A passing frontal system brought gusty onshore winds, along with areas of dense fog February 3rd through 7th.
Every event with a place to put it; 4 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 passing frontal system brought gusty onshore winds, along with areas of dense fog February 3rd through 7th.
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 3, 4:37 AM PST, 1 hour 23 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
437 AM PST Wed Feb 3 2021
.SYNOPSIS...
A low pressure system moving southeastward through the Great Basin
today will bring cooling, a return of the marine layer with morning
coastal low clouds and locally dense fog, and gusty west winds
for the mountains and deserts this afternoon and evening. The flow
will turn offshore on Thursday with warming west of the
mountains, cooling in the deserts, and gusty northeast winds along
and below the coastal slopes of the mountains. Friday and Saturday
will warm with northeast winds weakening and becoming more
localized. For Sunday through Tuesday, there will be a return of
onshore flow spreading slow cooling inland. There will also be
periods of high clouds with night and morning coastal low clouds
and fog.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (Today through Friday)...
A low pressure system over the Pacific Northwest will move
through the Great Basin today strengthening the onshore flow over
southern California. This will spread cooling inland with gusty
west winds in the mountains and deserts this afternoon and
evening. Coastal low clouds and fog have returned and spread
locally inland near the coast. Aircraft soundings Tuesday evening
showed the marine layer was around 1200 feet deep in southern San
Diego County and around 600 to 800 feet deep in southern Los
Angeles County. Low clouds and locally dense fog will spread
inland in San Diego County to the mesas and western valleys and
into coastal and some inland areas of Orange County.
The lower level flow will turn offshore for Thursday with gusty
northeast winds along and below the coastal slopes of the
mountains and below passes and canyons with the stronger gusts
mostly 45 mph or less. High temperatures west of the mountains
will warm while the deserts continue to cool. For Friday,
northeast winds will be weaker and more localized. Warming will
continue for the coast and valleys with greater warming pushing
into the mountains and deserts with high temperatures generally
around 5 degrees above average.
&&
.LONG TERM (Saturday through Tuesday)...
High pressure off the West Coast will continue warming into
Saturday for the lower deserts and inland valleys with the coast
beginning to cool.
For Sunday through Tuesday, high pressure off the West Coast will
weaken and onshore flow will return across southern California.
This will bring a slow cooling trend with periods of high clouds
at times and areas of night and morning coastal low clouds and
fog.
For Wednesday of next week, the cluster with the greatest support,
supported by the deterministic ECMWF, the ensemble means of the
ECMWF, GFS, and Canadian models, and the greatest percentage of
the ensemble members of each of those models have high pressure
aloft along the West Coast. This would result in high temperatures
for Wednesday similar to those of Tuesday, slightly below average
for the coast and valleys and slightly above average for the
mountains and deserts. The deterministic runs of the GFS and
Canadian models have a more zonal pattern with less ensemble
support. This would bring a few degrees of additional cooling for
the coast and valleys.
&&
.AVIATION...
031030Z...Areas of coastal low clouds will continue this morning.
Bases between 400-800 feet MSL with tops to 1200 feet. Vis 0-6SM
where clouds/fog form. Most areas should clear 15Z-17Z. Low clouds
this evening after 04Z will be more dispersed and higher-based,
around 800-1400 feet MSL. Otherwise, SCT clouds at/above 12000 feet
MSL will continue region-wide today and tonight. Some westerly
surface winds 15-25 knots gusts 30-35 knots after 22Z over the
mountains and desert slopes.
&&
.MARINE...
Northwest winds with gusts 20-25 kt are expected this afternoon
through early Thursday over the outer coastal waters. These winds
could cause hazardous boating conditions, and a Small Craft Advisory
is in effect then. No hazardous marine conditions are expected
Thursday through the weekend.
&&
.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 1 PM this afternoon to 3 AM PST
Thursday for Waters from San Mateo point to the Mexican
Border Extending 30 to 60 nm out including San Clemente
Island.
&&
PUBLIC...17
AVIATION/MARINE...MMThe national radar mosaic for the moment the first event began.
2 dense fog, 2 high wind. Local standard time, as filed.
Lifeguards and trained spotters report dense fog, some near 0 miles at times.
Areas recorded wind gusts over 60 MPH at times.
Winds gusted over 60 MPH in some areas.
Lifeguards and trained spotters report dense fog, some near 0 miles at times.
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: 939988, 939986, 939987, 939989.