Abundant moisture over northern Arizona allowed strong thunderstorms with heavy rain and rotation to form across the area.
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.
Abundant moisture over northern Arizona allowed strong thunderstorms with heavy rain and rotation to form across the area.
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 30, 3:24 PM MST, 22 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 324 PM MST Fri Jul 30 2021 .SYNOPSIS...Abundant monsoonal moisture will persist over northern Arizona through the weekend. The greatest thunderstorm coverage is expected today, with storms capable of producing high rain rates and flash flooding. Thunderstorm coverage decreases Saturday and Sunday with even less activity to begin next week. && .DISCUSSION...High pressure is centered over the central plains today leaving Arizona in a deep southerly flow. A moist monsoon air mass remains in place which will continue to fuel daytime thunderstorms through the upcoming weekend. Convective showers and storms today have been more widespread and a bit more vigorous across Yavapai and Coconino counties where better instability lies. This area is likely also being influenced by a bit of upper level support from a shortwave across southern Arizona. Shower and storm activity this evening will continue to favor this area. Isolated rainfall rates of 1 inch per hour are likely through this evening and may lead to areas of flash flooding where storms train over the same areas. A Flash Flood Watch remains in effect for Coconino County through midnight tonight. In addition, a few stronger storms may produce brief gusty winds and small hail. Thunderstorm updrafts today have been very short lived and unable to sustain much hail production. Storms are expected to decrease later this evening but the aforementioned shortwave will move northward tonight and this will keep a chance for showers overnight across much of northern Arizona. The overall synoptic scale pattern changes very little over the weekend meaning we will continue to see scattered showers/storms each afternoon. Coverage will decrease slightly each day, but isolated areas of heavy rain and a few stronger storms will be possible. Saturated soils across the area will lead to a flash flood threat in any areas that do receive heavy rainfall. Next week, troughing develops east of the Rockies while a ridge of high pressure strengthens across the western U.S. This will leave Arizona in a drying northerly flow pattern. Expect thunderstorm chances to retreat eastward across the state through the week. Consequently, the building high and more sunshine will also lead to warmer daytime temperatures and our more susceptible low elevations may be nearing Excessive Heat criteria again. Projections for next weekend favor monsoon moisture increasing and spreading north leading to increasing thunderstorm chances. && .AVIATION...For the 00Z package...Scattered thunderstorms will persist through 03Z this evening before decreasing. Most numerous coverage will be west of KFLG. Periods of MVFR/IFR conditions and gusty, erratic winds will occur in and around thunderstorms. Storm coverage will decrease after 03Z, but the chance for a few storms will continue overnight. Expect showers and storms to increase again after 18Z Sat. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered thunderstorms will continue this evening, most widespread in northwestern Arizona. Flash flooding and lightning are the primary hazards. Lesser coverage is anticipated for Saturday and Sunday. Light winds are forecast outside of thunderstorm activity. Monday through Wednesday...Expect a drying and warming trend next week with less thunderstorm coverage each afternoon. && .FGZ WATCHES/WARNINGS/ADVISORIES...Flash Flood Watch until 11 PM MST this evening FOR AZZ004>007-012-015. && PUBLIC...MCT AVIATION...MCT FIRE WEATHER...MCT For Northern Arizona weather information visit weather.gov/flagstaff
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1229 PM MST FRI JUL 30 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1220 PM HAIL 1 ESE DOWNTOWN FLAGSTAF 35.19N 111.63W
07/30/2021 E0.70 INCH COCONINO AZ TRAINED SPOTTER
MARBLE SIZED HAIL.
&&
BEPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1236 PM MST FRI JUL 30 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0300 PM FLOOD 1 ESE MOENKOPI 36.10N 111.20W
07/29/2021 COCONINO AZ OTHER FEDERAL
9.7 FOOT RISE ON THE MOENKOPI GAGE -
STARTING AT 3 PM MST ON 7/29/21 AND PEAKING
AT 445 AM MST ON 7/30/21.
&&
BEPSpecial Weather Statement National Weather Service Flagstaff AZ 301 PM MDT Fri Jul 30 2021 AZZ010-302130- Chinle Valley- 301 PM MDT Fri Jul 30 2021 ...SIGNIFICANT WEATHER ADVISORY FOR APACHE COUNTY UNTIL 330 PM MDT... At 300 PM MDT, Doppler radar was tracking a strong thunderstorm 7 miles southwest of Round Rock, or 19 miles north of Chinle, moving northwest at 15 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Round Rock, Many Farms Lake and Many Farms. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. 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 3640 10941 3632 10960 3645 10977 3658 10946 TIME...MOT...LOC 2100Z 153DEG 13KT 3643 10955 ET
The Flagstaff radar (KFSX), 29 km away, was scanning. The volume nearest the first event began at 22:48 UTC.
1 heavy rain, 1 flash flood, 1 funnel cloud. Local standard time, as filed.
Heavy rain fell 4 miles south of Washington Park with 1.10 inches measured in 40 minutes.
Heavy rain caused flash flooding from Washington Park to Tonto Village. Water was cascading through yards and flooding roadways. The East Verde River rose 3 feet near Washington Park at 540 PM MST.
A picture of a funnel cloud from the community of Pinon was posted on Social Media.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings 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: 980432, 980435, 980436.