A surge of monsoonal moisture pushed north across Arizona. This allowed a thunderstorm to develop and it produced severe hail.
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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.
A surge of monsoonal moisture pushed north across Arizona. This allowed a thunderstorm to develop and it produced severe hail.
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 1, 2:43 PM MST, 2 hours 37 minutes earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 243 PM MST Sat Aug 1 2020 .SYNOPSIS...Hot temperatures and mostly dry conditions can be expected across much of northern Arizona through Sunday. Shower and thunderstorm chances will mainly be limited to the White Mountains with only isolated storms possible elsewhere through Tuesday. More widespread showers and thunderstorms are possible by Thursday. && .DISCUSSION...Another hot day across northern Arizona as strong high pressure remains in control of the weather. We have seen dewpoints climbing along and south of the Mogollon Rim as a surge of monsoonal moisture has pushed north through the day. This has helped to keep things a couple degrees cooler than the past couple days in some locations. Additionally, we have seen a fair bit of cumulus development as well as isolated to scattered thunderstorm activity. The main hazards with the stronger storms has been gusty winds, locally heavy rainfall, and hail. Enhanced shear across southern Apache and Navajo counties has led to strong storms capable of producing large hail. Shower and storm activity will continue to be most widespread across eastern Arizona through this evening. We should see things gradually diminish after sunset. Some moisture will remain in place on Sunday for another round of isolated storm activity. Current thinking is we will see a bit less activity than today. With the lack of deep moisture, gusty winds will remain the primary hazard. Daytime temperatures will continue a gradual cooling trend with highs expected to be a couple degrees cooler than today. High pressure will weaken and shift south on Monday and Tuesday, bringing dry westerly flow back into much of the area. This will limit any thunderstorm chances to the White Mountains. We could see the high position itself in a more favorable position after mid-week to at least get some monsoon moisture back into the area. However, latest long range guidance is pessimistic on this being anything more than a brief, slight uptick in activity. We will continue to keep an eye on it. && .AVIATION...For the 00Z package...Expect mainly VFR conditions for the 24 hour TAF forecast period. ISOLD-SCT SHRA/TSRA this afternoon near sites KFLG/KPRC/KINW, but mainly east of KFLG and along the Mogollon Rim and White Mtns. Any stronger cells could produce MVFR conditions and wind gusts from 35-45kts. Sfc winds outside of storms SW-W5-15G20KT during the afternoon hours. Storms dissipating after 02Z Sunday. Lesser storm coverage is expected on Sunday. Aviation discussion not updated for amendments. && .FIRE WEATHER...Hot weather will continue into early next week as high pressure remains over Arizona. Daytime showers and thunderstorms are expected, though coverage will not be widespread. Winds will generally be light except in the vicinity of storms. Tuesday through Thursday...Temperatures will drop back to near normal through this period. Moisture will mainly be confined to the White Mountains on Tuesday before expanding westward for Wednesday and Thursday. && .FGZ WATCHES/WARNINGS/ADVISORIES...Excessive Heat Warning until 8 PM MST Sunday FOR AZZ005-018-037- 038. Excessive Heat Warning until 8 PM MST Tuesday FOR AZZ006. && PUBLIC...TPS AVIATION...KD FIRE WEATHER...KD For Northern Arizona weather information visit weather.gov/flagstaff
Special Weather Statement National Weather Service Flagstaff AZ 111 PM MST Sat Aug 1 2020 AZZ016-018-012100- Northern Gila County-Eastern Mogollon Rim- 111 PM MST Sat Aug 1 2020 ...SIGNIFICANT WEATHER ADVISORY FOR GILA AND NAVAJO COUNTIES UNTIL 200 PM MST... At 109 PM MST, Doppler radar was tracking a strong thunderstorm 15 miles south of Aripine, or 20 miles southeast of Forest Lakes, moving south at 15 mph. Pea size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Cibecue. 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 3428 11057 3424 11036 3391 11040 3398 11072 TIME...MOT...LOC 2009Z 014DEG 12KT 3419 11049 DB
Special Weather Statement
National Weather Service Flagstaff AZ
207 PM MST Sat Aug 1 2020
AZZ007-015-012130-
Western Mogollon Rim-Coconino Plateau-
207 PM MST Sat Aug 1 2020
...SIGNIFICANT WEATHER ADVISORY FOR COCONINO COUNTY UNTIL 230 PM
MST...
At 206 PM MST, Doppler radar was tracking a strong thunderstorm 12
miles southwest of Williams, or 26 miles northeast of Chino Valley,
moving east at 15 mph.
Half inch hail and wind gusts up to 50 mph will be possible with this
storm.
This storm will remain over mainly rural areas of Coconino County.
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 3517 11231 3520 11208 3499 11214 3502 11233
3516 11233
TIME...MOT...LOC 2106Z 280DEG 13KT 3511 11228
DBThe Flagstaff radar (KFSX), 59 km away, was scanning. The volume nearest the first event began at 00:18 UTC.
1 hail. Local standard time, as filed.
A thunderstorm produced one inch diameter hail on Silver Road in Camp Verde.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2020Every state in 2020This day in weather historyWarnings in Arizona, August 2020
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: 912886.