Multiple weather systems moved through California from December 26 to 29, bringing localized flooding and gusty winds to the region.
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 MTR wrote it up.
Multiple weather systems moved through California from December 26 to 29, bringing localized flooding and gusty winds to 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 Dec 26, 3:42 PM PST, 2 hours 57 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco CA
342 PM PST Thu Dec 26 2024
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 136 PM PST Thu Dec 26 2024
Multiple weather systems will move across northern California this
weekend, bringing periods of rain to the region along with a new
northwest swell arriving today. Dangerous surf and beach conditions
are expected into the weekend. Dry weather should arrive for the
early part of next week, which could lead to some cold morning
temperatures.
&&
.SHORT TERM...
(This evening through Friday)
Issued at 136 PM PST Thu Dec 26 2024
Satellite imagery shows a blanket of clouds covering much of the
region this afternoon. Most of the area should remain dry, with
chances for rain returning to the North Bay later this afternoon and
then slowly spreading south overnight. Winds increase in response
tonight and into early tomorrow morning. The forecast still calls
for the coastline, the ridgetops, and the gaps and passes to have
gusts of 30-35 mph with this system, and 20-25 mph gusts are
possible in the valleys. While below wind advisory criteria, winds
could still pose a threat for difficult driving conditions for high
profile vehicles or holiday decorations. Rainfall totals through
Saturday morning are forecast to be 1-1.5 inches for the North Bay
Valleys, 1.5-3.0 inches for the North Bay mountains, 0.5-1 inch for
the San Francisco Peninsula and East Bay counties, 0.25-0.5 inches
for the South Bay valleys, 0.5-1.5 inches for South Bay mountains, 1-
2 inches for the Santa Cruz Mountains, for Monterey-Salinas region
and the Big Sur Coast (locally up to 1" in the Santa Lucias), and up
to 0.1" in the interior Central Coast valleys.
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 136 PM PST Thu Dec 26 2024
Zonal flow through the early portion of the weekend will let
additional disturbances pass over us, keeping our weather wet. An
upper level trough barrels through the PacNW Sunday into early
Monday, which should be the last hurrah for rain for us as ridging
builds behind it. This period of ridging will let colder air nestle
into the region, leading to some chilly mornings for the start of
the work week. Will need to keep an eye out for any sort of frost
advisories for the North Bay Valleys and interior Monterey and San
Benito counties as temperatures look to fall into the 30s. Beyond
that, ensemble and model guidance start to differ around the New
Year / beginning of January. Kept NBM guidance in for now as it
advertises light rain for the North Bay counties and San Francisco
peninsula.
&&
.AVIATION...
(00Z TAFS)
Issued at 341 PM PST Thu Dec 26 2024
Spotty lower CIGS and prevailing mid-level clouds continue to affect
the area. Winds stay light to moderate into the night. The next cold
front enters the area overnight with light showers and building
southerly winds ahead of it. As the main rain band moves through,
expect strong southerly winds and moderate rainfall along with lower
CIGs. Visibilities will also be reduced. The main rain band exits
into the mid morning, but some light showers linger behind along
with mist and lingering lower CIGs.
Vicinity of SFO...Mid-level cloud continue to move through the area.
Expect mostly light winds into the night. Southerly winds become
gusty overnight as the pre-frontal showers arrive. MVFR CIGS build
in the late night as the main rain band enters the SF Bay. Expect
gusty southwest winds, reduced visibilities and lowering CIGs as the
front moves through. Behind the front, expect light shower activity
and persistent MVFR CIGs for the rest of Friday morning. VFR returns
Friday afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...MVFR CIGs return overnight. Expect mostly
light winds until the late night as the next cold front nears, with
more gusty, southerly winds. Moderate rain along the front will
reduce visibility. CIGs lower further in the misty post-frontal
environment as winds reduce.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 341 PM PST Thu Dec 26 2024
High long-period swell continues to build into the waters. Strong
SW winds and rough seas will persist through into the weekend,
before winds turn Northwest on Sunday. A series of weather systems
will bring showers and slight chances for storms Thursday night
through the weekend. Conditions will improve into the next work
week as winds reduce and the swell abates.
&&
.BEACHES...
