Another cold upper level system led to widespread precipitation and strong winds in Southern California on March 21st through the 23rd.
Every event with a place to put it. 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.
Another cold upper level system led to widespread precipitation and strong winds in Southern California on March 21st through the 23rd.
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 Mar 21, 3:40 AM PST, 1 hour 20 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
440 AM PDT Tue Mar 21 2023
.SYNOPSIS...
A rapidly intensifying low pressure system off the California
coast will move inland and bring much cooler weather with
widespread moderate to locally heavy precipitation this morning,
widespread showers this evening, with occasional showers
continuing through Wednesday. Strong and potentially damaging
winds will develop with a passing cold front through midday with
stronger and gusty southwest to west winds continuing at times
into Wednesday. Mostly dry and breezy at times for Thursday
through the weekend with continued below average temperatures.
Another low pressure system from the northwest could bring more
precipitation some time around the early to middle part of next
week.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (Today through Thursday)...
Early this morning, a low pressure system is rapidly intensifying
off the central California coast. This low pressure system will
tap moisture from an atmospheric river to bring widespread
moderate to locally heavy rainfall this morning with the moisture
transport from the atmospheric river peaking late this morning,
then decreasing.
A second band of more widespread showers will move through the
area from the northwest during the late afternoon into the
evening. There will be additional showers through Wednesday,
ending from the northwest Wednesday night. There is also a slight
chance of thunderstorms for tonight and Wednesday morning.
The snow level will be rise to near 7000 to 7500 feet this
morning, then fall to around 5000 to 5500 feet for late this
afternoon and 4000 feet for late tonight. The snow level will then
fluctuate around 4500 feet for Wednesday afternoon and evening.
Snowfall will be measured in feet above 6000 feet with 4 feet or
more possible on the higher peaks above 7500 feet.
South winds will rapidly strengthen early this morning ahead of
the cold front. There could be isolated gusts to near 60 mph near
the coast this morning. The winds will become southwesterly for
the afternoon and evening. The strongest winds today are expected
along the lower desert slopes of the San Bernardino County
mountains with isolated gusts to near 100 mph possible during the
late morning and early afternoon.
Areas west of the mountains are expected to have the strongest
winds today. Along the desert slopes of the mountains in Riverside
and San Diego Counties, the strongest winds could be on Wednesday.
Wednesday is expected to be the coolest day. Drying for Thursday
with high temperatures around 5 degrees warmer than Wednesday.
&&
.LONG TERM (Friday through Monday)...
Continued cool and occasionally breezy for Friday through the
weekend with below average temperatures. The weather is expected
to be mostly dry. It is not out of the question that a low
pressure system over the Great Basin could bring a few light
showers to the mountains on Sunday as shown by a smaller subset of
ensemble members. Another low pressure from the northwest could
bring more precipitation some time during the early to middle part
of next week.
&&
.AVIATION...
210930Z...Coast/Valleys/Mountains...BKN-OVC clouds with bases mostly
2000-3500 ft MSL, with RA and mountain SN increasing this morning.
Bases lowering to 500-1500 ft MSL and areas of VIS 1-3SM. After 18Z,
decreasing RA/SN will occur with bases rising to 1000-3000 ft MSL.
Widespread terrain obscurations will prevail today. South winds will
increase this morning with surface gusts 25-45 knots coast/valleys
and 35-65 knots mountains, decreasing somewhat after 19Z. -SHRA and
-SHSN will continue through tonight with some cloud breaks and bases
varying between 1500-3000 feet MSL and vis mostly P6SM.
Deserts...South to southwest winds on desert mountain slopes and
locally into the deserts, with peak gusts 40-55 kt this morning.
Moderate up/downdrafts and LLWS expected over/northeast of the
mountains. RA will occur in the deserts through 20Z with BKN-OVC
bases 3000-5000 ft MSL. More scattered -SHRA and clouds lifting this
afternoon above 5000 ft MSL.
&&
.MARINE...
A powerful storm will arrive today, bringing southerly gales and
hazardous seas into Wednesday. There is a chance of thunderstorms
and waterspouts tonight and Wednesday morning. Check the Gale
Warning for details and stay tuned for any special marine weather
bulletins that may be issued. Winds and seas will gradually subside
late Wednesday. Northwest winds will increase again for Thursday
through Saturday in the outer waters, which would bring more
hazardous winds and choppy conditions.
&&
.BEACHES...
A storm will bring large swell and surf tonight through Thursday.
Breakers will range from 4 to 8 feet, with sets up to 12 feet in
southern San Diego County. This will produce hazardous swimming
conditions and local beach erosion. Swell and surf should subside
Thursday. Check the High surf advisory for details.
&&
.HYDROLOGY...
A rapidly intensifying low pressure system off the California
coast will tap moisture from an atmospheric river to bring
widespread moderate to locally heavy rainfall this morning.
Moisture transport from this atmospheric river is expected to peak
during the late morning, with a secondary lower peak during the
late afternoon or early evening.
A second band of more widespread showers will move through the
area from the northwest during the late afternoon into the
evening. There will be additional showers through Wednesday,
ending from the northwest Wednesday night. There is also a slight
chance of thunderstorms for tonight and Wednesday morning.
The snow level will be rise to near 7000 to 7500 feet this
morning, then fall to around 5000 to 5500 feet for late this
afternoon and 4000 feet for late tonight. The snow level will then
fluctuate around 4500 feet for Wednesday afternoon and evening.
Rainfall and liquid equivalent above the snow level is expected to
range from around 1.5 to 2 inches near the coast to 4 to 7 inches
in the mountains with locally greater amounts. One-half to one inch
is expected for the high desert and one-tenth to one-half inch in
the lower deserts.
