An intense area of low pressure plunged into Southern California, bringing high winds along with some wet and snowy weather.
Every event with a place to put it; 7 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 intense area of low pressure plunged into Southern California, bringing high winds along with some wet and snowy weather.
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 14, 8:45 PM PST, 3 hours 15 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
945 PM PDT Sun Mar 14 2021
.SYNOPSIS...
A fast-moving storm will bring windy and colder weather on Monday.
Showers will develop ahead of a cold front that will sweep across
Southern California starting in the morning, with snow lingering
in the mountains through the evening. The wintry storm system
will move east Monday night, allowing winds to decrease and a slow
warming trend to begin on Tuesday. It will be dry and warmer for
the balance of the work week. Another upper-level trough will
arrive next weekend with cooler, breezy, and potentially more wet
weather.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.EVENING UPDATE...
Clouds continue to fill the coastal basin this evening as the
marine layer deepens overnight. Winds continue to be gusty out of
the west with some locations in the passes gusting over 40 MPH.
The incoming storm system is to our north, where prefrontal
showers are starting to enter San Luis Obispo County. The latest
hi-res model guidance indicates showers coming into OC first a
bit after sunrise, and pushing southward through the region
through the morning and arriving in San Diego by early afternoon.
Winter Weather Advisory timing pushed up a bit for the morning, as
models are indicating onset of precip will be slightly earlier.
.PREVIOUS DISCUSSION (128 PM Sunday)...
* Another round of Winter for the mountains on Monday/Monday night
* Strong/possibly damaging winds over the mountains/deserts Monday
* Gales over the coastal waters and windy along the Coast
* Below normal temperatures Monday, warming through the week
The onshore sfc pressure gradient will increase through this
evening, helping to boost wind speeds back into the 30 MPH with
gusts 50 to locally 60 MPH overnight on the ridges and through and
below passes. Our windiest pass/mtn areas at 1 PM PDT already had
west winds 30-35 MPH with gusts 40-50 MPH. A Wind Advisory has
been posted for the passes and mountains of Riverside and San
Diego County for later this afternoon and tonight ahead of the
strongest winds on Monday.
Low pressure is dropping south, off the PacNW Coast this afternoon
and will slide SE across CA on Monday, reaching Las Vegas late Mon
evening. Moisture being drawn inland ahead of this system (PW 0.75+
inch) will interact with a cold front to produce some, mostly light
rain across the coastal basin, and heavier upslope rain and mountain
snow far inland. Strong westerly winds will top the mountains and
dip into the deserts, and gale force winds are expected over our
coastal waters as this system passes. A High Wind Warning is in
effect, and a Winter Weather Advisory has been issued for snow,
wind, cold, and difficult travel conditions over our mountains on
Monday into Monday night. It will be another chilly day with daytime
highs from 12-20F below average.
Rainfall amounts overall will be light, ranging from around one-
tenth of an inch near the coast to one-half inch or so on the lower
coastal slopes. Local heavier amounts are possible inland. The snow
level will begin from 4500-5000 FT Wednesday morning, and quickly
fall to around 3500 FT by evening. Snowfall of from a coating near
3500 FT, to 4-7 inches above 4500 FT is possible. The combination of
very strong winds with gusts 50-70 MPH, snowfall, and slippery
roads, will make travel hazardous from late Monday morning through
Monday night. These conditions will likely impact travel along the I-
8 and through the Cajon Pass.
The storm moves east Mon night and Tuesday, allowing winds to drop
off and a gradual warm-up to begin as a weak ridge builds aloft.
This will bring a period of quiet and warmer weather just ahead of
the official start of Spring. Another trough will be slipping south
along the Coast by next weekend and could bring us more chilly
weather and precipitation, but there is no consensus between
ensemble members of the GFS or the ECMWF, suggesting a lot of
uncertainty exists in timing and track of this next system. In the
meantime, daytime temperatures should be back to average by
Thursday, and even a little warmer on Friday.
