Persistent cold pattern caused several mornings of near and sub-freezing temperatures around the Bay Area and Central Coast. This was the second major cold event of the season and the most widespread.
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.
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.
Persistent cold pattern caused several mornings of near and sub-freezing temperatures around the Bay Area and Central Coast. This was the second major cold event of the season and the most widespread. Freeze Warnings were issued for the North Bay interior valleys from Dec 12-16, other interior valley and mountain zones from Dec 13-16, with Frost Advisories for coastal zones Dec 13-16.
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 12, 9:45 PM PST, 2 hours 15 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
945 PM PST Mon Dec 12 2022
.SYNOPSIS...Dry weather conditions and colder temperatures this
week. Inland frost and sub-freezing temperatures across the
interior valleys expected each morning.
&&
.DISCUSSION...as of 08:55 PM PST Monday...The sun set under
mostly sunny skies with a few fair weather cumulus clouds hugging
the hills. Despite some afternoon sunshine temperatures struggled
today. Maximum temperatures topped out in the 50s most areas with
30s and 40s over the higher elevations. Definitely below normal
temperatures for mid December.
The recent stormy weather is old news as high pressure begins to
build over the region. The wet weather may have ended, but the
cold temperatures will remain. Latest 24 hour temperature trend
this evening shows many spots already running 4-8 degrees colder
than last evening. In fact, part of the North Bay is already in
the 30s. Given the relatively clear skies, cold airmass, and light
winds temperatures tonight will be the coldest of the last few
nights. A Freeze Warning remains in effect for the interior North
Bay Valleys (see below for more details). Also see some fog
develop over the interior valleys. Freezing fog will also be
possible by morning.
Dry conditions continue, but so do the cold temperatures both day
and night. Below normal temperatures are in the official forecast.
Pretty remarkable to look at the ECMWF EFI see both TMAX and TMIN
below normal through 180 hours. Given the forecast a Freeze
Warning may be needed again Tuesday night into Wednesday with a
little more coverage.
No update need to near term forecast...
&&
.PREV DISCUSSION...as of 02:05 PM PST Monday...Dry weather conditions
have returned to the Bay Area and Central Coast as the mid/upper
level system that brought widespread wind and rain to the region
exits. That said, the northwest flow aloft and residual moisture
has allowed for scattered clouds to develop region-wide.
Conditions will begin to clear out late tonight and winds will
become light. This and the cold air mass that has settled into the
region will support much colder surface temperatures beginning
tonight. Most inland areas will cool into the 30s with the
region's coldest interior valleys bottoming out in the mid/upper
20s, especially across Sonoma and Napa counties. As such, a Freeze
Warning is in effect from 1 AM - 9 AM PST Tuesday for the
Interior North Bay Valleys. Mid/upper 30s to near 40 will be
common even near the coast. These temperatures will be hazardous
to unsheltered or marginally sheltered populations. Remember to
protect people, pets, plants, and pipes from the cold. Meanwhile,
day time temperatures will warm into the low to mid 50s for most
urban areas while upper 30s to 40s will persist in the mountains.
This cold pattern is likely to persist through much of the week as a
short-wave ridge builds over the region. Given little change in the
mid/upper level pattern through the week, expect the same with the
weather. Cool days, chilly to cold nights/mornings and dry weather
conditions. Confidence has increased with respect to maintaining dry
weather through late week as the deterministic models and their
ensembles are in better alignment.
It's now not until late in the weekend or early next week when the
National Blend of Models bring a slight chance of precipitation back
to the region. This would be in response to a weak short-wave trough
over the eastern Pacific approaching central or southern California.
That said, this system would have limited moisture to work with and
thus, any rainfall would be light. Again, all of this is low
confidence with a greater potential for dry weather to prevail
through the next 7 days. This corresponds well with the Climate
Prediction Center's 6-10 and 8-14 day outlooks favoring below normal
precipitation and temperatures heading into late December.
&&
.AVIATION...As of 09:45 PM Monday...For the 06Z TAFs. VFR with
low/mid level clouds scattering out this evening as light offshore
flow has kicked in. Light offshore flow will continue through the
night into the early afternoon Tuesday, helping to keep terminals
clear. KSTS will continue still see intermittent fog (IFR- LIFR
conditions) tonight despite light north- northeasterly winds
tonight. Light to moderate (8 to 12 knots) onshore winds return
Tuesday afternoon.
Vicinity of SFO...Winds have diminished and will continue to be
light and offshore through the night into the morning. Light NE
winds will help keep the SF Bay VFR and increasing confidence that
patchy low clouds will not form overnight over the Bay. Moderate
NW winds will resume late in the afternoon Tuesday before
diminishing again overnight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR with some lingering SCT-BKN clouds
around 4000 feet. As light drainage (SE) flow kicks in tonight,
these clouds will continue to scatter out. VFR will prevail
through the TAF period. Winds will shift back to NW Tuesday
afternoon and will generally be under 10 knots.
&&
.MARINE...as of 08:20 PM PST Monday...Breezy north-northwest
winds will continue through tonight but will diminish into the
morning. Sea state remains hazardous for small craft with wave
heights around 8 to 12 feet at 11 to 13 seconds. Northwest swell
will continue to diminish through midweek, with a new northwest
swell arriving Wednesday afternoon.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...Freeze Warning...CAZ506
SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM
SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM
SCA...Pt Arena to Pigeon Pt 10-60 nm until 3 AM
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM
&&
PUBLIC FORECAST: MM/RGass
AVIATION: McCorkle
MARINE: McCorkle
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www.youtube.com/nwsbayareaThe national radar mosaic for the moment the first event began.
1 cold/wind chill. Local standard time, as filed.
Six unhoused residents died from cold-related illness between the 13th and 14th. Four of those were in San Jose aged 40s-70s, with two others in unspecified areas in Santa Clara county.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Cold/Wind Chill, Santa Clara Valley Including San Jose | 2022-12-14 | Male | Unknown | Direct | |
| Cold/Wind Chill, Santa Clara Valley Including San Jose | 2022-12-14 | Male | Unknown | Direct | |
| Cold/Wind Chill, Santa Clara Valley Including San Jose | 2022-12-14 | Male | Unknown | Direct | |
| Cold/Wind Chill, Santa Clara Valley Including San Jose | 2022-12-14 | Male | Unknown | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, December 2022
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: 1073379.