The San Diego River and Santa Margarita River are both forecast to
at least rise above monitor stage this morning and could crest
close to minor flood stage by late this evening. Expect areas of
small stream and urban flooding to develop with soils already
nearly saturated.
With all of the rainfall that will be occurring below the snow
level, expect significant runoff, which could contribute to local
flooding issues especially at low-water crossings and in poorly
drained urban areas. Other areas of concern will be the
Whitewater River and Coachella Canal in the Coachella Valley, as
well as the Tijuana River watershed.
&&
.SKYWARN...
Skywarn activation is requested through this evening and possibly
into Wednesday.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Flood Watch through Wednesday evening for San Diego County
Coastal Areas-San Diego County Mountains-San Diego County
Valleys.
High Wind Warning until midnight PDT tonight for Orange County
Coastal Areas-Orange County Inland Areas-San Diego County
Coastal Areas-Santa Ana Mountains and Foothills.
High Surf Advisory from 2 AM Wednesday to 9 PM PDT Thursday for
San Diego County Coastal Areas.
Flood Watch through Wednesday afternoon for Orange County
Coastal Areas-Orange County Inland Areas-Riverside County
Mountains-San Bernardino County Mountains-San Bernardino
and Riverside County Valleys-The Inland Empire-San Gorgonio
Pass Near Banning-Santa Ana Mountains and Foothills.
Wind Advisory until 10 PM PDT this evening for San Bernardino
and Riverside County Valleys-The Inland Empire.
Wind Advisory until midnight PDT tonight for San Diego County
Valleys.
Winter Storm Warning until 6 PM PDT Wednesday for Riverside
County Mountains-San Bernardino County Mountains.
High Wind Warning from 10 AM this morning to 6 PM PDT this
evening for San Diego County Mountains.
Winter Weather Advisory from 6 PM this evening to 10 PM PDT
Wednesday for San Diego County Mountains.
High Wind Warning from 10 AM this morning to noon PDT Wednesday
for Apple and Lucerne Valleys-San Diego County Deserts-San
Gorgonio Pass Near Banning.
Wind Advisory from 10 AM this morning to 10 PM PDT this evening
for Coachella Valley.
High Surf Advisory from 2 AM Wednesday to 9 AM PDT Thursday for
Orange County Coastal Areas.
PZ...Gale Warning until 9 AM PDT Wednesday for Coastal Waters from
San Mateo Point to the Mexican Border and out to 30 nm-
Waters from San Mateo Point to the Mexican Border Extending
30 to 60 nm out including San Clemente Island.
&&
PUBLIC/HYDROLOGY...17
AVIATION/MARINE/BEACHES...MMThe Santa Ana Mts radar (KSOX), 52 km away, was scanning. The volume nearest the first event began at 13:00 UTC.
16 flood, 2 thunderstorm wind, 1 flash flood. Local standard time, as filed.
De Luz Road was closed due to flooding. About 0.50-0.70 inch of rain fell in this area in the 12hrs prior.
In the Rainbow area, Huffstatler St was closed from 5th St to 2nd St due to flooding. About 0.50-0.70 inch of rain fell in the 12 hours prior.
In Escondido, Country Club Drive was closed south of Harmony Grove Road due to flooding.
Flooding was reported in Lane 2 at the intersection of SR75 and Attu Avenue. Rainfall of 0.60 inch fell in the previous 6 hours.
The I-8 East on ramp at Texas Street was flooded, with water up to vehicle tires. Rainfall of 0.70 to 0.80 inches fell in the previous 6 hours.
Flooding on Vesper Road lead to multiple vehicle spinouts. About 0.90 to 1.10 inches of rain fell in this area in the previous 12 hours.
The off-ramp on I-5 North at La Jolla Village Drive was flooded. About 0.65 inch of rain fell in the previous 6 hours.
In Murrieta, the parking lot in front of the local Sam's Club was flooded with water about 1 foot deep.
A large tree was downed near Weidners Garden.
A swiftwater rescue was needed near Cajon Boulevard and Swarthout Canyon Road after a vehicle tried to cross high water and got swept away in the current. The vehicle was swept approximately 100 yards down the river and was not recoverable.
Roads near the intersection of Anza Road and De Portola Road were shut down due to flowing water and a mud slide. A jeep vehicle required a rescue after it was stuck in 2 feet of flowing water and mud. About 1.4 inches of rain fell in this area in the previous 12 hours, with 1 inch falling in 6 hours.
A large tree was downed, resulting in a power outage.
The eastbound right-hand lane of Murrieta Hot Springs Road was flooded by a 3-foot waterfall from Warm Springs Creek. About 1.4 inches of rain fell in this area in the previous 12 hours.
Low-lying portions of Barona Road and Wildcat Canyon Road were flooded. Total rainfall of 1.6 inches occurred.
About 2 inches of rain fell at Palomar Mountain nearby, leading to the San Luis Rey River flowing over Cole Grade Road with water 1 to 2 feet deep.
A trained spotter reported fast-moving water over Via Montezuma at Murrieta Creek, prompting a road closure.
A trained spotter in Temecula shared a photo of a flooded road crossing near Murrieta Creek.
About 0.43 inch of rain fell in one hour between 7 and 8 PM, leading to flooding on Ocean View Blvd.
SR94 near College Grove Drive had all lanes flooded with standing water. About 0.35 inch of rain fell in 90 minutes prior to this report, with 1.27 inches falling in the previous 30 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, March 2023
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: 1086672, 1086673, 1086674, 1086675, 1086676, 1086677, 1086678, 1086679, 1086688, 1086680, 1086681, 1086689, 1086682, 1086683, 1086684, 1086685, 1088837, 1086686, 1086687.