An active monsoon season continued to impact Southern California, with multiple days of thunderstorms reported across the mountains from August 22-26. The main hazards were heavy rain and minor debris flows, as well as gusty winds from thunderstorms.
Every event with a place to put it; 2 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 SGX wrote it up.
An active monsoon season continued to impact Southern California, with multiple days of thunderstorms reported across the mountains from August 22-26. The main hazards were heavy rain and minor debris flows, as well as gusty winds from thunderstorms.
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 San Diego, CA wrote its last area forecast discussion before the first event at Aug 23, 1:00 PM PST, 1 hour 30 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
200 PM PDT Tue Aug 23 2022
.SYNOPSIS...
Monsoonal moisture will continue to increase Wednesday into
Thursday, leading to active days of thunderstorms over the
mountains with a lesser risk over the deserts. Dry air will move
in on Friday and fully into the region this weekend ahead of an
upper trough, leading to dry conditions. Temperatures will be
highest today with gradual cooling through the weekend before
heating up next week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
KEY POINTS:
* Active monsoon thunderstorm days Wednesday and Thursday
* Isolated thunderstorms possible Friday, then dry this weekend
* Slight cooling through the weekend, then heating up next week
Monsoonal moisture, the core of which is currently residing over
SE California/SW Arizona with PW up to 1.8 inches per SPC
mesoanalysis, will move northwest and overspread our service area
through Wednesday. The monsoonal moisture will remain entrenched
over our region on Thursday before shifting east on Friday. This
progression will lead to active thunderstorm days for the
mountains both Wednesday and Thursday with a lesser risk for the
deserts. Areas west of the mountains look to remain dry.
The flash flood concern exists Wednesday and Thursday afternoon,
but confidence is not quite high enough for a Flood Watch at this
time. Moisture levels are slightly lower than our previous active
monsoon days. We will take a look this evening and overnight to
see if a watch might be needed. The greatest flash flood risk will
be over the mountains with a lower risk over the deserts.
There is some indication on hi-res models, particularly our local
WRF model, of a possible MCS moving towards the Coachella Valley
and the San Diego County deserts while weakening late Wednesday
night. Have added slight chance of tstorms for the lower deserts
Wednesday night to account for this potential. Some HRRR runs
even show light echoes making it west of the mountains with a few
hundredths of an inch. This will be something to monitor for
possible blowing dust over the lower deserts arriving late
Wednesday night on thunderstorm outflows.
The inland heat is peaking today, then we will see gradual
cooling. First in part due to the monsoonal moisture and then due
to better onshore flow as an upper trough digs off the U.S. West
Coast by the weekend. This will spread cooling inland and humidity
will lower a nudge as well.
GFS and EC ensembles are pointing to a building ridge mid next
week centered over SoCal. This scenario would bring building heat
to the region as we close out August and move into September.
Something to monitor. Differences are seen in the ensemble members
next week in how much monsoonal moisture will return next week.
The mean shows a slow, gradual increase while individual members
vary from keeping moisture rather low to some members more
aggressive on moisture return. For now, next week looks to feature
building heat with a slight chance of thunderstorms returning as
September arrives.
&&
.AVIATION...
232015Z...Coast/Valleys...Low clouds with bases near 1000 FT MSL
will continue across beach locations this afternoon. Low clouds will
push back inland after 02z Wed and spread up to 20 SM inland, with
bases 700-1000 FT MSL. Scatter out 17-19z Wed, though patchy BKN
will continue into the afternoon across the immediate coast.
Mountains/Deserts...Mostly clear skies through tonight. Iso TSRA
will be possible in the mtns through 01z Wed with bases near 10,000
FT and tops to 30,000 FT MSL. Gusty and erratic winds, frequent
lightning and heavy downpours will be possible vcty TSRA.
&&
.MARINE...
No hazardous marine weather is expected through Sunday.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Excessive Heat Warning until 10 PM PDT this evening for Apple
and Lucerne Valleys.
PZ...None.
&&
PUBLIC...Gregoria
AVIATION/MARINE...MoedeThe Santa Ana Mts radar (KSOX), 71 km away, was scanning. The volume nearest the first event began at 22:29 UTC.
12 heavy rain, 2 strong wind, 1 debris flow, 1 thunderstorm wind, 1 flash flood, 1 flood. Local standard time, as filed.
Mesonet HADS Station FFPC1 1.5 miles west of Forest Falls measured 0.53 inches of rain in 1 hour.
CHP reported rocks in the middle of lanes along Highway 38 just north of the Forest Falls junction.
Mesonet station ALNC1 near Idyllwild-Pine Cove measured 0.87 inch of rain.
Mesonet station at Palomar Mountain Lookout.
Mesonet station SE375 Keen Ridge (SCE375) reported a thunderstorm wind gust of 55 mph. Temperature fell from 80 degrees to 68 degrees.
Mesonet station EW3043 Big Bear City measured 1 inch of rain in 90 minutes.
Heavy rain on I-8 near the Crestwood Road on-ramp. Multiple vehicles parked on the right hand side due to the torrential rain, hail, and poor visibility.
Mesonet station YUCC1 Little San Gorgonio Peak at Yucaipa Ridge at 9000 feet measured 0.47 inches of rain in 15 minutes.
Mesonet station CWDSD Crestwood (SDGE) reported a thunderstorm wind gust of 52 mph.
Minor flooding and small hail shared in photos from the Cahuilla Reservation off of Highway 371.
Mesonet station NZAC1 Anza measured 0.76 inch of rain in 1 hour.
Lake Cuyamaca spotter received 0.75 inches of rain in 45 minutes.
Mesonet station KWYC1 Kenworthy along Highway 74 measured 1.04 inches of rain in 1 hour.
Mesonet station VCNC1 2.8mi north of Julian at Volcan Mountain measured 1.01 inches of rain in 1 hour.
Mesonet station PAMC1 Palomar Mountain RAWS measured 0.88 inch of rain in 1 hour. Temperature dropped from 87 to 72F.
Mesonet station FW0019 Lake Cuyamaca measured 0.49 inch of rain in 45 minutes.
Rainfall of 0.61 inches was measured between 12:45 PM and 2 PM.
Toro Peak HPWREN site measured 1.11 inches of rain in 1 hour.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, 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: 1045776, 1045790, 1045780, 1045794, 1047252, 1045786, 1045773, 1045781, 1047251, 1045774, 1045782, 1045777, 1045778, 1045779, 1045784, 1045785, 1045789, 1045788.