Thunderstorm activity developed across much of eastern AZ, along the higher terrain features, during the early afternoon hours. Outflow boundaries emanating from the activity over the higher terrain areas sparked a complex of robust thunderstorms over Pinal County.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 PSR wrote it up.
Thunderstorm activity developed across much of eastern AZ, along the higher terrain features, during the early afternoon hours. Outflow boundaries emanating from the activity over the higher terrain areas sparked a complex of robust thunderstorms over Pinal County. A northwestward moving outflow boundary that developed from the Pinal County storms produced wind gusts in excess of 50 mph as well as areas of dense blowing dust across the Phoenix East Valley. Additional thunderstorm activity then developed over central Phoenix during the late afternoon, likely instigated by a convergence zone that set up right over the area with little convective inhibition in place and thus it did not take much of a triggering mechanism to get convective initiation. With MLCAPE values of 1000-1500 J/KG along with DCAPE of around 1500 J/KG, conditions were favorable for the generation of strong to severe downburst winds.
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 Phoenix, AZ wrote its last area forecast discussion before the first event at Aug 22, 12:25 PM MST, 1 hour 55 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 1225 PM MST Thu Aug 22 2024 .SYNOPSIS... Elevated chances for showers and thunderstorms will linger through today before much drier air takes over during the weekend, limiting further precipitation activity for at least several days. Afternoon high temperatures should remain at or slightly above normal for most locations through the middle of next week. && .DISCUSSION... Changes in the overall pattern are in store as we go through the next day or so as a deep area of low pressure begins to dive along the Pacific Coast, nudging the sub-tropical high further east toward central Texas and ushering in much drier air over the Desert Southwest. However, before this dry air becomes fully engulfed over the region, enough lingering moisture should be available to promote shower and thunderstorm activity this afternoon, primarily for south-central and southeastern Arizona. The axis of greatest instability is expected to set up from the Phoenix metro eastward, with MLCAPE values approaching 1000-1500 J/kg. Model soundings indicate weak, to almost no capping over these areas, so convective initiation should be easily achieved, especially around enhanced terrain features due to orographic influences. With this relatively uncapped environment in place, further convective development over lower desert areas of Pinal and eastern Maricopa Counties is expected, but will be heavily dependent on strong outflows from distant activity. Though the thermodynamic profile for areas in La Paz and western Maricopa Counties will not be as impressive compared to the areas stated above, some isolated thunderstorms cannot be ruled out. The main hazards with potential convection will be strong winds and blowing dust that could result in hazardous travel conditions. HREF probabilities for wind gusts exceeding 35 mph currently stands at 50-70% for much of south-central Arizona, with a slight chance (~10%) of severe wind gusts (>58 mph) highlighted over Pinal and far southeastern Maricopa Counties. Flooding will also be concern under heavier or training thunderstorms. The greatest potential (at least a 15% chance) of seeing excessive rainfall will be focused over far eastern Gila County, but it is not out of the question to see localized flooding impacts elsewhere. By Friday, negative PWAT anomalies will begin to encompass most of our forecast area as the dry air associated with the above- mentioned trough continues to advance eastward, resulting in a decrease in rainfall activity for most of the region. The one exception to this would be Gila County where residual moisture may help spark some terrain driven convection. Continued drying into the weekend will lead to a further downtrend in rainfall potential, with the best chances becoming focused outside of our CWA over far southeastern Arizona and the White Mountains. Daytime highs over south-central and southwestern Arizona will remain mostly steady over the next few days, ranging generally between 102-107 degrees over lower desert areas. Temperatures over the deserts of southeastern California during this window of time may drop a few degrees due to closer proximity to the Pacific trough. Afternoon highs out there today will be between 105-108 degrees, while readings between 100-105 will be common during the weekend. Looking toward next week, model clusters are not in complete agreement with how the pattern will evolve. There are some hints that the sub-tropical high will shift back closer to the Desert Southwest once again, switching flow back out of the southeast and thus increasing moisture advection. However, other models point toward a continuation of southwesterly flow that would keep conditions dry and limit rain chances during the this timeframe. As of now, it appears that the drier solution is favored, but any subtle shifts in the coming days could result in a much different forecast. Nonetheless, it appears likely that temperatures will hover near to slightly above normal, with the NBM showing lower desert highs