The remnant mid-level circulation of what was Tropical Cyclone Kay was located over southern California. 5 and MLCAPE values peaking at around 1000 J/KG.
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.
The remnant mid-level circulation of what was Tropical Cyclone Kay was located over southern California. This led to southerly flow across Arizona, which helped increased moisture and instability with moisture values peaking at around 1.5 and MLCAPE values peaking at around 1000 J/KG. Strong to severe thunderstorms developed across southeast Arizona, near the Tucson area, during the late afternoon hours of the 11th and then progressed northward towards the Phoenix metro during the evening hours, resulting in widespread severe downburst winds and blowing dust as well as isolated flash flooding. The Phoenix Sky Harbor Airport reported a peak wind gust of 86 mph at 2053 MST. Additional storms then developed across western Maricopa County, extending into La Paz County, during the early morning hours of the 12th with heavy rainfall leading to flash flooding become the biggest threat.
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 Sep 11, 3:57 PM MST, 3 hours 22 minutes earlier.
Area Forecast Discussion National Weather Service Phoenix AZ 357 PM MST Sun Sep 11 2022 .UPDATE...UPDATED 00Z AVIATION DISCUSSION. && .SYNOPSIS... The threat for showers and thunderstorms over the next couple of days will gradually shift eastward through Arizona with the most impactful, stronger storms occurring Monday. However, even this evening, strong winds, locally dense blowing dust, and isolated areas of heavy rainfall and flooding will all be concerns. Much drier air will push into the region during the middle and latter half of the week, essentially ending the storm chances. Temperatures will hover slightly below normal through the first half of the week before rebounding near to slightly above normal by late week into the weekend. && .DISCUSSION... Early afternoon WV satellite imagery shows the remnant subtropical circulation of Kay still wobbling off the southern California coast undergoing another transition to an extratropical cyclone as dry midtropospheric has completely cutoff any tropical influence. Meanwhile, a progressive upstream trough and associated strong zonal jet will act as the impetus to open and absorb this system into westerly flow dipping towards the SW Conus. With this system starting to move and attempting to dislodge a blocking ridge, a seasonally robust, meridional 35kt H5 jet has developed on its eastern periphery through Arizona. One shortwave can be seen lifting north through the Lower Colorado River Valley while other vorticity centers appear to be sheared along the jet axis riding north from Mexico providing favorable ascent structure across much of the CWA. Recent objective analysis depicts modest drying through the environment since yesterday as both total column PWATs and low level mixing ratios have retreated slightly. However, a solid 11-14 g/kg are still locked into lower elevations, and more than sufficient to support storm maintenance off higher elevations. The key may be the vertical distribution of moisture towards the top of the boundary layer where recent dry SW flow has eroded the higher quality moisture; and models only partially mix above 800mb such that CinH may remain on the order of 25 J/kg at peak heating. Nevertheless, the combination of both MLCape and DCape 1000-1500 J/kg coincident in an environment favorable for ascent should result in scattered thunderstorm clusters. Aside from a few showers and embedded storms lifting across southeast CA in moist upslope flow this afternoon, the main emphasis of hi-res modeling has consistently been semi-organized storm clusters congealing over Pima/Pinal counties and belching deep outflow boundaries north towards the Phoenix metro. The majority of HREF membership suggests a singular large outflow (likely replete with blowing dust) surging through the central CWA, but with varying amounts of post-outflow storms erupting. Given the inhibition likely present, it might take more than one outflow boundary to breach the capping around the Phoenix area, however rarely is there just one outflow as depicted by most CAMs. Thus, 40-60% storm coverage as suggested by NBM POPs seems adequate, though with the boundaries advancing at a good clip, many locations may be limited on the total amount of rainfall. Another facet of the forecast with a recurring similar solution among modeling groups is the combination of outflows propagating into western AZ, some semblance of northward advancing low level moisture from NW Mexico, and shortwave energy encapsulated on the nose of a 35kt jet punching north and east producing additional clusters of elevated storms overnight near or just east of the Colorado River. Though speed shear may keep these clusters advancing north our of the forecast area, these types of synoptic setups have occasionally resulted in expansive flooding due to backbuilding convection training over the same area. HREF members hint at this evolution, but offer a