Cold overnight temperatures into Christmas morning in the low to mid 40s across Santa Clara County caused two cold exposure deaths around San Jose.
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.
Cold overnight temperatures into Christmas morning in the low to mid 40s across Santa Clara County caused two cold exposure deaths around San Jose.
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 25, 4:15 AM PST, 45 minutes earlier.
Area Forecast Discussion
National Weather Service San Francisco Bay Area
415 AM PST Tue Dec 25 2018
.SYNOPSIS...A few showers may linger across the southern portion
of the region through mid morning. Otherwise, expect mostly sunny
skies today with temperatures near seasonal averages. Dry
conditions, generally clear skies, and seasonably cool
temperatures are then forecast to continue through the remainder
of the week, along with gusty winds at times. Slight rain chances
develop over the upcoming weekend.
&&
.DISCUSSION...As of 3:30 AM PST Tuesday...KMUX radar currently
shows scattered shower activity continuing across the eastern
portions of Alameda and Santa Clara Counties, as well as much of
Monterey and San Benito Counties. Showers are moving quickly to
the southeast and are expected to end in most areas by daybreak.
However, the latest HRRR forecast a few showers lingering across
southern Monterey County and southern San Benito County until a
few hours after sunrise. Thereafter, expect dry conditions for the
remainder of Christmas day, as well as clearing skies from north
to south. Seasonably cool temperatures are expected today with
highs mostly in the upper 50s. Brisk northwest winds are expected
to subside in most areas by daybreak.
Dry conditions are forecast to persist through the remainder of
the week as our region will be under dry northerly flow between an
upper ridge over the eastern Pacific and a deep trough to our east
over the Intermountain West. A shortwave trough is forecast to
ride over the ridge on Wednesday and Wednesday night and dig
south into the Great Basin by Thursday morning. This "inside
slider" system will bring a reinforcing shot of cool air into our
area and also generate gusty northerly winds on Thursday and
Thursday night. Winds will be strongest in the hills where gusts
up to 40 mph, or locally higher, are possible. Locally blustery
conditions are also possible near sea level on Thursday.
Daytime temperatures are not expected to change much through the
week, except perhaps cool slightly after midweek. Nighttime
temperatures will trend lower through the week, with the coolest
nights expected to be Thursday night and Friday night. Winds on
Thursday night should help hold temps up a bit, except in wind
sheltered valleys where areas of late night and early morning
frost are expected. More widespread inland valley frost is likely
late Friday night and early Saturday when winds will be lighter
and overnight lows will drop as low as the upper 20s in the
coldest valleys.
Both the GFS and ECMWF indicate a weak system will arrive from the
northwest by late in the weekend, possibly generating some light
precipitation by Saturday night or Sunday.
&&
.AVIATION....as of 3:50 AM PST Tuesday...Showers have all but come
to an end across area terminals. Improving sky conditions expected
as the low slides farther south. Lingering MVFR cigs expected this
morning in the wake of the cold front with clear skies expected by
this afternoon. Moderately gusty winds will continue through this
morning and locally through this afternoon. Winds will gradually
ease this afternoon and evening.
Vicinity of KSFO...VFR to MVFR cigs expected this morning in the
wake of the cold front. Clear skies expected by this afternoon.
Moderately gusty winds will continue through this afternoon then
will gradually ease this evening.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...VFR to MVFR cigs expected this morning in the
wake of the cold front. Clear skies expected by this afternoon.
Moderately gusty winds will gradually ease by this evening.
&&
.MARINE...as of 2:54 AM PST Tuesday...A low pressure system
sliding south along the coast will maintain gale force gusts
across the coastal waters this morning. As the cold front moves
south showers will come to an end. Gusty northerly winds and fresh
swells will continue Wednesday through Friday as high pressure
builds and a strong pressure gradients set up near Cape Mendocino.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tday...GLW...Pigeon Pt to Pt Pinos 0-10 nm until 9 AM
GLW...Pt Arena to Pigeon Pt 10-60 nm until 9 AM
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 until 3 PM
GLW...Pt Reyes to Pigeon Pt 0-10 nm until 3 PM
SCA...Mry Bay
&&
PUBLIC FORECAST: Dykema
AVIATION/MARINE: CW
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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.
The Medical Examiner out of Santa Clara county reported two fatalities believed to be caused by cold exposure around San Jose. Time is estimated.
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 | 2018-12-25 | Outside/Open Areas | Direct | ||
| Cold/Wind Chill, Santa Clara Valley Including San Jose | 2018-12-25 | Male | Outside/Open Areas | Direct |
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: 791367.