Flooding and Heavy Snow in California, February 19 to 21, 2024

Name: Flooding and Heavy Snow in California, February 19 to 21, 2024
Start: 2024-02-19T21:00
End: 2024-02-21T10:00
Location: California

February 19 to 21, 2024 · NWS SGX · 6 events in 5 counties and zones

Where it happened

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.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 6

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.

What happened

The episode as NWS SGX wrote it up.

A storm system produced moderate to locally heavy rainfall across Orange and San Bernardino Counties, with lesser amounts farther south and east. Over an inch of rain fell across the aforementioned areas, with some locations seeing up to 3 inches of rain. One to two feet of snow fell across the San Bernardino County Mountains. While lesser rain fell across San Diego County, locally heavy rain rates lead to several traffic incidents.

What forecasters said that day

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 19, 1:52 PM PST, 7 hours 8 minutes earlier.

Area forecast discussion, Feb 19, 1:52 PM PST, 7 hours 8 minutes before

Area Forecast Discussion
National Weather Service San Diego CA
152 PM PST Mon Feb 19 2024

.SYNOPSIS...
Periods of rain and mountain snow are expected through Wednesday.
The heaviest precipitation will fall over Orange County, the San
Bernardino County mountains, and northern San Diego County Tuesday
into Wednesday morning. There is a slight chance of thunderstorms
mainly for the coast and valleys Wednesday morning. Periods of gusty
southwest to west winds are expected late Tuesday into Wednesday
over the mountains locally into the deserts. Dry conditions expected
by late Wednesday afternoon and will continue into at least Friday.
Another Pacific low pressure system will bring additional chances
for precipitation early next week.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Periods of light showers are occurring across Orange County, locally
into the Inland Empire, and on the coastal slopes of the San
Bernardino county mountains at 2 PM. Rainfall accumulations over the
past 12-hours have been mostly 0.05-0.15 inches for Orange County
and the Inland Empire, locally up to 0.30 inches. The San Bernardino
county mountains have accumulated 0.50-1 inch. Shower activity is
expected to move further south into San Diego county through this
evening and overnight. Rain overnight is expected to be light, but
the passage of a shortwave closer to sunrise Tuesday morning could
generate areas of moderate to locally heavy rain, especially in
Orange County and in the foothills of the San Bernardino county
mountains.

Scattered, mostly light, showers are expected mid-morning Tuesday
through Tuesday afternoon. High resolution model guidance is
indicating more moderate to heavy rain will develop sometime late
Tuesday afternoon into early Wednesday morning with the passage of
the final trough of this series of systems. This trough passage is
expected to tap into the lingering available moisture in the
atmosphere, bringing more widespread precipitation, that will be
heavy at times. Even with the event basically upon us, there are
still some discrepancies amongst the available guidance, mainly in
regards to the timing and placement of the heaviest precipitation.
Current forecast does have an increase in rainfall totals for San
Diego county for late Tuesday into early Wednesday morning. Colder
air aloft will provide enough instability for at least a slight
chance of thunderstorms, mainly for the coastal areas and valleys.
The trough moves out quickly with precipitation coming to an end by
late Wednesday afternoon.

Rainfall totals for Tuesday morning through Wednesday afternoon are:
1.00-1.75 inches for Orange County and Inland Empire; 0.75-1.30
inches for San Diego county with higher totals in northern San Diego
County; 1-2 inches for the Santa Ana, San Diego, and Riverside
County mountains; 2-4 inches for the San Bernardino County
mountains; 0.30-0.50 inches for the High Desert; 0.10-0.25 inches
for the lower deserts.

Snow levels will be high through Tuesday morning - generally around
8000 ft or higher - falling to around 7000-7500 ft Tuesday
afternoon, and then 6000-6500 ft Wednesday morning. Snow totals for
early Tuesday through Wednesday afternoon are 1-5 inches between
6,000 to 7,000 ft, 5-10 inches from 7,000 to 8,000 feet, and up to 1-
2 feet above 8,000 ft.

Periods of gusty southwest to west winds are expected over the
mountains and locally into the deserts late Tuesday into Wednesday.
Peak wind gusts of 40 to 50 mph are expected. Winds in the deserts
will peak at 30 mph in the High Desert and the San Diego County
deserts.

Zonal flow and weak ridging will bring warmer and drier weather
Thursday and Friday. A touch of offshore flow will help with the
warming on Friday when highs in some of the valleys and inland
Orange County could reach the low 70s. The break in the weather is
short lived, with another closed low forecast to move out of the
Gulf of Alaska towards California on Saturday. While ensemble
guidance is indicating most of the area will get measurable
precipitation, there is still considerable uncertainty surrounding
precipitation amounts and timing. The fastest solutions, though in
the minority, bring precipitation in as early as Saturday evening,
with the slowest holding off until sometime late Sunday or Monday.
The low is currently forecast to dig much further south than this
current system, there is a chance it could be colder with lower snow
levels. In addition to precipitation chances cloudy and windy
conditions with highs several degrees below normal Sunday and Monday
are expected.