wide variety of possible outcome leading to a lower confidence forecast; and with national centers highlighting only minimal excessive rainfall risk, will hold off on any headlines. Monday forecasts continue to trend towards greater storm coverage in the eastern part of the forecast area as synoptic scale forcing and increasing jet energy become juxtaposed with a favorable thermodynamic environment. While there is some question as to the impact of overnight storms and ability for the atmosphere to recover, forecast BUFR soundings continue to show steady cooling aloft (H5 temperatures falling around -8C) resulting in H7-H5 lapse rates rebounding closer to 7 C/km. As a result, both MLCAPE and DCape values should once again range between 1000-1500 J/kg. Overall, soundings this afternoon and Monday do not look dissimilar, with the exception of far more robust 0-6km bulk shear of 25-30kt. While marginal for organized or supercellular storms, this shear/instability combination should easily support isolated strong to severe thunderstorms from Maricopa County eastward. Strong wind gusts, expansive blowing dust, and small hail would be expected along with brief heavy downpours. Localized flash flooding is also possible, but may be conditional on the requirement of cluster interactions given the bulk shear and forward propagation tendency. By Tuesday, pronounced westerly flow begins to settle over the majority of the forecast area drying things considerably such that the storm activity will be mostly confined to higher terrain north and east of Phoenix. Since it will take more than one day to completely scour moisture, can not rule out a few showers/storms popping over valley terrain features and foothills, but with little to no major impacts. During the middle to latter half of the week, broad troughing and a strong 75kt zonal jet sweeps across the SW Conus dislodging any remaining quality moisture. There are excellent indications boundary layer mixing ratios fall below 8 g/kg and PWATS hover in a 0.75-1.00 inch range essentially precluding any deep convection throughout the entire region. During this drying regime, H5 heights will build back near 590dm yielding temperatures back into a normal to slightly above normal range by the end of the week. && .AVIATION...Updated 2300Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Southeasterly flow is attempting to switch to southwest. This should continue for the next couple of hours. Sometime between 2-4Z thunderstorms are expected to move out of the southeast and into the Phoenix area bringing gusty winds, areas of blowing dust, and isolated heavy rain/lightning. Storms should clear out of the area by 6Z. For now VCTS is maintained in the TAF due to low confidence in the exact timing but may be upgraded to TS with time. Another slight chance of showers develops by daybreak but will likely remain west of the area. Winds during the overnight hours will mostly be out of the southeast. Winds will switch back to southwest during the day Monday with scattered showers and storms developing by the early afternoon. Clouds should mostly remain at or above 8 kft. Southeast California/Southwest Arizona including KIPL and KBLH: Current thunderstorm activity in southeast California is expected to remain too few and far between to impact TAFs. Later today, storms over the San Diego County mountains and far northern Baja could possibly produce some outflow that reaches KIPL early this evening but anticipate wind speeds to remain light if it happens. Late tonight, an outflow boundary from the east will likely cause a easterly wind shift at KBLH. Additional shower and isolated storm development is possible at KBLH as this outflow pushes through. Best time frame would be between 8Z and 12Z tonight. Otherwise, anticipate light winds with some late morning and afternoon cumulus (bases AOA FL050) at both terminals. && .FIRE WEATHER... The threat for showers and thunderstorms will shift towards central and eastern Arizona during the next couple of days, with Monday being the day with the greater coverage. Thereafter, by the middle and latter of the week into at least next weekend, considerable drying is expected, which will essentially end the storm chances everywhere. MinRHs will range between 30-45% through Tuesday and then fall to between 20-30% by the middle to latter half of the week, potentially falling below 20% by next weekend. Winds for the most part will generally remain light through the period with the exception of thunderstorm outflows generating stronger gusts. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && DISCUSSION...18/Lojero AVIATION...Hodges/Feldkircher FIRE WEATHER...Lojero
Special Weather Statement
National Weather Service Phoenix AZ
551 PM MST Sun Sep 11 2022
AZZ539-559-120130-
Sonoran Desert Natl Monument AZ-Gila Bend AZ-
551 PM MST Sun Sep 11 2022
...A strong thunderstorm will impact portions of Maricopa County
through 630 PM MST...
At 550 PM MST, Doppler radar was tracking a strong thunderstorm 10
miles southeast of Sentinel, or 24 miles southwest of Gila Bend,
moving north at 35 mph.
