Similar to the 20th, thunderstorms once again initiated across the northern Arizona high terrain during the afternoon of the 21st, though more focused along the Mogollon Rim compared to the day prior. Increased steering flow allowed for thunderstorms to move off of the Rim and toward the lower elevations.
Every event with a place to put it; 1 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.
Similar to the 20th, thunderstorms once again initiated across the northern Arizona high terrain during the afternoon of the 21st, though more focused along the Mogollon Rim compared to the day prior. Increased steering flow allowed for thunderstorms to move off of the Rim and toward the lower elevations. High instability (MUCAPE 2,000-2,500 J/kg) helped thunderstorms maintain intensity as they travelled toward the lower deserts. Given the greater steering flow, faster thunderstorm motion helped abate flash flood impacts. Greater shear across northwest Arizona allowed an organized complex of thunderstorms to develop during the evening hours before progressing through southwest Arizona and the Lower Colorado River Valley area, producing severe wind gusts and dense blowing dust into the early morning hours on the 22nd. No injuries were reported.
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 21, 4:42 PM MST, 18 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 442 PM MST Sun Aug 21 2022 .UPDATE...Updated 00z Aviation Discussion... && .SYNOPSIS... Another chance for storms mainly across Maricopa, northwest Pinal, and La Paz counties between 3 pm and 10 pm today. Isolated severe winds will be possible. Storm chances trend lower Monday before increasing again by Wednesday. Another downtrend in storm chances by the end of next week. Temperatures will follow a similar trend but with higher temperatures on days with lower storm chances. Overall, temperatures are anticipated to be below normal. && .DISCUSSION... Phoenix ended up breaking its daily precipitable water record once again today, with 1.95 inches observed in this mornings sounding. In addition, surface dew points are in the upper 60s to lower 70s across our deserts. Although we have seen some drying over the past 24 hours, it remains evident that we still have plenty of moisture in the atmosphere today. In terms of the synoptic pattern, the mid-level flow is more out of the north- northeast today and that disturbance that brought us a substantial amount of rainfall over the past few days is also going to be forced eastward over the next 24 hours. For the remainder of the day, hi-res guidance continues to suggest that convection will continue developing along the rim this afternoon, with activity then propagating southwestward into south-central Arizona and parts of southwest Arizona and the Colorado River Valley. Outflows from this activity are most likely to move into the lower deserts after 3 pm. There should be plenty of instability to support additional storms as these outflows push through, with the mesoscale analysis page forecasting greater than 2000 j/kg of mlcape this afternoon. The best chances for storms will be across south-central Arizona and in La Paz county in southwest Arizona. Slightly drier air will increase the damaging wind risk and lower the flood risk slightly compared to yesterday. The probability of getting greater than 35 mph winds is around 70% in the Phoenix area, greater than 50% across northwest Pinal and the rest of Maricopa county, and greater than 30% across southwest Arizona. In addition, isolated severe winds (greater than 58 mph) will be possible, and due to this there is a marginal risk of severe storms mainly across Maricopa (including the Phoenix metro), northwest Pinal, and La Paz counties. Due to the potential for strong winds, blowing dust will also be a risk in dust prone areas. With slightly faster storm motion and slightly less moisture in the atmosphere, the chance of getting more than 3” of rainfall in 3 hours is less than 10% (for reference, the chance was 10-30% the past few days). However, even though the Flood Watch isn’t in effect today, localized flooding will still be possible with any storm. Further west in southeast California, regardless of moisture, this pattern isn’t necessarily the most favorable for storms out there. The best chances will be across JTNP, where an isolated storm can’t be ruled out this afternoon. High pressure to our west starts to move eastward, drying us out a little more and increasing 850 mb temps approximately 5 degrees tomorrow. Our flow will remain out of the north-northeast, and we can expect a similar story tomorrow, but with less moisture and more limiting temperatures aloft. HREF is showing less convection firing off along the rim by the early afternoon. Activity and associated outflows will once again try to propagate towards the lower deserts but with less support, storms look like they will struggle to survive. It’s possible that a few isolated storms develop, but coverage looks to be substantially less than what we’ve seen the past few days. The chance for getting greater than 35 mph wind speeds lowers to 10-30% across south-central Arizona and generally around 10% or less across the western deserts. The best time frame for outflows and isolated convection would be between 3 and 10 pm, with the best coverage across the high terrain north and east of Phoenix. The flow turns more easterly Tuesday into Wednesday as the high starts to shift towards the 4 corners. 