&&

.AVIATION...
192030Z...Coast/Valleys/Mountains...Multiple cloud layers with SCT-
BKN 2000-3000 FT MSL, OVC 3500-4500 FT MSL. SCT -SHRA continuing
across Orange Co and the Inland Empire this afternoon, with lower
bases 800-1500 FT MSL and reduced vis of 1-3 SM. SHRA spreading
farther south and east into Riverside/San Diego Co after 00z Tue.

Desert Slopes/High Desert...Gusty SW over the mtns/desert slopes
through 02z Tue with peak gusts 35-45 kt.

Otherwise, FEW AOA 15,000 with unrestricted VIS through tonight.

&&

.MARINE...
A Pacific storm will bring a 5-10 foot west swell with a 16-19 sec
period today, and a 6-11 foot/14-17 sec swell Tuesday. Southerly
wind gusts of 20 to 25 knots will be possible Tuesday night into
Wednesday. Periods of rain will occur today through Wednesday, with
the highest chances late tonight into Wednesday morning.

&&

.BEACHES...
The first of two west swells, producing surf of 6-10 feet with sets
to 10 feet on west-facing beaches, will decrease slightly today
before the second swell arrives tonight and continues through
Tuesday. The swell height will be slightly greater, to 11 feet, but
the period will be slightly lower, 14-17 seconds, so similar surf
heights will occur Tuesday. Minor tidal overflow will likely occur
through Tuesday during the early morning highs tides of 5.0-5.4 ft.
Swell and surf will subside Wednesday.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 10 PM PST Tuesday for Orange County
     Coastal Areas-San Diego County Coastal Areas.

     Flood Watch from 10 PM PST this evening through Wednesday
     morning 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 Diego County Coastal Areas-
     San Diego County Mountains-San Diego County Valleys-San
     Gorgonio Pass Near Banning-Santa Ana Mountains and
     Foothills.

     Winter Weather Advisory from 1 AM Tuesday to 10 AM PST Wednesday
     for Riverside County Mountains-San Bernardino County
     Mountains.

PZ...Small Craft Advisory until 10 AM PST 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...CO
AVIATION/MARINE/BEACHES...EA

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 heavy rain, 2 flood, 1 heavy snow. Local standard time, as filed.

Heavy Rain, Orange

When: February 19, 9:00 PM PST to February 21, 10:00 AM PST
Where: Orange County, 1.53 mi NE of (Sli)aaf Los Alamito to 0.55 mi E of Liberty Park
Reported by: Mesonet
Coordinates: 33.748, -118.065

Heavy rain fell across Orange County from late in the evening on February 19 through the morning on February 21. The following are the heaviest rain reports from the coast, valleys and mountains:

Heavy Rain, San Bernardino

When: February 19, 10:00 PM PST to February 21, 10:00 AM PST
Where: San Bernardino County, 1.04 mi W of Rialto Muni Arpt to 1.14 mi W of Moonridge
Reported by: Mesonet
Coordinates: 34.132, -117.398

Heavy rain fell across San Bernardino County from late in the evening on February 19 through the morning on February 21. The following are the heaviest rain reports from the Inland Empire through the mountains:

Heavy Rain, Riverside

When: February 19, 10:00 PM PST to February 21, 10:00 AM PST
Where: Riverside County, 1.85 mi ESE of Riverside to 1.54 mi ENE of Mountain Center
Reported by: Mesonet
Coordinates: 33.937, -117.372

Heavy rain fell across Riverside County from late in the evening on February 19 through the morning on February 21. The following are the heaviest rain reports from the Inland Empire:

Inland Empire:|Norco (650'): 1.14|Prado Dam (460'): 1.06.

Heavy Snow, San Bernardino County Mountains

When: February 20, 1:00 AM PST to February 21, 10:00 AM PST
Where: San Bernardino County Mountains forecast zone
Reported by: County Official
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

Moderate to locally heavy snow fell across the San Bernardino County Mountains early in the morning on February 20 through February 21.

Flood, San Diego

When: February 20, 10:00 AM PST to 11:30 AM PST
Where: San Diego County, 1.35 mi ESE of Carlsbad to 0.99 mi SSE of Carlsbad
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 33.160, -117.330

Water was running across the freeway on Northbound I-5 in Carlsbad. A plow was required to clean up dirt in the lanes following the flooding.

Flood, San Diego

When: February 21, 4:30 AM PST to 6:00 AM PST
Where: San Diego County, 1.81 mi NE of Encanto to 1.23 mi S of La Mesa
Cause: Heavy Rain
Reported by: Broadcast Media
Coordinates: 32.740, -117.050

Two lanes on SR94 were flooded creating a major traffic jam. Multiple observation sites recorded rainfall rates of 0.30 to 0.50 inch per hour.

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2024 Every state in 2024 This day in weather history Warnings in California, February 2024

Sources

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: 1163957, 1163959, 1163961, 1163962, 1163099, 1163098.