Another inside slider occurred at the end of the month, which produced more cool and windy weather across the mountains and deserts.
Every event with a place to put it; 1 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.
Another inside slider occurred at the end of the month, which produced more cool and windy weather across the mountains and deserts.
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 29, 8:30 PM PST, 3 hours 30 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
930 PM PDT Mon Mar 29 2021
.SYNOPSIS...
Onshore flow will strengthen overnight with gusty westerly winds
develop over the mountains and deserts. Winds will turn northerly
and increase early Tuesday morning over northern areas, then
spread farther south Tuesday night into Wednesday from the
northeast. This will spread very dry and warmer air westward
toward the coast where temperatures will be well above normal.
Gradual cooling will return for coastal areas by Friday, working
inland by the weekend.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
A shallow marine layer will build inland overnight as onshore
flow increases. Gusty westerly winds will blow over the
mts/deserts this evening and could reach around 50 MPH or so
through and below the windier passes before turning northerly late
tonight.
A trough is deepening inland over the Rockies, helping to draw the
onshore flow inland, but as it passes late tonight and Tue morning,
north winds will turn NE and become moderately strong and gusty at
times Tue/Wed. This will create Santa Ana conditions with very low
relative humidity and well above average temperatures west of the
mountains. Warmest days west of the mountains will be Wed/Thu,
transitioning inland for Thu/Fri. A Wind advisory has been posted
for portions of the San Bernardino Mts, Santa Ana Mts, and Inland
Empire. The main threat area will be through and below the Cajon
Pass.
Once our midweek Santa Ana abates, a rather quiet weather pattern
develops late in the week through the weekend as onshore flow
gradually increases and helps to build the marine layer inland with
nocturnal low clouds and fog, and cooler days. A passing trough
early next week looks to carry any precipitation north of SoCal, but
later next week, ensemble solutions suggest another, potential for
some precipitation here.
&&
.FIRE WEATHER...
Moderate strength Santa Ana winds are expected to develop on
Tuesday and continue into Wednesday. Lowest daytime humidity on
Tuesday for inland areas will fall to 5-10% with poor recovery
Tuesday night. There will be a slight recovery on Thursday with
weaker winds. Greater recovery will occur for Friday and Saturday as
onshore flow returns and spreads higher coastal humidity inland.
Even though fuels may not be particularly responsive, the locally
strong and gusty winds, and very low RH will bring periods of
elevated fire weather conditions Tuesday through Wednesday,
primarily along the coastal slopes of the mountains into the
adjacent inland valleys and far inland Orange County.
&&
.AVIATION...
300340Z...Areas of stratus with bases 800-1100 ft MSL will fill in
along the coast and spread 10 to locally 15 mi inland tonight, with
bases gradually rising to around 1000-1400 ft MSL. Local vis 4-6 SM
possible over higher coastal terrain and on the coastal mesas
tonight. Stratus and vis restrictions clearing 14-16Z. Low clouds
may briefing spread back into the San Diego County coast late
Tuesday afternoon generally between 31/00-04Z before clearing again.
Otherwise a few high clouds and unrestricted vis through Tuesday
afternoon.
W-NW winds of 20-30 kts with gusts to 40 kts will continue across
the mountains and deserts through 10Z. Winds will turn northerly 10-
13Z, strengthening below the Cajon Pass and into the Santa Ana
Mountains as well as below the Morongo Pass into the northern
Coachella valley. North wind gusts of 30-40 kt likely in these areas
Tuesday morning through late Tuesday afternoon, weakening slightly
in the evening. Areas of MOD-STG up/downdrafts and LLWS possible on
the leeward side of the mountains through Tuesday evening.
&&
.MARINE...
No hazardous marine conditions are expected through Friday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 6 AM Tuesday to 2 PM PDT Wednesday for San
Bernardino County Mountains-San Bernardino and Riverside
County Valleys-The Inland Empire.
Wind Advisory from 6 PM Tuesday to 2 PM PDT Wednesday for Santa
Ana Mountains and Foothills.
PZ...NONE.
&&
PUBLIC...Gregoria/10
AVIATION/MARINE...SSThe national radar mosaic for the moment the first event began.
1 astronomical low tide. Local standard time, as filed.
Gusty winds occurred across the region with Highland Springs RAWS peaking at 65 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, 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: 950877.