Two storm systems impacted central California From February 17 to 20. A quickly-moving cold front came through the region on the 17th, causing minor nuisance flooding and gusty winds.
Every event with a place to put it. 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 MTR wrote it up.
Two storm systems impacted central California From February 17 to 20. A quickly-moving cold front came through the region on the 17th, causing minor nuisance flooding and gusty winds. A second, deeper but slower moving, system followed the next day with widespread rain and gusty winds. A warm front associated with this low came through the region late on Sunday the 18th, followed by the associated cold front and associated thunderstorms on Monday the 19th. With the longer period of rainfall and soils being saturated, shallow landslides were reported across the region.
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 Francisco Bay Area, CA wrote its last area forecast discussion before the first event at Feb 17, 2:40 PM PST, 1 hour 33 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco CA
240 PM PST Sat Feb 17 2024
...New SYNOPSIS, SHORT TERM, LONG TERM...
.SYNOPSIS...
Issued at 230 PM PST Sat Feb 17 2024
Light to moderate rain continues through the evening today. A
break in the rain/wind expected overnight but conditions quickly
worsen Sunday mid-morning as a strong Pacific low moves towards
the CA coast. Strong southerly winds, moderate to heavy rain, and
increased flooding concerns are expected Sunday into Monday.
Conditions improve by Tuesday, but lingering showers and residual
flooding remain possible.
&&
.SHORT TERM...
(This evening through Sunday)
Issued at 230 PM PST Sat Feb 17 2024
A weakening cold front that is drawing in subtropical moisture
continues to slowly push east towards the CA coastline, resulting in
generally light rain across the region. MRMS surface radar precip
rate indicates rain rates are around 0.15" per hour or less. This
checks out given that 12 hour rainfall totals as of 1PM have been
on the light side with 0.25-0.30" across the coastal mountains
and <0.20" across the interior with less than 0.10" across rain
shadowed valleys. As a result, there have not been any flooding
reports thus far from CHP and gauges on creeks/streams are not
responding and holding steady, which is good news. However, the
rain isn't over yet and an additional 0.15-0.75" is expected
through the evening today with locally higher rain rates possible
as the front gets closer, offering better forcing. But still
expecting minor impacts from today's system (system #1).
As system #1 weakens and exits the Bay Area and Central Coast this
evening, a break in the rain and wind is still expected overnight
through early Sunday morning. This break will not last long with
system #2, a deep Pacific low, approaches the CA coastline and will
start impacting our region by Sunday mid-morning. The Flood Watch
that encompasses the entire forecast area is set to start at 10 AM
Sunday.
By tomorrow mid-morning, the warm front will approach the region,
bringing warm, stratiform rainfall. Winds will start to increase
as well as a southerly low level jet approaches the coastline,
bringing gusts of 30 to 45 mph (stronger near the coast and at
higher elevations). After the warm front passes sometime tomorrow
afternoon- evening, calmer conditions may briefly prevail with
diminishing winds and rain activity. However, heavier, more
convective rain showers and persistently strong southerly winds
will be quickly develop as the cold front inches closer to the
coastline late Sunday into Monday.
Thunderstorms continue to look increasingly probable Sunday
overnight through much of Monday as colder air aloft moves in,
destabilizing the atmosphere. Heavier rain, locally gusty winds,
small hail, and lightning are all hazards associated with
potential thunderstorms that may develop. Locally heavier rain
rates have the potential to create more flash flooding concerns.
While flooding impacts will be minor at most today, the soils have
become saturated which will further exacerbate flooding concerns
as system #2 rolls through tomorrow-Mon. Tomorrow we will likely
see more reports of roadway flooding, downed trees, and power
outages. Use caution and if able, probably best to stay at home to
avoid problems on the roads.
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 230 PM PST Sat Feb 17 2024
While it is projected to weaken and continue lifting to the north,
the area of low pressure is expected to hang out near the
NorCal coast into Monday, providing persistent lift for showers
to continue through at least Tuesday. Luckily, the main moisture
plume will depart our area and meander south, impacting the SoCal
area. So we won't continue to see persistent, heavy rain on Monday,
but more so scattered showers that may be heavy at times. By
Tuesday, winds reduce and shower activity continues on the
downward trend. However, water levels on creeks and rivers will
continue to be elevated. Lingering showers still possible into
Wednesday.
Thursday and Friday next week are expected to be dry as ridging
develops over the Great Basin.
&&
.AVIATION...