HAZARD...Wind gusts up to 50 mph and half inch 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...
Sentinel.
This includes AZ Interstate 8 between mile markers 83 and 108.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3265 11289 3263 11323 3295 11332 3304 11284
TIME...MOT...LOC 0050Z 179DEG 31KT 3281 11306
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
HirschSpecial Weather Statement
National Weather Service Phoenix AZ
630 PM MST Sun Sep 11 2022
AZZ554-559-120230-
Sonoran Desert Natl Monument AZ-West Pinal County AZ-
630 PM MST Sun Sep 11 2022
...A strong thunderstorm will impact portions of Maricopa and Pinal
Counties through 730 PM MST...
At 629 PM MST, Doppler radar was tracking a strong thunderstorm over
Big Horn, or 17 miles southeast of Gila Bend, moving north at 15 mph.
HAZARD...Winds in excess of 40 mph and half inch 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...
Estrella, Sonoran National Monument, Freeman and Big Horn.
This includes the following highways...
AZ Interstate 8 between mile markers 127 and 144.
AZ Route 238 between mile markers 10 and 23.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3267 11236 3272 11256 3305 11254 3298 11216
TIME...MOT...LOC 0129Z 195DEG 13KT 3284 11241
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
HirschSpecial Weather Statement
National Weather Service Phoenix AZ
651 PM MST Sun Sep 11 2022
AZZ538-539-559-120245-
Sonoran Desert Natl Monument AZ-Tonopah Desert AZ-Gila Bend AZ-
651 PM MST Sun Sep 11 2022
...A strong thunderstorm will impact portions of Maricopa County
through 745 PM MST...
At 650 PM MST, Doppler radar was tracking a strong thunderstorm 9
miles south of Bosque, or 10 miles southeast of Gila Bend, moving
northwest at 20 mph.
HAZARD...Winds in excess of 40 mph and half inch 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...
Gila Bend, Gila Bend Auxiliary Field and Bosque.
This includes the following highways...
AZ Interstate 8 between mile markers 109 and 135.
AZ Route 238 between mile markers 1 and 11.
AZ Route 85 between mile markers 1 and 8, and between mile markers
119 and 126.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
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 3280 11236 3268 11264 3298 11290 3305 11255
TIME...MOT...LOC 0150Z 144DEG 16KT 3284 11256
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
HirschSpecial Weather Statement
National Weather Service Phoenix AZ
716 PM MST Sun Sep 11 2022
AZZ553-554-559-120315-
Sonoran Desert Natl Monument AZ-Northwest Pinal County AZ-
West Pinal County AZ-
716 PM MST Sun Sep 11 2022
...A strong thunderstorm will impact portions of Maricopa and Pinal
Counties through 815 PM MST...
At 716 PM MST, Doppler radar was tracking a strong thunderstorm 8
miles west of Chui-Chu, or 13 miles southwest of Casa Grande, moving
north at 20 mph.
HAZARD...Wind gusts up to 50 mph and half inch 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...
Casa Grande, Arizona City, Arizola, Toltec, Stanfield and East
Chui-Chu.
This includes the following highways...
AZ Interstate 10 between mile markers 187 and 204.
AZ Interstate 8 between mile markers 145 and 178.
AZ Route 347 between mile markers 161 and 168.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
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 3267 11236 3298 11216 3301 11187 3297 11160
3284 11153 3273 11167 3273 11174 3280 11178
3276 11205 3272 11207 3272 11214 3268 11215
3268 11220 3259 11221
TIME...MOT...LOC 0216Z 170DEG 19KT 3279 11193
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH
HirschThe Phoenix radar (KIWA), 52 km away, was scanning. The volume nearest the first event began at 02:42 UTC.
13 thunderstorm wind, 6 flash flood, 3 dust storm. Local standard time, as filed.
Visibility of less than 1/4 mile reported along I-8 near Stanfield in blowing dust from thunderstorm outflow. No accidents or injuries were reported.
A local utility company reported 4 power poles were downed in a couple locations north of Stanfield. Winds were estimated at around 60 mph. Timing estimated from radar. No injuries were reported.
