Monday and Tuesday afternoons. Wednesday through Friday...Dry conditions with generally light winds are anticipated. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...MAS AVIATION...KD FIRE WEATHER...KD For Northern Arizona weather information visit weather.gov/flagstaff
Hazardous Weather Outlook National Weather Service Flagstaff AZ 627 AM MST Sun Aug 13 2017 AZZ004>018-037>040-140200- 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- 627 AM MST Sun Aug 13 2017 This hazardous weather outlook is for Apache...Coconino... Northern Gila...Navajo...and Yavapai Counties in Northern Arizona. .DAY ONE...Today and Tonight Expect scattered showers and thunderstorms initiating around mid- day, with the greatest coverage anticipated from the Mogollon Rim and Coconino Plateau northeastward. Modest deep-layer wind shear will support some storm organization. Atmospheric moisture has decreased somewhat relative to yesterday, but west-northwest winds could cause multiple storms to develop over the same areas, yielding a flash flood threat. Thunderstorms today could produce some hail in addition to cloud-to-ground lightning. .DAYS TWO THROUGH SEVEN...Monday through Saturday Thunderstorm coverage will decrease on Monday, and wind speeds will increase in response to the approach of a trough from the Great Basin. Wind gusts in the 30-40 mph range are likely on Monday afternoon along the Coconino and Kaibab Plateaus. The trough will cross northern Arizona on Tuesday, bringing breezy conditions and significant drying to the region. A break from thunderstorms and precipitation is currently expected from Tuesday through at least Friday, and likely for most of the area through Saturday. Moisture is expected to gradually increase early next week. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
The Cedar City radar (KICX), 159 km away, was scanning. The volume nearest the first event began at 00:02 UTC.
1 flash flood. Local standard time, as filed.
A thunderstorm produced heavy rain and a flash flood that the Supai Police tracked as it moved down through Havasu Creek. The river gauge near the Village of Supai rose around 2 feet.
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: 720664.