(18Z TAFS)
Issued at 958 AM PST Sat Feb 17 2024
Lower CIGs are arriving with showers as the cold front builds into
the region. Expect strong southerly gusts this afternoon and into
the evening a the front crosses over the area. Stronger winds aloft
will cause LLWS concerns for the SF Bay and North Bay Terminals.
Winds and rain chances reduce into the night with lingering shower
activity. The next front arrives into Sunday afternoon with
southerly winds building again in the late morning before the
stronger chances for rain arrives.
Vicinity of SFO...Becoming MVFR as the rain arrives. Expect strong
southerly winds gusting above 30 kts with even stronger winds aloft,
causing concerns for LLWS. Rains will also cause a reduction in
visibility. Expect winds and rain chances to reduce into the night,
with lingering scattered showers. Another round of strong winds
build into Sunday afternoon with increasing showers.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Winds increase into the afternoon as the
more consistent rain arrives. Expect breezy southeast winds gusting
above 25 kts along with moderate rain that can reduce visibility.
Rain rates reduce into the night with scattered showers and lighter
winds expected. Stronger southeast winds arrive mid to late Sunday
morning ahead of the next big rainmaker.
&&
.MARINE...
(Today through Thursday)
Issued at 958 AM PST Sat Feb 17 2024
A cold front is bringing rain showers and strong southerly winds
across the waters. A large, long period westerly swell will also
propagate through the waters this weekend. The combination of gale
force gusts and building swell will result in hazardous
conditions for small and medium- sized vessels, with significant
wave heights of 14-17 feet expected. Additional rain and gusty
winds arrive along another system Sunday into early next week.
Seas will remain elevated through Tuesday before gradually abating
below 12 feet on Wednesday.
&&
.BEACHES...
Issued at 1000 AM PST Sat Feb 17 2024
A high surf advisory is in effect through 4 PM Sunday.
Incoming large westerly is causing large breaking waves of 18 to
22 feet along exposed, west- facing beaches. Locally higher waves
of 28 feet are possible along some favored areas with steep
beaches. In addition to the westerly swell, strong southerly winds
will enhance the energy in the surf zone, creating dangerous
conditions for surfers and swimmers. Inexperienced swimmer should
remain out of the water. All beachgoers are strongly encouraged to
respect the power of the ocean and reminded to never turn their
back to the water. Large waves can sweep across the beach without
warning, pulling people into the sea from rocks, jetties, and
beaches. These waves can also move large objects such as logs,
crushing anyone caught underneath.
&&
.HYDROLOGY...
Issued at 1000 AM PST Sat Feb 17 2024
A flood watch is in effect from 10 AM Sunday through 10 AM
Wednesday. Excessive runoff may result in flooding of rivers,
creeks, streams, and other low-lying and flood-prone locations.
Creeks and streams may rise out of their banks. Flooding may occur
in poor drainage and urban areas. While most main stem rivers are
forecast to remain below flood stage, minor flooding in urban
areas and along smaller creeks and streams is expected. A flood
watch means flooding is possible. Monitor the latest alerts for
possible flood warnings.
Soil moisture remains high from previous storms earlier this
month and will reach saturation this weekend. Once saturated,
additional rainfall will runoff resulting in moderate to rapid
rises on our creeks, streams, and rivers, as well as lead to
nuisance and/or minor flooding. Latest river forecasts from the
CNRFC depict an initial rise on area creeks, streams, and rivers
on Saturday and Saturday night with a larger rise on Monday and
Tuesday. The current ensemble guidance from the CNRFC indicates
the Russian River at Guerneville and the San Lorenzo River at Big
Trees have about a 20% chance of reaching flood stage in the next
5 days, while the Salinas River at Spreckels and Pajaro River at
Chittenden will be slower to crest and have about a 15% chance of
reaching flood stage in the next 10 days. Although most sites are
forecast to remain below flood stage, some locations may reach
monitor stage or minor flood stage.
USGS instrumentation throughout the San Francisco Bay Area
indicates that shallow soils on steep hillsides are approaching
saturation. This coupled with the forecasted precipitation means
shallow landslides are possible. Expect localized ponding of
water in low-lying or poorly drained areas, such as freeway
offramps.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 4 PM PST Sunday for CAZ006-505-509-529-
530.
Flood Watch from Sunday morning through Wednesday morning for
CAZ006-502>506-508>510-512>518-528>530.
Wind Advisory from 10 AM Sunday to 4 AM PST Tuesday for CAZ006-
502>506-508>510-512>518-528>530.