between 101-109 degrees through much of the upcoming week. && .AVIATION...Updated at 1740Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: The potential for thunderstorm activity as well as associated outflows will be the main weather issues heading into this evening. In the meantime, through the mid-afternoon hours, winds will be on a gradual process of switching out of the west to southwest with a period of southerly crosswinds likely during the westerly shift. Speeds will generally remain aob 10 kts, although some occasional gusts into the mid to upper teens cannot be ruled out. Thereafter, heading into the mid to late afternoon hours, thunderstorm activity is expected to develop to the east and southeast of the Phoenix metro with the potential for more isolated activity to develop over the proper Phoenix metro. Given that the overall thunderstorm coverage within the Phoenix area will remain more sparse, only VCTS continues to be mentioned for the TAFs at this time with the best chances for any TSRA impacts between 23-01z. There is a strong signal within the hi-res guidance that activity to the south and east of Phoenix will likely send a predominant outflow from east to southeast, with gusts potentially exceeding 20-30 kts. Conditions are expected to improve after 02-03z, with wind directions likely prevailing out of the east to southeast through the overnight hours and most of Friday morning. FEW-SCT mid to high clouds will prevail through early this afternoon before increasing to SCT-BKN by later this afternoon as the overall convective coverage increases. Southeast California/Southwest Arizona including KIPL and KBLH: No major weather issues under occasional mid/high cloud decks will exist through the TAF period. At KIPL, winds through the late afternoon will prevail out of the southeast before shifting to a westerly sundowner component by early this evening. At KBLH, winds will generally prevail out of the south. Occasional gusts upwards of 20-25 kts are likely at KBLH through this afternoon, and potentially for KIPL early this evening. && .FIRE WEATHER... Scattered showers and thunderstorms will be possible this afternoon and evening across southcentral AZ with a better chance for wetting rainfall over the higher terrain areas N and E of Phoenix. Some storms could produce locally heavy rainfall over recently burned areas. Rain chances will begin to diminish on Friday with dry conditions setting in by this weekend. Min RH's will remain above 20% across the eastern districts and fall to 15% or lower across the western districts this afternoon. Further drying on Friday will result in widespread min RH at or below 15% across the lower deserts. Outside of any thunderstorm related outflows, winds will generally continue to follow typical diurnal tendencies with some afternoon gusts upwards of 20-25 mph. Temperatures will continue to remain at or slightly above normal for the next several days. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...RW AVIATION...Lojero FIRE WEATHER...Salerno
Special Weather Statement
National Weather Service Phoenix AZ
136 PM MST Thu Aug 22 2024
AZZ537-540-544-222115-
Buckeye/Avondale AZ-Northwest Valley AZ-North Phoenix/Glendale AZ-
136 PM MST Thu Aug 22 2024
...A STRONG THUNDERSTORM WILL IMPACT MARICOPA COUNTY THROUGH 215 PM
MST...
At 136 PM MST, Doppler radar was tracking a strong thunderstorm over
Cashion, moving north at 15 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Phoenix, Glendale, Surprise, Avondale, Goodyear, El Mirage, Tolleson,
Youngtown, Waddell, Cashion, Sun City, Litchfield Park, Glendale
Sports Complex, Luke AFB, Phoenix International Raceway, Downtown
Peoria, Downtown Glendale, and Camelback Ranch.
This includes the following highways...
AZ Interstate 10 between mile markers 126 and 140.
AZ Interstate 17 between mile markers 206 and 207.
US Highway 60 between mile markers 151 and 159.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3333 11221 3338 11242 3361 11240 3356 11210
TIME...MOT...LOC 2036Z 194DEG 13KT 3343 11230
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
GLSpecial Weather Statement
National Weather Service Phoenix AZ
206 PM MST Thu Aug 22 2024
AZZ547-552-553-555>558-560>563-230000-
Southeast Gila County-Mazatzal Mountains-Tonto Basin-Northwest Pinal
County-San Carlos-Apache Junction/Gold Canyon-Dripping
Springs-Globe/Miami-Superior-Rio Verde/Salt River-Pinal/Superstition
Mountains-
206 PM MST Thu Aug 22 2024
...STRONG THUNDERSTORMS EXPECTED ACROSS GILA...MARICOPA AND PINAL
COUNTIES...
At 201 PM MST, radar indicated clusters of thunderstorms developing
across the higher terrain areas of Pinal, eastern Maricopa and Gila
Counties. Expect any thunderstorms that develop to produce downburst
winds up to 50 mph, small to medium size hail, and dangerous cloud
to ground lightning. Torrential rainfall can also be expected that
can lead to localized flooding. The thunderstorm threat will
continue into the early evening hours.
Locations impacted include...
Florence, Globe, Superior, Hayden, Christmas, Roosevelt, San Carlos,
Miami, Cutter, Hilltop, Roosevelt Dam, Top-Of-The-World, Sawmill,
Florence Junction, Queen Valley, Central Heights-Midland City, Tonto
National Monument, Four Peaks, Apache Lake, and Boyce Thompson
Arboretum.
This includes the following highways...
US Highway 60 between mile markers 211 and 298.
AZ Route 87 between mile markers 226 and 228.
AZ Route 70 between mile markers 253 and 271.