Issued at 1100 AM PST Thu Dec 26 2024
A High Surf Advisory is in effect through 4 PM Sunday. Large NW
swell is arriving to the coastal waters and will persist through
the weekend. Satellite observations and wave models continue to
suggest the swell will be roughly 15 feet high with a 15 second
period. That translates to 20-30 foot breaking waves, depending on
the beach orientation and bathymetry (beach slope). The waves now
look to peak Friday and abate through the day Saturday. If that
trend holds, we may have to shorten the advisory duration. While
these waves are smaller than the monsters we got on Monday, the
coast is still dangerous. Inexperienced swimmers should stay out
of the water, wave watchers should maintain a a safe distance, and
no one should ever turn their back on the ocean. Let's get
through this weekend without another ocean fatality.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 4 PM PST Sunday for CAZ006-505-509-529-
530.
PZ...Small Craft Advisory from 9 PM this evening to 9 AM PST Friday
for SF Bay N of Bay Bridge.
Small Craft Advisory until 9 AM PST Saturday for Mry Bay-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.
Small Craft Advisory until 9 PM PST this evening for Pt Arena to
Pt Reyes 10-60 NM.
Gale Warning from 9 PM this evening to 3 AM PST Friday for Pt
Arena to Pt Reyes 10-60 NM.
&&
SHORT TERM...KR
LONG TERM....KR
AVIATION...Murdock
MARINE...Murdock
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www.youtube.com/nwsbayareaThe national radar mosaic for the moment the first event began.
26 flood, 3 high wind. Local standard time, as filed.
Mudslide and small rocks in lanes of State Route 128 at Maacama Ridge Road.
State Highway 1 was completely flooded just south of mile marker 27.
Roadway flooding was reported on Interstate 580 near Emeryville.
One foot of water was reported on both lanes of Pepper Road and Center Road.
Water was reported across all lanes of eastbound State Highway 24 at the junction with St Stephens Drive.
Roadway flooding was reported on US Highway 101 Northbound near Larkspur.
The gauge on Colgan Creek near Sebastopol reported a moderate flood stage.
Vehicle stuck in floodwaters on Bodega Highway near Freestone.
An emergency manager reported that lower Mill Valley was experiencing localized flooding and a few road closures.
Roadway flooding was reported at Hartnell and Alisal Road.
Flooding was reported in a lane on Interstate 238.
Rogge Road and San Juan Grade Road closed due to flooding.
The Cobb Ridge West PG&E Mesonet station reported a gust of 57 mph.
The Road To Ranches PG&E Mesonet station reported a gust of 57 mph.
Rocks in lanes on State Highway 1 south of Fairfax Bolinas Road.
Flooding across all lanes of southbound US Highway 101 south of the Van Ness Avenue onramp.
Flooding reported on eastbound Interstate 80 at Pinole Valley Road.
Floodwaters 3 inches deep along northbound Interstate 880 at Broadway.
Large rocks moved to the side of Deer Park Road at Sunnnyside Road.
Valley Ford-Freestone Road was closed between Bodega Highway and State Route 1.
The South Black Diamond Way PG&E Mesonet station reported a gust of 59 mph.
Connector between westbound Interstate 580 and eastbound State Highway 24 partially flooded.
Flooding caused the closure of Valley Ford Road between Gericke Road and California Route 1.
Mud and debris on the onramp from 7th Street to southbound Interstate 880.
Roadway flooding reported on southbound Crow Canyon Road just north of Norris Canyon Road.
Flooding on Mirabel Road at River Road trapped a vehicle.
Water was 2 inches deep along northbound Interstate 880 at the 66th Avenue offramp.
Mud, dirt, and rocks were blocking half of the southbound lane of State Highway 9 near Paradise Park.
Rock slide partially blocking northbound Big Basin Way at Little Basin Road.
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, December 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: 1229336, 1229332, 1229446, 1229333, 1229334, 1229335, 1229378, 1229447, 1229380, 1229381, 1229448, 1229383, 1229385, 1229387, 1229391, 1229392, 1229393, 1229394, 1229395, 1229396, 1229384, 1229438, 1229440, 1229441, 1229442, 1229444, 1229445, 1229397, 1229399.