The AK-Chin Regional Airport, located northwest of Casa Grande, measured a wind gust of 58 mph.
A local utility company reported 2 downed power poles in 2 locations east of Maricopa. Winds were estimated around 60 mph. Timing estimated from radar. No injuries were reported.
Chandler Municipal Airport measured a wind gust of 60 mph.
Visibility of less than 1/4 mile reported along East Ray Road in the Ahwatukee Foothills in blowing dust from thunderstorm outflow. No accidents or injuries were reported.
Visibility of less than 1/4 mile reported in the intersection of Baseline Road and Rural Road in Tempe in blowing dust from thunderstorm outflow. No accidents or injuries were reported.
Trained spotter measured a 60 mph gust along South Halsted Drive in Sun Lakes.
The City of Queen Creek posted on social media saying to avoid the area of Barnes Parkway and 212th Street due to a tree blown down across the road. Time and wind speed estimated from radar.
Phoenix Sky Harbor Airport ASOS measured a wind gust of 86 mph. This wind gust speed was investigated further as it was considered suspect, however NWS meteorologists determined there was not enough evidence to disprove this measurement. Centerfield winds, a 30 meter wind sensor located just over half a mile north of the ASOS, measured a 76 mph wind gust around the same time as the ASOS. The City of Phoenix Aviation Department shared a report with images that mentioned/showed more than a dozen downed trees, damage to some fencing, cargo containers that were damaged after nearly being blown into a building, at least one downed light pole, and a baggage cart that was blown into and damaged a blast fence. There was also damage to the 24th Street Sky Train station with some broken glass windows at one of the entrances and a small section of outer side paneling that was peeled off. Sky Harbor Airport was in a Ground Stop from 2125MST to 2154MST. No injuries were reported.
The Phoenix-Mesa Gateway Airport measured a wind gust of 75 mph.
Social media photo shows a sheet metal car port, that was torn off of a home, wrapped around a tree near Ironwood Drive and Superstition Boulevard. Timing and wind speed estimated based on radar.
A large uprooted tree fell onto a couple of cars along South Ellsworth Road between East Southern Avenue and East Broadway Road in East Mesa. There were also reports of many damaged or destroyed sheet metal car ports in the area. A small metal shed was also thrown and destroyed. Winds were estimated at around 70 mph. Timing estimated from radar. No injuries were reported.
Social media pictures showed multiple large tree downed across East Mesa, including one tree falling onto a house. Winds were estimated at around 70 mph. Timing estimated from radar. No injuries were reported.
The Mesa Falcon Field Airport measured a wind gust of 58 mph.
Social media picture showed large tree uprooted against a 3 three story apartment complex in the area of North 16th street and Camelback Road. Winds were estimated at around 70 mph. Timing estimated from radar. No injuries were reported.
The City of Queen Creek posted on social media at 2140MST saying Rittenhouse Road near Ocotillo Road was closed due to flooding. Timing of impacts based around radar. No damages or injuries were reported.
Signal Butte Road between East Germann Road and East Barnes Parkway as well as Germann Road at South Crismon Road were closed due flooding. Timing estimated from radar. No damages or injuries were reported.
The Flood Control District of Maricopa County Gauge along East Fork Cave Creek Wash near North 7th Avenue in Phoenix indicated water levels rising above alarm stage at 2232 MST, with the flow peaking 3.77 feet (1557 cfs) at 2259 MST, and not going below alarm stage until 2359 MST. This likely made North 7th Avenue impassable. No damages or injuries were reported.
Maricopa County Department of Transportation reported that Eagle Eye Road was closed between Aguila Road and Mile Post 0 due to flooding. Timing and location of impacts was adjusted based on radar. There were no reports of damage.
Photos from the La Paz County Public Works showed parts of Alamo Road washed out due to extensive flooding from overflowing washes that intersect the road. Timing estimated from radar. No injuries were reported.
SR-72 at Milepost 25 near Bouse was impassable due to wash flowing over the roadway. Timing estimated from radar. No damages or 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, September 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: 1056485, 1056495, 1056470, 1058651, 1056471, 1056472, 1056473, 1056486, 1057817, 1056476, 1056477, 1057816, 1056483, 1056484, 1056478, 1056482, 1057819, 1056490, 1056509, 1057818, 1056530, 1056521.