PZ...Small Craft Advisory until 9 PM PST this evening for SF Bay N of
Bay Bridge.
Small Craft Advisory from 9 AM Sunday to 3 AM PST Monday for SF
Bay N of Bay Bridge.
Small Craft Advisory until 3 AM PST Monday for Mry Bay.
Gale Warning until 9 PM PST this evening for Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt
Reyes 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt
Reyes to Pigeon Pt 0-10 nm.
Gale Warning from 3 AM Sunday to 3 AM PST Monday for Pt Pinos to
Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 AM PST Sunday for Pt Arena to Pt
Reyes 10-60 NM.
Gale Warning from 9 AM Sunday to 3 AM PST Monday for Pt Arena to
Pt Reyes 10-60 NM.
&&
SHORT TERM...McCorkle
LONG TERM....McCorkle
AVIATION...Murdock
MARINE...Murdock
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www.youtube.com/nwsbayareaPreliminary Local Storm Report
National Weather Service San Francisco CA
347 PM PST Sat Feb 17 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0322 PM Landslide SR116/Old Monte Rio Rd 38.50N 123.01W
02/17/2024 Sonoma CA Law Enforcement
Large rockslide blocking WB lane of WB 116
just east of Old Monte Rio Rd.
&&
NSThe Sacramento radar (KDAX), 145 km away, was scanning. The volume nearest the first event began at 00:14 UTC.
28 flood, 2 thunderstorm wind. Local standard time, as filed.
Roadway flooding was reported at California Route 1 and Kruse Ranch Road. A vehicle was stuck in mud on the right hand side of the road.
Flooding blocked the northbound lanes of California Highway 1 at Bear Valley Road.
Standing water was reported halfway across Occidental Road in two different spots between Mill Street and California Highway 116.
Approximately 3 inches of water rushed across Calistoga Road before and after Alpine Road.
Localized flooding was reported around Point Reyes Station and Inverness Park.
Westbound Lucas Valley Road west of 101 was completely flooded.
Roadway flooding was reported at Arnold Drive and Boyes Blvd.
Water flooded the roadway at northbound Olivet Road at Piner Road.
Roadway flooding was reported on California Highway 1 at Tomales-Petaluma Road.
Roadway flooding was reported at eastbound California Highway 116 and Bloomfield Road.
A landslide blocked eastbound lanes of Mark West Springs Road.
Both offramps from Interstate 80/580 to Ashby Avenue were flooded.
A 6 inch deep puddle in the slow lane of westbound Interstate 80.
A vehicle was stuck in a flooded roadway on Valley Ford Road.
A vehicle was stuck in water on eastbound Interstate 580 near Castro Valley, with lanes 4 and 5 flooded.
Roadway flooding was reported at the High Street onramp to northbound Interstate 880.
Flooding blocked the number 2 lane of the connector from southbound Interstate 680 to westbound Interstate 580.
Flooding was reported in the number 3 and 4 lanes of northbound Interstate 280 just south of California Highway 87.
California Route 12 was closed until 8 AM due to flooding from Fremont Drive to Watmaugh Road.
Number 2 and 3 lanes of southbound California Highway 87 just north of California Highway 85 flooded with about 6 inches of water 100 feet before connector ramp.
About 3 feet of water flooded the offramp from northbound California Highway 17 to Bear Creek Road.
The number 3 and 4 lanes of southbound Interstate 680 were flooded just south of McKee Rd.
The slow lane of Northbound Interstate 880 was flooded just south of California Highway 262.
Creek flowing over Mark West Station Road after heavy rainfall.
A 3 foot diameter tree fell onto the roadway at California Route 236 and China Grade Road.
Mud, dirt, and rock blocking Los Alamos Road.
A large portion of a tree leaned against utility lines on Tubbs lane at California Highway 29.
Flooding at US Highway 101 at Abbott Street.
Old Stage Road was closed a Chualar Road due to flooding.
Several inches of water were flowing over streets and spraying out of manhole covers near San Francisco City Hall.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2024Every state in 2024This day in weather historyWarnings in California, February 2024
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: 1154990, 1154991, 1154992, 1154993, 1154995, 1154994, 1154996, 1155000, 1154999, 1154998, 1154997, 1155002, 1155003, 1155004, 1155006, 1155008, 1155013, 1155014, 1155016, 1155017, 1155018, 1155019, 1155020, 1155021, 1155023, 1155022, 1155024, 1155025, 1155027, 1155030.