&&
LAT...LON 3347 11017 3339 11044 3329 11046 3320 11040
3315 11063 3299 11077 3324 11094 3300 11133
3396 11144 3396 11137 3380 11115 3376 11099
3364 11092 3368 11084 3366 11078 3379 11068
3385 11056 3383 11033 3360 11000 3346 11000
TIME...MOT...LOC 2101Z 192DEG 13KT 3342 11077
GLThe Phoenix radar (KIWA), 63 km away, was scanning. The volume nearest the first event began at 21:18 UTC.
14 thunderstorm wind, 3 dust storm, 1 hail, 1 flood. Local standard time, as filed.
Penny sized hail reported along Highway 60 at Top of the World. No damages nor injuries were reported.
Downed powerlines reported on SR-287, between Main St and Valley Farms Rd in Florence, leading to a closure of the highway. No injuries were reported.
Webcam showed visibility reduced to around one quarter mile near Ironwood Road and Pecos Road near Queen Creek due to dense blowing from thunderstorm outflow winds. No accidents nor injuries were reported.
Visibility of around 1/4 mile in the area of Ironwood Road and Gateway Road near Queen Creek due to dense blowing dust from thunderstorm outflow winds. No accidents nor injuries were reported.
Power lines down in several sectors of Apache Junction. Wind gusts were estimated upwards of 55-60 mph. No injuries were reported.
A 64 mph wind gust was measured at Phoenix Sky Harbor Airport.
Webcam showed reduced visibility below one quarter mile along the Superstition Freeway and Gilbert Road due to dense blowing from thunderstorm outflow winds. No accidents nor injuries were reported.
An adult male was found deceased due to drowning at Canyon Lake. The man was paddle boarding at the time the thunderstorm was approaching and fell off the paddleboard likely due to the strong winds and higher waves. A surface observing site located at Canyon Lake measured a peak gust of 40 mph.
A large uprooted tree fell inside an apartment complex located in the area of Loop 202 and Priest Drive in Tempe. Wind gusts were estimated upwards of 60-70 mph. Timing estimated from radar. No injuries were reported.
A very large tree fell and damaged the roof of a home in the area of 60th street and Vernon Avenue in Scottsdale. Wind gusts were estimated upwards of 60-70 mph. Timing estimated from radar. No injuries were reported.
Several uprooted trees along 52nd St between McDowell and Thomas Roads, including one tree falling on a vehicle at Arcadia Montessori in Scottsdale. Wind gusts were estimated upwards of 60-70 mph. No injuries were reported.
Thunderstorm downburst winds broke a window at the Maricopa County Department of Emergency Management facility as well as shattered a window of a vehicle. Wind gusts were estimated upwards of 60-70 mph. No injuries were reported.
Large uprooted tree crashed through a concrete brick wall along Ray Road between 44th and 48th Street in Ahwatukee. Wind gusts were estimated upwards of 60-70 mph. Time estimated from radar. No injuries were reported.
Several downed mesquite and palo verde trees along a shopping center located in the area of Ray Road and 48th street in Ahwatukee. Some of the downed palo verde trees struck some vehicles causing minor damage. Wind gusts were estimated upwards of 60-70 mph. No injuries were reported.
Large tree fell over and took out a light pole in front of an IHOP Restaurant located in the area of Ray Rd and 50th Street in Ahwatukee. Wind gusts were estimated upwards of 60-70 mph. No injuries were reported.
Multiple large trees downed in the area of 48th street and Warner Road in Ahwatukee. Wind gusts were estimated upwards of 60-70 mph. No injuries were reported.
Power lines down in the area of Camelback Road and North 56th Street in Scottsdale. Wind gusts were estimated upward of 60-70 mph. Timing estimated from radar. No injuries were reported.
Downed trees in the area of Shea Boulevard and Loop 101 in Scottsdale. Wind gusts were estimated upwards of 55-60 mph. No injuries were reported.
The Maricopa County Flood Control District Gauge located along Indian Bend Wash at McDonald Drive in Scottsdale measured water levels rising above the alarm stage level of 2.08 feet at around 7:50 PM MST on the 22nd and staying above that level through the next several hours before falling below alarm stage at around 6:50 AM MST on the 23rd. Therefore, several low-level water crossings intersecting the wash downstream likely had flooding with the most significant impacts occurring along Roosevelt Street, where there was a video of a vehicle driving into the wash and stalling. No significant damages nor injuries were reported.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Thunderstorm Wind, Maricopa | 2024-08-22 | 26 | Male | In Water | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2024Every state in 2024This day in weather historyWarnings in Arizona, August 2024
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: 1206100, 1206101, 1206315, 1206323, 1206316, 1206320, 1206318, 1206319, 1206410, 1206341, 1206351, 1206413, 1206326, 1206356, 1206379, 1206357, 1206354, 1206411, 1206418.