A cold front swept through the region on the 7th bringing gusty southerly winds, heavy rain, and flooding. Winds brought down trees and power lines across the greater Bay Area resulting in injuries to two people in San Francisco.
Every event with a place to put it; 10 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.
A cold front swept through the region on the 7th bringing gusty southerly winds, heavy rain, and flooding. Winds brought down trees and power lines across the greater Bay Area resulting in injuries to two people in San Francisco. Downed power lines also left over 1,000 people without power in the Santa Cruz Mountains as well as causing several additional power outages across San Francisco. A line of strong showers moved over San Francisco bringing urbanized flooding to the city and strong winds. Roads as well as municipal stations were underwater.
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 6, 9:59 AM PST, 3 hours 1 minute earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
959 AM PST Fri Dec 6 2019
.SYNOPSIS....Southerly winds will continue to increase today ahead
of an incoming cold front. Rain will develop across the North Bay
this afternoon and then spread southward tonight. Showery and
cool on Saturday with isolated thunderstorms possible. Lingering
showers on Sunday but trending drier by afternoon. Dry weather
returns Monday and Tuesday with a slight chance of rain by
midweek.
&&
.DISCUSSION...as of 8:52 AM PST Friday...Satellite imagery shows
the approaching storm system approximately 640 miles due west of
Cape Mendocino, with the associated frontal band nearing the
North Coast. Latest computer models continue the trend of slowing
down the arrival of this system. The 12Z Nam has the frontal band
moving into Sonoma County just after 00Z (4 PM PST) and holds off
rain in San Francisco until after 7 PM. The bulk of the rainfall
with this first wave is forecast to fall in the North Bay, and to
a lesser extent, the Santa Cruz Mountains. A second front will
sweep through the entire district on Saturday and will bring more
rainfall to the area through Saturday evening, along with a slight
chance of thunderstorms with small hail possible. The upper low
will then finally move south along the coast on Sunday keeping
showers going in its vicinity as it exits the area Sunday night.
Latest storm-total rainfall estimates still show some 3-4 inch
maxes for the North Bay hills with 1.5-3 inches for the Santa
Cruz/Santa Lucia mtns. Rain shadowed Santa Clara/Salinas Valleys
0.25-0.50 on average with 0.50-1.00 inch elsewhere through Sunday
night.
The Flash Flood watch for the Kincade burn area still looks valid
with all models showing a bullseye of qpf in that area and the
front strongest as it moves through northern Sonoma county this
evening. Will need to monitor any convective lines and short term
rain rates that could lead to problems over the burn area.
A Wind Advisory remains in effect for all areas beginning later
this morning and continuing into Saturday morning. Strongest winds
are expected along the coast and in the higher terrain. Gusty
southeast winds will persist well into Saturday as the second
front moves through.
Dry weather returns Monday and Tuesday with seasonable
temperatures as high pressure rebuilds. A weak front may try and
knock into the ridge by Weds with a slight chance of rain but not
expecting anything of significance at this time.
&&
.AVIATION...as of 10:00 AM PST Friday...For 18z TAFS. Storm system
has once again slowed down in latest guidance, pushing the timing
back versus the previous TAFs. Frontal boundary looks less robust
as it pushes south of the North Bay as well. That said, expecting
very unsettled weather throughout the TAF for the North Bay and
the latter half of the TAF for the remaining areas. Many impacts
to aviation with this system from wet runways, an extended period
of low level wind shear at around 2000 feet, and erratic stronger
winds mixing down to the surface, south-southeast winds, and
generally MVFR ceilings. Rain showers will come and go in the wake
of the front at many TAF sites, making it difficult to pin down
the periods of intermittently worse conditions.
Vicinity of KSFO...System has slowed down, delaying times versus
previous TAF. Periods of rain from 01-02Z onward now expected with
wet runways. Southeast winds throughout the period, increasing in
strength as front draws closer to the airport. LLWS at 2000 feet
at generally 35-50kt through the TAF. Infrequent gusts will mix
down to the surface of varying speed, some in excess of 35kt.
Intermittent ceilings in the 2000-4000 foot range by the afternoon.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Front is looking weaker by the time it
makes it to KMRY/KSNS, thus, weakened winds and delayed timing in
latest TAF. Fractured front arrives around 07-10Z tonight with
trailing rain showers into the morning. Valley favored SE winds
will bring very gusty conditions to KSNS through most of the TAF
period, while KMRY could be wind sheltered for much of the event.
That said, still expect to see limited LLWS / gusts at KMRY by
late this afternoon.
&&
.MARINE...as of 09:49 AM PST Friday...A storm system will move
through the waters from north to south over the next 24 hours,
bringing unsettled weather today into the weekend. As a result,
southerly gale force gusts will develop across the waters today.
These winds will generate large wind waves and hazardous seas.
