Moisture increasing from the south triggered severe thunderstorms across northern Arizona.
Every event with a place to put it. Tap one for its entry below.
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.
Moisture increasing from the south triggered severe thunderstorms across 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 11, 2:50 PM MST, 58 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 250 PM MST Sun Jul 11 2021 .SYNOPSIS...Hot weather continues today, with chances of afternoon and evening showers and thunderstorms, primarily south of the I-40 corridor. More significant moisture looks to return next week, with greater chances for showers and thunderstorms across much of northern and central Arizona. && .DISCUSSION...Most convective activity so far has been south of the I-40 corridor and west of the I-17 corridor. Convection was slow to start, but as a few stronger cells start to move into the higher PW airmass south of the rim, there is room to grow. The mid-levels of the sounding are quite unstable and we expect a few low-end severe cells as a result. Convection should die off or move south of our area this evening. Heading into next week, expect a very active pattern as the monsoon opens up full-throttle upon Arizona. Heat concerns will fade and flooding concerns will become the dominant impact. && .AVIATION...For the 00Z package...Mainly VFR conditions prevail for the duration of the TAF period. Sct SHRA/TSRA and ISOLD +TSRA along and south of a KGCN-KFLG-KJTC line through 03Z. Localized MVFR conditions with the stronger storms. Convective activity redevelops AFT 19Z Monday, with locations farther north and east being affected as compared to Sunday. Winds outside of convection remain generally light. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect increasingly active monsoon conditions Monday and Tuesday, with lowering temperatures and increased minimum relative humidity. Winds remaining light, except near storms. Wednesday through Friday...Expect an active pattern, with scattered to numerous showers and thunderstorms each day. As a result, expect cooler temperatures and generally light winds. && .FGZ WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST this evening for AZZ005-006. && PUBLIC...Peterson AVIATION...Peterson FIRE WEATHER...Peterson For Northern Arizona weather information visit weather.gov/flagstaff
Special Weather Statement National Weather Service Flagstaff AZ 322 PM MST Sun Jul 11 2021 AZZ008-112245- Yavapai County Mountains- 322 PM MST Sun Jul 11 2021 ...SIGNIFICANT WEATHER ADVISORY FOR A STRONG THUNDERSTORM IN YAVAPAI COUNTY UNTIL 345 PM MST... At 321 PM MST, Doppler radar was tracking a strong thunderstorm over Prescott Gateway Mall, or near Prescott Valley, moving north at 10 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Prescott Valley, Prescott, Downtown Prescott, Groom Creek Subdivision, Oak Knoll Village, Prescott Gateway Mall and Lynx Lake Dam. PRECAUTIONARY/PREPAREDNESS ACTIONS... Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 3448 11233 3447 11247 3456 11248 3456 11230 TIME...MOT...LOC 2221Z 180DEG 8KT 3453 11240 NL
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
343 PM MST SUN JUL 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0338 PM HAIL DEWEY-HUMBOLDT 34.53N 112.25W
07/11/2021 M0.89 INCH YAVAPAI AZ NWS EMPLOYEE
MIX OF DIME AND NICKEL SIZED HAIL.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
348 PM MST SUN JUL 11 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0348 PM HAIL 2 WSW DEWEY-HUMBOLDT 34.52N 112.29W
07/11/2021 E1.00 INCH YAVAPAI AZ PUBLIC
&&The Flagstaff radar (KFSX), 109 km away, was scanning. The volume nearest the first event began at 22:50 UTC.
1 hail, 1 thunderstorm wind, 1 tornado. Local standard time, as filed.
One inch to 1 1/4 inch hail was reported between Dewey-Humboldt and 4 miles south and south-southwest of Prescott by several people. Tree leaves were shredded off many trees.
The Prescott Airport ASOS reported a peak wind gust of 83 MPH. Four power poles were snapped off in Prescott Valley (police report). The wind gusts were estimated to be 60 MPH in Prescott Valley. Carport roof blown off structure and landed on the ground in Chino Valley. Roof damage to an apartment complex in Prescott.
A trained spotter observed a tornado west of Outer Loop Road and State Route 89 for 45 seconds. intermittent cloud to ground rotation was confirmed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyThe tornado archive for Arizona, 2021Warnings in Arizona, July 2021
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: 977484, 977485, 977487.