Moisture continued to flow northward across northern Arizona as the weakening remnants of Kay were post-tropical and located southwest of San Diego. The low level moisture |brought showers and thunderstorms to the area.
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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.
Moisture continued to flow northward across northern Arizona as the weakening remnants of Kay were post-tropical and located southwest of San Diego. The low level moisture |brought showers and thunderstorms to 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 Sep 10, 9:08 AM MST, 4 hours earlier.
Area Forecast Discussion National Weather Service Flagstaff AZ 908 AM MST Sat Sep 10 2022 .SYNOPSIS...Expect cooler temperatures, with scattered to numerous showers and thunderstorms through Tuesday. Conditions then gradually drying out by the middle to latter parts of next week. && .UPDATE...Scattered showers and a few thunderstorms continue this morning mostly across Coconino and Yavapai counties. The more persistent area has been a line extending from Grand Canyon east/southeast toward Kykotsmovi. This is still in response to far reaching outer band activity associated with the decaying remnants of Kay. Forecast models this afternoon show an area of mid level vorticity acting as a focus for shower/storm development, particularly from I-40 northward. Enough of the hi-resolution models show support for this today that we have updated the forecast to increase precipitation chances in these areas. Overall, storm coverage should favor areas along the Mogollon Rim and Coconino Plateau northward. Localized heavy rain and flash flooding remain the primary concern today. Outside of storm activity, a mostly cloudy and cooler day is in store. && .PREV DISCUSSION /251 AM MST/...Moisture continues to flow northward into the region as the weakening remnants of Kay are now post-tropical and located southwest of San Diego. The low level remnants are forecast to move slowly west and then south over the next couple days, while the mid level moisture and decaying circulation will eventually move northeastward across Arizona Monday into Tuesday. For this afternoon - a round of showers and thunderstorms is forecast by most hi-res guidance to develop along the Mogollon Rim west and north through Coconino County. Thinning cloud cover later this morning should allow for better surface heating and instability in this region. This includes the Flagstaff area and the area fire scars where there will be a risk of flash flooding today. Storm activity should diminish overnight. For Sunday, expecting less coverage of storms, though scattered activity is still anticipated. Monday through Tuesday - the remnant mid-level circulation of Kay is forecast to get entrained into the general westerly flow and move across Arizona, as a trough moves into the Pac NW. Widespread showers and thunderstorms are expected Monday, and possibly Tuesday though there is some uncertainty later Tuesday concerning how quickly the better moisture and lift with the trough linger. A few stronger storms are possible during this time, with a marginal flash flood threat. Storms are forecast to move toward the northeast at a decent speed (15-25 mph) and this may keep the overall flooding threat down. Wednesday through Friday - a chance of showers and storms lingers Wednesday though coverage should be decreased. By Thursday and Friday, drier westerly flow with gradually warmer temperatures is forecast. && .AVIATION...For the 18Z TAF package...Brief MVFR or lower visibility conditions are likely in and around thunderstorm activity for this TAF period. Gusty and erratic winds could also be associated in and around storms. Scattered SHRA/TSRA with more widespread storms west of a KGCN-KFLG-KPAN line will continue through at least 02Z. VFR conditions will prevail outside of storm development, with primarily light winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered showers and thunderstorms expected today with more widespread activity west of the I-17 corridor and north of I-40. Gusty and erratic winds along with heavy rainfall will be possible near storms. The coverage of showers and storms is forecast to be lower on Sunday. Temperatures will remain on the cooler side Saturday and Sunday too. Monday through Wednesday...Shower and thunderstorm chances will continue through early next week, along with cooler conditions persisting. Southerly afternoon winds will generally remain light. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...MCT/JJ AVIATION...Swenson FIRE WEATHER...Swenson For Northern Arizona weather information visit weather.gov/flagstaff
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1125 AM MST SAT SEP 10 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1045 AM FLASH FLOOD SUPAI 36.22N 112.69W
09/10/2022 COCONINO AZ OTHER FEDERAL
USGS STREAM GAUGE REPORTED A 1.83 FT. RISE
AT 10:45 AM MST.
&&
PTSSpecial Weather Statement
National Weather Service Flagstaff AZ
1127 AM MST Sat Sep 10 2022
AZZ015-101900-
Western Mogollon Rim-
1127 AM MST Sat Sep 10 2022
...Strong thunderstorms will impact portions of the Flagstaff Metro
Area in Coconino County through NOON MST...
At 1126 AM MST, Doppler radar was tracking strong thunderstorms over
Flagstaff, moving northwest at 20 mph.
HAZARD...Winds in excess of 30 mph and heavy rainfall.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Localized flooding is possible.
Locations impacted include...
Flagstaff, Cosnino, Fort Valley, Flagstaff Mall, Walnut Canyon
National Monument, Downtown Flagstaff, Hutchison Acres, Walnut Canyon
Visitors Center, Little Elden Spring Horse Camp, Canyon Vista
Campground and Lower Lake Mary.
This includes the following highways...
Route 66 between mile markers 192 and 204.
Interstate 40 between mile markers 192 and 208.
U.S. Highway 89 between mile markers 419 and 423.
Highway 180 between mile markers 217 and 224.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 3521 11145 3514 11144 3509 11155 3523 11179
3536 11165
TIME...MOT...LOC 1826Z 121DEG 18KT 3520 11160
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH
EFLThe Flagstaff radar (KFSX), 95 km away, was scanning. The volume nearest the first event began at 20:06 UTC.
4 flash flood. Local standard time, as filed.
Heavy rain over the Tunnel and Pipeline fire scar caused flash flooding across Highway 89. The highway closed in both directions at mile marker 430 from 108 PM until 440 PM.
The river gauge at the Village of Supai showed a 1.83 foot rise at 1045 AM. The stream gauge at the confluence with the Colorado River (about 10 miles down stream from the Village of Supai) had a 5.5 foot rise in about 45 minutes at 1145 AM. The crest was at 12.57 feet with a flow of 1735 CFS. Base flow is at about 7 feet with a flow of 70 CFS.
A river gauge on the Paria River near the Colorado River showed a 1.83 foot rise at 545 PM MST.
Flash flooding was reported about 10 miles north of Joseph City at the intersection of Blairs Spring Wash and North Porter Road. The dirt road was washed out by the flooding and a vehicle got stuck.
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: 1055621, 1055619, 1055620, 1055622.