&&
.AVIATION...
150400Z...Coast/Valleys/Mountains...Widespread cloud bases 1500-2500
feet MSL this evening, will gradually rise throughout the night to
3000-4000 feet MSL by 15Z Monday. SHRA to move into northern areas
after 14Z, spreading into San Diego County after 17Z. Winds will
become strong all areas with sfc gusts 35-40 kts at times throughout
the day Monday...with the highest wind gusts through the mountain
passes and along the mountaintops where gusts to 75 kts will be
likely. Strong up/downdrafts will also be likely, especially over
the mountains.
Deserts...Cloud bases around 5000 FT MSL will develop after 12Z
Monday, with isolated SHRA after 17Z. Strong W-NW winds through
Monday evening with sfc gusts 40-50 kts at times between 18Z Monday
to 06Z Tuesday. LLWS and strong up/downdrafts will occur over and
east of the mtns during this time. Mountain Rotors with strong
surfacing winds possible at KPSP and KTRM Monday afternoon and
evening, when gusts 50 kts or higher could occur. In addition
reduced visibility, possibly to near-zero at times, could occur in
the desert due to blowing dust and sand.
&&
.MARINE...
Northwest winds will increase Monday morning across the coastal
waters, with gusts 35 knots, and isolated gusts as high as 40 kts
possible, and combined seas of 8 to 12 feet. A Gale Warning is in
effect from Monday morning through late Monday night. No additional
hazardous marine weather is expected Tuesday through Friday.
&&
.BEACHES...
An increased northwest swell will bring elevated surf and a high rip
current risk to the beaches Monday afternoon through Tuesday. In
Orange County, surf will be 3 to 6 feet. In San Diego County, surf
will be 4 to 7 feet. Surf will gradually diminish Tuesday afternoon
and evening.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning from 8 AM Monday to 2 AM PDT Tuesday for Apple
and Lucerne Valleys-Coachella Valley-Riverside County
Mountains-San Bernardino County Mountains-San Diego County
Deserts-San Diego County Mountains-San Gorgonio Pass Near
Banning.
Winter Weather Advisory from 8 AM Monday to 3 AM PDT Tuesday for
Riverside County Mountains-San Bernardino County Mountains-
San Diego County Mountains.
Wind Advisory until 8 AM PDT Monday for Riverside County
Mountains-San Diego County Mountains-San Gorgonio Pass Near
Banning.
Wind Advisory from 11 AM to 8 PM PDT Monday for Orange County
Coastal Areas-Orange County Inland Areas-San Diego County
Coastal Areas.
PZ...Gale Warning from 11 AM Monday to 5 AM PDT Tuesday 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.
&&
EVENING UPDATE...APR
PUBLIC...10
AVIATION/MARINE/BEACHES...BrothertonThe national radar mosaic for the moment the first event began.
5 high wind, 1 dust storm, 1 heavy snow. Local standard time, as filed.
The desert slopes of the San Bernardino Mountains reported gusty winds. Burns Canyon RAWS gusted to 81 MPH.
The desert areas near the San Bernardino Mountains reported gusty winds. Burns Canyon RAWS gusted to 81 MPH. Cushenbury Springs reported a gust of 81 MPH.
Gusty winds occurred across the area. Snowpeak Canyon Road gusted to 61 MPH.
Gusty winds occurred across the area. Mt. Laguna gusted to 69 MPH.
Gusty winds occurred in the area, especially near Borrego Springs with a gust of 61 MPH.
Gusty winds occurred across the region with Coachella gusting to 56 MPH. This prompted areas of blowing dust and reduced visibility for areas north of Palm Springs, as well as Highway 86 in the southern part of the valley and western shores of the Salton Sea.
The area received up to 6 inches of snow, reported via local ski resorts.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, March 2021
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: 948562, 948563, 948564, 948565, 948566, 948567, 948568.