Heavy rain from thunderstorms resulted in major flash flooding in Spring Valley.
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The episode as NWS FGZ wrote it up.
Heavy rain from thunderstorms resulted in major flash flooding in Spring Valley.
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 20, 1:58 PM MST, 1 hour 2 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 158 PM MST Sat Aug 20 2022 .SYNOPSIS...An active monsoon pattern will continue across northern and central Arizona through Sunday. Heavy rainfall leading to flash flooding will continue to remain a threat. A slight downturn in storm activity is forecast early next week, especially north of the Mogollon Rim. Cooler temperatures are expected through the weekend before warming up next week. && .DISCUSSION...It has been a slow start to thunderstorm activity across our CWA today, but we are beginning to see some storms fire up across northwestern Coconino County and near the White Mountains. Although our 12Z sounding this morning came in lower than what has been seen previously this week, there is still good amounts of moisture in our atmosphere to tap into for the rest of the afternoon/evening hours. Sunday...We'll begin to see the northeasterly flow aloft move in from the high pressure system positioning to our northwest. This wind pattern will shuffle in drier air to the north/northeast portion of our state, limiting the potential for thunderstorm development in these areas. Areas along the Mogollon Rim and south are still forecast to see isolated to scattered showers for the afternoon and evening hours. Monday onward...Storm chances through mid-week will mostly remain for areas along I-40 and south as we continue to have drier air for the north/northeastern portion of our CWA. Around Thursday, model guidance is showing the high pressure system shifting back toward the Four Corners region. If this movement holds true, we could see additional active monsoon days toward the end of next week. && .AVIATION...For the 00Z TAF package...Scattered to numerous TSRA and SHRA through 02Z along and south of KCMR-KSEZ-KSOW-KJTC line with isolated TSRA elsewhere. Some areas will see showers and storms through the evening hours. Light winds away from storms through tomorrow. Similar conditions are expected Sunday with the most active areas being over higher terrain. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered showers and thunderstorms Sunday, primarily along and south of the Mogollon Rim with slightly reduced rain chances by Monday. Light winds except near storms. Localized flash flooding will be possible both days. Tuesday through Thursday...Rain chances remain each day with peak activity in the afternoons. Light winds will persist away from storms. && .FGZ WATCHES/WARNINGS/ADVISORIES... Flood Watch until 11 PM MST this evening for AZZ008-011-013>018- 037-038-108-111-113>118-137-138. && PUBLIC...Swenson AVIATION...JM FIRE WEATHER...JM For Northern Arizona weather information visit weather.gov/flagstaff
The Flagstaff radar (KFSX), 86 km away, was scanning. The volume nearest the first event began at 22:00 UTC.
1 flash flood. Local standard time, as filed.
Heavy rain from thunderstorms caused major flash flooding of roads and homes in Spring Valley on Hackberry Creek. Flash flooding in Mayer caused threatened the town water supply infrastructure.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2022Every state in 2022This day in weather historyWarnings in Arizona, August 2022
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: 1040732.