Moderate west swell will gradually build to around 10 to 12 feet
tonight and continue through Saturday night. Showers and isolated
thunderstorms will be possible this evening through Saturday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...Wind Advisory...CAZ006-505>513-516>518-528>530
Flash Flood Watch...CAZ506-507
SCA...SF Bay until 3 PM
SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 PM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 PM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 PM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 PM
GLW...SF Bay from 3 PM
GLW...Pt Reyes to Pigeon Pt 0-10 nm from 3 PM
GLW...Pigeon Pt to Pt Pinos 0-10 nm from 3 PM
GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 PM
GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 3 PM
GLW...Pt Arena to Pt Reyes 0-10 nm
GLW...Pt Arena to Pigeon Pt 10-60 nm
SCA...Mry Bay from 3 PM
&&
PUBLIC FORECAST: Sims
AVIATION: DRP
MARINE: DRP
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www.youtube.com/nwsbayareaThe national radar mosaic for the moment the first event began.
16 flood, 13 strong wind, 2 debris flow. Local standard time, as filed.
Mesonet station (PG&E) on Old Coast Tower measured gusts between 45 and 55 mph with a peak gust of 61 mph.
Mesonet station (PG&E) recorded gusts over 45 mph with a peak gust of 56 mph.
Rock/mud slide blocking nb and sb lanes of SR-1 at Moonraker Rd.
Hawkeye station.
Mesonet station (PG&E) measured gusts over 45 mph with a peak gust of 54 mph.
Sea Ranch mesonet station.
Spring Valley RAWS recorded wind gusts between 45 and 49 mph.
Highway 1 just north of MacCarthur Tunnel flooded, 1 foot of water in lanes 2-3.
Calaveras Road RAWS station reported gusts between 45 and 48 mph.
Los Gatos RAWS station recorded gusts between 45 and 66 mph.
CHP reporting mud/dirt/rock along CA Hwy 1 near Limekiln Campground. Reports of full closure of northbound and southbound traffic for another hour or so.
Widespread flooding in the area on Labath Ave near the Rohnert Park Expressway W, one foot of water across northbound lane.
San Francisco Fire Department reporting two pedestrians injured at the intersection of Locus and Clay with a downed tree, likely brought down in the wind. Victims taken to a trauma center. Report from SFFD PIO twitter.
Flooding on 580 eastbound near Harrison St off ramp.
Widespread flooding across Oakland. CHP reports flooding across portions of several interstates including 580, 880, 980, and 80. Flooding ranges from 6 inches to 2-3 feet deep.
Downed power line hanging over roadway at Austin Creek Rd near Chimney Rock Rd.
CHP reports several freeways including 680 and 24 have flooding in some or all lanes.
Street flooding at intersection of Market St and Church St in San Francisco. Estimated 1 to 2 feet of water on roadway with widespread street flooding.
Flooding on 15th Ave and Wawona St in San Francisco. Widespread street flooding with 1-2 feet deep water estimated.
Report on twitter of roadway flooding on Fillmore and Broadway in San Francisco, estimated depth around 6 inches.
Flooding at intersection of Judah and 30th in Outer Sunset. Estimated 6 inches to 1 foot of water flowing down roadway. Flooding appears widespread.
Two vehicles stuck in flood waters. Hwy 101 northbound connector to Central Freeway is closed due to widespread flooding, 1 to 1 1/2 feet of water in roadway.
I-80 Asby off ramp and on ramp are closed due to flooding, vehicles stalled in 1 1/2 to 2 feet of water.
One foot water in basement of home in the Castro District, time estimated as owner was not home during flood. Exact location estimated on map.
Flooding in left lanes of I-280 N just before John Daly exit, estimated 1 foot of water.
Report on twitter of roadway flooding at Turk and Masonic Ave in San Francisco, estimated 6 inches of water.
Fallen trees have closed multiple roads in the Santa Cruz Mountains. Hwy 9 was closed after a vehicle crash involving a fallen tree and power lines between Ben Lomond and Brookdale. One driver was trapped inside a vehicle. SR 236 and Acorn Drive was also closed due to downed trees and power lines. More than 1,000 customers were without power https://www.ksbw.com/article/1000-without-power-highway-9-shutdown-after-tree-falls-on-power-lines-vehicle/30158848.
Roadway flooding reported in lane 4 of 580 eastbound.
Water running down the stairs into the Van Ness Municipal Station near Market St and Van Ness Ave, No SF municipal service between West Portal Station and Embarcadero Station due to flooding.
SFFD has been responding to downed trees and power lines. Over 20 power outages spread across San Francisco. Largest outage in Lower Haight. Also reporting localized flooding in multiple locations throughout the city.
Both directions of San Carlos Ave at Cordilleras Ave in San Carlos closed due to large fallen tree across roadway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, December 2019
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: 864875, 864876, 864661, 864862, 864877, 864860, 864866, 864645, 864867, 864869, 864662, 864646, 864663, 864647, 864648, 864664, 864649, 864650, 864651, 864652, 864653, 864654, 864655, 864656, 864657, 864658, 864667, 864659, 864660, 864665, 864666.