A weak cold front moved through into Christmas morning bringing scattered showers and gusty winds to the region. One report was received of a tree falling onto a house in Atherton.
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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 weak cold front moved through into Christmas morning bringing scattered showers and gusty winds to the region. One report was received of a tree falling onto a house in Atherton.
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 24, 10:39 PM PST, 3 hours 8 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
1039 PM PST Mon Dec 24 2018
.SYNOPSIS...The cold front that moved through the district earlier
today is now south of our area. Scattered showers will continue
tonight but end from the north by around sunrise tomorrow
morning. Christmas Day will be mostly sunny and seasonably cool.
Dry conditions, generally clear skies and seasonably typical
temperatures are then forecast to continue through the remainder
of the week.
&&
.DISCUSSION...As of 9:10 PM PST Monday...Latest GOES-17 IR
satellite imagery and KMUX radar returns show bands of postfrontal
cloudiness and embedded showers continuing to move through the
district. The upper low center itself now appears to be just a
bit inland from Cape Mendocino, with the whole system moving
pretty rapidly to the southeast. Just received new 00Z output from
the NAM and GFS remains consistent in ending precip around the
San Francisco and Monterey Bay regions by sunrise tomorrow, with
perhaps just a lingering early morning shower in the far
southeastern interior of the district.
To the contrary of earlier model output and statistical guidance,
no lightning/thunderstorms were detected or reported anywhere in
our CWA (and none are expected tonight). Rainfall totals were
generally pretty modest, with 1.31 inches at the RAWS site on top
of Mt Tam the largest noted thus far. Downtown San Francisco has
received 0.48 inches. On the other hand, a brief burst of
moderately strong and gusty west to northwest winds did accompany
the frontal passage itself. Max peak winds noted at lower
elevations included 48 mph at both KSFO and KHWD, 47 mph at
midpsan of the Golden Gate Bridge, and 43 mph on Amorco Pier, out
into the Carquinez Straits at Martinez.
Present forecasts for Christmas Day and on through the remainder
of the week remain on track. Dry weather, mostly clear skies
aside from some passing high cloudiness at times, and generally
seasonable temperatures continue to be expected. An "inside
slider" type system will brush by to our east around Thursday
morning, but expect consequences for us to be limited to some high
cloudiness ahead of it Wednesday afternoon and evening, and
breezier conditions Wednesday afternoon through Thursday.
Finally, will note that latest model output is trending a bit
chillier with min temps early Wednesday morning in our colder
valley locations, and may ultimately need to add in some mention
of patchy frost.
&&
.AVIATION....as of 10:39 PM PST Monday...Mainly MVFR except LIFR-
IFR in occasionally heavy showers overnight and early Christmas
morning. Tafs are a blend of the HRRR and NAM model qpf and NAM
MOS ceiling guidance.
Vicinity of KSFO...MVFR tempo IFR 06z-10z due to heavy showers.
A few lingering morning showers possible otherwise drier with VFR.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...MVFR tempo IFR 06z-10z due to heavy showers.
A few lingering morning showers possible otherwise drier with VFR.
&&
.MARINE...as of 8:27 PM PST Monday...Gale force gusts will
continue overnight behind the cold front, showers will end by
sunrise. Gusty northerly winds and fresh seas will continue
Wednesday through Friday as high pressure builds and strong
pressure gradients set up near Cape Mendocino.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...GLW...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
GLW...Pt Arena to Pigeon Pt 10-60 nm
GLW...Pt Pinos to Pt Piedras Blancas 0-10 nm
GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm
GLW...Pt Arena to Pt Reyes 0-10 nm
GLW...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Mry Bay
&&
PUBLIC FORECAST: Blier
AVIATION/MARINE: Canepa
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www.youtube.com/nwsbayareaThe San Francisco radar (KMUX), 46 km away, was scanning. The volume nearest the first event began at 09:45 UTC.
1 thunderstorm wind. Local standard time, as filed.
A tree fell on a house in the early morning in Atherton. A pine tree fell through the roof and into a bedroom. No injuries https://www.sfgate.com/news/bayarea/article/Nobody-Injured-Christmas-Morning-After-Tree-Falls-13490931.php.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2018Every state in 2018This day in weather historyWarnings in California, December 2018
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: 791931.