A potent mid-level shortwave trough passed through Southern California and produced strong onshore flow (west to northwest winds) followed by gusty Santa Ana winds.
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 SGX wrote it up.
A potent mid-level shortwave trough passed through Southern California and produced strong onshore flow (west to northwest winds) followed by gusty Santa Ana winds.
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 Feb 11, 9:09 PM PST, 2 hours 51 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
909 PM PST Thu Feb 11 2021
.SYNOPSIS...
A compact low pressure system will drop southeast across California
tonight and Friday, bringing a chance of showers along and west of
the mountains. Cool, dry weather is on deck for Saturday, but
another passing weather system will rev up strong, westerly winds
across the mountains and deserts late in the day. It will be a
little warmer on Sunday as winds decrease and the clouds part. Fair,
dry, and seasonal weather will prevail much of next week, with
periods of gusty offshore winds.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING
ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN
BERNARDINO COUNTIES...
Marine clouds were thickening and spreading well inland early this
evening as higher clouds sweep southeast across central parts of the
State. Most of the rain reports over the past several hours have
been in the SFO Bay area, but radar shows some weak echoes dropping
SE along the coast south of Pt. Conception. Onshore sfc pressure
gradients are ramping up this evening. Peak westerly winds over the
mts were gusting around 35 MPH.
The latest hires models available still show scattered, light
showers developing along and west of the mountains of SoCal late
tonight through Fri morning. Forecast rainfall amounts are still
very light, but could be enough to wet roads in some areas. Of more
concern will be strong westerly winds that will be developing over
the mts, and some desert areas Saturday afternoon/evening, so
monitor later forecasts for that. No forecast changes this evening.
From previous discussion...
The low pressure system currently off the coast of Oregon is
slated to drop south into SoCal late tonight through Friday,
bringing us cooler temperatures, increased west winds, and chances
for precipitation Friday. Amounts will range from a trace to
0.10" for the coast and valleys (perhaps a little higher in the
San Diego valleys) and up to 0.20-0.30" for the mountains. A
dusting of snow could occur above 6000 feet in the mountains.
Winds will be gusty in the mountains, desert slopes, and deserts
with gusts topping out at 30-40 mph.
For the weekend, another low pressure system is expected to move
over the West, but it continues to trend further inland. With that
inland shift, most models and ensembles now show little to no
precipitation for us with this system. It will bring us another
round of gusty west winds to the mountains, desert slopes and
deserts. These winds look to be stronger than the previous system,
with gusts topping out around 50-60 mph.
Northwest flow will prevail early to mid next week, with overall
minor day-to-day changes in high temperatures. Models and
ensembles are showing another weak low pressure system impact the
West on Tuesday, but is looking to have an inland track at this
time, which would limit our precipitation chances. A period of
gusty north to northeast winds is possible late Tuesday and
Wednesday behind this system.
&&
.AVIATION...
120430Z...Coasts/Valleys/Mountains...areas of low clouds with bases
1200-1700 ft MSL and tops to 2000 ft MSL will spread into the
valleys overnight, pushing into the coastal mountain slopes by
sunrise with tops increasing to near 5000 ft MSL. Higher terrain
becoming obscured by Friday morning. ISO-SCT showers 14Z-20Z Fri
locally reduce vis to 3-5 SM. Clouds gradually becoming SCT to
locally BKN with bases generally above 3000 ft MSL after 19Z.
Desert Mountain Slopes/Deserts...Increasing west winds with sfc
gusts 30-40 kt between about 13-20Z. Isolated gusts near 45 kt
possible below the San Gorgonio Pass. STG-SVR up/downdrafts and
rotors possible over/east of the mountains. Winds gradually
weakening Friday afternoon. Otherwise SCT-BKN clouds AOA 15,000 ft
MSL and unrestricted vis through Friday evening.
&&
.MARINE...
Northwest winds with gusts 20 to 25 kt developing over the outer
coastal waters Friday morning, and a Small Craft Advisory remains in
effect from 10 AM through 7 PM Friday. Even stronger winds with
gusts 25-30 kt and combined seas to 10 feet or more are expected
late Saturday through Sunday, leading to more widespread hazardous
marine conditions.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...Small Craft Advisory from 10 AM to 7 PM PST Friday for Waters
from San Mateo point to the Mexican Border Extending 30 to
60 nm out including San Clemente Island.
&&
PUBLIC...10/Connolly
AVIATION/MARINE...SSThe national radar mosaic for the moment the first event began.
2 high wind, 1 dust storm. Local standard time, as filed.
Gusty west to northwest winds occurred across the region with 82 MPH recorded at the Whitewater RAWS on afternoon of the 13th.
Dust storm report from 5 NNW of Palm Springs. Palm Springs police department reported North Indian Canyon Drive was closed between Garnet and Sunrise Pkwy due to drifting sand on the roadway and near zero visibility. The road reopened around 7 am Sunday the 13th. Palm Springs airport had squall wind gust 52 mph at 3 pm February 13.
Portions of the mountains near Mount Laguna reported gusts over 60 MPH.
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, February 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: 935541, 943104, 936662.