850 mb temps are warmest with the center of the high closest on Tuesday. PWs drop more across our forecast area as well on Tuesday, and only isolated storms look possible, favoring south-central Arizona. Wednesday currently looks like it will be another good day for lower desert storms, even as far west as southeast California. Moisture increases once again and our flow is a lot more favorable. Definitely something we will continue to keep an eye on. Low confidence on the forecast beyond Wednesday, but it does appear that Thursday could be active again and then we start to slowly dry out and warm up again towards the weekend as our flow turns more westerly. Below normal temps will continue for at least the next week with minor heatrisk across south-central and southwest Arizona and minor to moderate heatrisk across southeast California. && .AVIATION...Updated 2335Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Watching several clusters of strong thunderstorms across Yavapai County moving southward towards the valley. Confidence of any thunderstorm directly affecting the terminals remains low and thus VCTS continues to be reflected in the latest TAF package issuance. However, there is higher confidence of outflow winds from the north from these thunderstorms affecting the terminals with timing expected to be between 01z and 03z for impacts. There continues to be a greater than 50% probability of winds exceeding 30 knots and about a 5% probability of winds exceeding 50 knots with these outflows. As these storms continue to inch closer to the area, cloud cover coverage will increase to SKN-BKN with bases aoa 5-7 kft. Conditions should improve by late evening with light and variable winds likely into the overnight with an easterly switch early Monday morning. A westerly shift is anticipated by late morning into the early afternoon. Thunderstorm potential and associated outflow impacts appears lower for Monday afternoon/ evening, with a 10-30% probability of winds exceeding 30 knots. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns expected through the period. Prevailing wind direction will be from the southeast at KIPL and from the south at KBLH with speeds generally around 10 kts. Cloud coverage will generally be FEW to locally SCT with bases aoa 15 kft. && .FIRE WEATHER... Very elevated moisture with min RH values >30-50% today with excellent overnight recoveries >65-80% across the region. Storm chances will be greatest across the rim north and east of the Phoenix metro today, however, isolated to scattered storms will be possible in the lower deserts of south-central & southwest AZ as this activity propagates southward. Winds on average will be light, with the exception of any thunderstorm or associated outflows generating stronger gusts. Well below normal max Ts today. Drier and slightly warmer conditions with a downtick in storm activity is likely tomorrow before another uptick by midweek. Much drier conditions are then forecast by next weekend with min RH values in the lower deserts generally less than 30%. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...Feldkircher AVIATION...Lojero FIRE WEATHER...Feldkircher
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1225 PM MST SUN AUG 21 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0830 PM TSTM WND DMG 9 SW WITTMANN 33.67N 112.63W
08/20/2022 MARICOPA AZ TRAINED SPOTTER
***DELAYED REPORT*** MULTIPLE TREES UPROOTED
OR BROKEN. SOME TREES FELL TOWARD PROPERTY
AND ONTO WALLS.
&&
JMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
1247 PM MST SUN AUG 21 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0425 AM FLASH FLOOD 3 WNW WICKENBURG 33.98N 112.77W
08/21/2022 MARICOPA AZ COUNTY OFFICIAL
***DELAYED REPORT*** VULTURE MINE RD
IMPASSABLE DUE TO A FLASH FLOOD OF DEPTH 8.5
FT AT ITS PEAK.
&&
JMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
323 PM MST SUN AUG 21 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1240 PM FLASH FLOOD 2 WSW MIAMI 33.38N 110.91W
08/20/2022 GILA AZ PUBLIC
***DELAYED REPORT*** VIDEO SHOWING
CONSIDERABLE FLOODING IN BLOODY TANKS,
AROUND BANK FULL.
&&
JMPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PHOENIX AZ
328 PM MST SUN AUG 21 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1100 PM FLASH FLOOD 3 SSE WITTMANN 33.74N 112.50W
08/20/2022 MARICOPA AZ DEPT OF HIGHWAYS
***DELAYED REPORT*** DOT CLOSED PATTON RD
FROM 203RD AVE TO 195TH AVE DUE TO FLOODING.
&&
JMSpecial Weather Statement
National Weather Service Phoenix AZ
428 PM MST Sun Aug 21 2022
AZZ545-547-557-220000-
New River Mesa AZ-Mazatzal Mountains AZ-Rio Verde/Salt River AZ-
428 PM MST Sun Aug 21 2022
...A strong thunderstorm will impact portions of Gila and Maricopa
Counties through 500 PM MST...
At 427 PM MST, Doppler radar was tracking a strong thunderstorm near
Horseshoe Reservoir, or 9 miles northwest of Sycamore Creek, moving
south at 5 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...
Sycamore Creek, Sunflower, Camp Creek and Horseshoe Reservoir.
This includes AZ Route 87 between mile markers 217 and 228.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
If on or near Horseshoe Lake, get out of the water and move indoors
or inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 3398 11141 3386 11139 3383 11159 3386 11183
3401 11179 3400 11150 3401 11148 3401 11143
TIME...MOT...LOC 2327Z 356DEG 5KT 3401 11162
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
INSThe Phoenix radar (KIWA), 73 km away, was scanning. The volume nearest the first event began at 00:04 UTC.
7 thunderstorm wind, 1 flood, 1 dust storm. Local standard time, as filed.
A video showed high flow in Tonto Creek made unbridged crossings across the creek impassable. An upstream USGS stream gage along the creek climbed above action stage, peaking at a depth of 5.62 feet at 1915MST. No damage or injuries were reported.
A large tree fell between two parked vehicles at a condominium at Roosevelt Street and Granite Reef Road. Timing estimated from radar. No injuries were reported.
ADOT webcams in Parker showed near zero visibility due to dense blowing dust. No accidents or injuries were reported.
Yuma Proving Ground Station 6 mesonet recorded a 64 mph gust.
Yuma Proving Ground Station 173 mesonet recorded a 58 mph gust.
Yuma Proving Ground Station 17 mesonet recorded a 61 mph gust.
Yuma Proving Ground Station 33 mesonet recorded a 58 mph gust.
A shed was blown into nearby power lines, causing a power pole to come down. Timing estimated from radar. No injuries were reported.
Power poles were reported down near 12th Street and Pacific Avenue. Timing estimated from radar. No injuries were reported.
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: 1054619, 1054618, 1054626, 1054623, 1054625, 1054624, 1054622, 1054620, 1054621.