Heavy Snow and High Wind in California, December 23 to 24, 2016

Name: Heavy Snow and High Wind in California, December 23 to 24, 2016
Start: 2016-12-23T20:00
End: 2016-12-24T22:51
Location: California

December 23 to 24, 2016 · NWS SGX · 8 events in 6 counties and zones

A cold upper level trough and Pacific front traversed the region on the 23rd and 24th of December. The heaviest precipitation fell from the evening of the 23rd through the morning of the 24th.

Where it happened

Every event with a place to put it; 8 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $10,000
Crop damage: None recorded
Events: 8

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.

What happened

The episode as NWS SGX wrote it up.

A cold upper level trough and Pacific front traversed the region on the 23rd and 24th of December. The heaviest precipitation fell from the evening of the 23rd through the morning of the 24th. Snowfall lingered through the 24th in the San Bernardino County Mountains. Snow was the main impact with snow levels as low as 3,500 ft, and accumulations of close to 2 ft on the highest peaks in the San Bernardino County Mountains. Rainfall totals ranged from 0.50 inches at the coast to 2.00 inches along the coastal slopes. Gusty winds also impacted the mountains and desert slopes.

What forecasters said that day

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 Diego, CA wrote its last area forecast discussion before the first event at Dec 23, 2:00 PM PST, 6 hours earlier.

Area forecast discussion, Dec 23, 2:00 PM PST, 6 hours before

Area Forecast Discussion
National Weather Service San Diego CA
200 PM PST Fri Dec 23 2016

...Strong winter storm system tonight and Saturday...

.SYNOPSIS...
Cloudy skies with a few showers and areas of mountain fog will
continue this afternoon. A strong cold storm system will move through
southern California tonight and Saturday and bring moderate to heavy
rainfall with snow in the mountains. Strong gusty winds will occur
mainly in the mountains and deserts this afternoon through Saturday,
but somewhat strong winds will occur at the coast as well. Partly
cloudy but cool weather will return Sunday with a slow warming trend
likely for the early to middle part of next week. An upper level low
could bring showers Thursday night or Friday.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Widespread clouds with a few showers and mountain fog were occurring
this afternoon. The center of the upcoming trough is currently about
300 miles west of Point Conception, and rain is occurring across a
lot of central California with showers ahead of the system moving
through Santa Barbara and Ventura Counties. With saturation already
in place to 800 MB, precip should be easy to start when the
dynamics of the storm arrives. The onset of significant precip
should be around 6 PM in NW Orange County and by 1 AM over the
mountains and into the deserts of San Diego County. Rainfall amounts
still look to be one to locally two inches west of the mountains with
local 2-3 inch totals in the mountains. Since moisture extends to
above 500 MB with the front, some of the precip will extend into the
deserts, with around 1/4 inch in the lower deserts and 1/2 inch in
the high deserts. With the front, rainfall rates could reach or even
exceed 1/2 inch per hour. Also, with 500 mb temps below -25 deg C
Saturday, there could be a few thunderstorms with brief heavy
rainfall. The snow level will fall from about 6500 feet with the
onset of the precip this evening to 4000 feet by Saturday morning and
3000 feet by late Saturday with the colder air moving in. With
moisture at times above the -10 C level, dendritic snow crystals
could form to increase snowfall amounts in the mountains. Overall,
expect about a foot, locally higher above 7000 feet, 8-12 inches in
the 5500-6000 foot levels and up to 4 inches around 4000 feet through
early Saturday night. Expect strong winds at time in the mountains
and deserts, with the focus on San Bernardino County through late
evening with the southerly flow and then gradually Riverside and San
Diego Counties late tonight and Saturday as the flow becomes more
westerly. Local gusts over 70 MPH will be possible, mainly from the
mountain crests north and east to the desert mountain slopes.

After this storm moves east, a closed low dives south off the
California coast and to a point around 600 miles to our west Monday.
The 12Z ECMWF now agrees with GFS and Canadian models with having
the upper low to our southwest until Thursday, which would mean we
would have offshore flow and dry weather. Most model solutions,
including the 12Z ECMWF, has the low moving somewhere near San Diego
Friday with some showers possible. Timing is low-confidence due to
this being a cut-off low, and if the low ends up further north than
expected, precip could be more substantial. There should be a
gradual warming trend next week after a chilly start, partly due to
offshore flow, which could bring temps back bear 70 west of the
mountains by around Tue or Wed.

&&

.AVIATION...
232125Z...Multiple SCT-BKN cloud layers with bases 1000-3500 ft MSL
and tops to 6000 ft MSL will continue through the day. A pacific
storm will bring widespread precipitation between 23/03-12Z, with
scattered showers and possible thunderstorms 23/12-24/00Z. Local
CIGS as low as 500 ft MSL and vis 2 SM or less in heavier
showers/thunderstorms. Higher terrain will remain obscured in
clouds/fog/precip through late Saturday.

Gusty south winds developing ahead of the front this afternoon and
evening. Surface gusts 45-55 kt possible over the ridges, desert
mountain slopes, and desert foothills, strongest in San Bernardino
County. STG-SVR UDDFS and LLWS likely over and N/NE of the mountains.

&&

.MARINE...
A stronger Pacific storm moving in from the northwest will bring
heavier showers, possible thunderstorms, strong gusty WNW winds, and
large, rough seas late this evening through early Sunday. Conditions
will improve during the day Sunday. A larger WNW swell will move
into the coastal waters tonight as well, building to 8 to 10 feet
Saturday. The winds and swell will combine to create hazardous seas
and boating conditions. A small craft advisory is in effect for
those conditions...see LAXMWWSGX for details.

&&

.BEACHES...
There is a small chance of thunderstorms at the beaches Saturday
morning through Saturday afternoon as another storm system moves
through the region. Elevated surf and strong rip currents are also
possible Saturday into early Sunday.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 10 PM PST Saturday for Apple
     and Lucerne Valleys-Riverside County Mountains-San
     Bernardino County Mountains-San Diego County Deserts-San
     Diego County Mountains-San Gorgonio Pass Near Banning.

     Winter Storm Warning from 10 PM this evening to 3 AM PST Sunday
     for Riverside County Mountains-San Diego County Mountains.

     Winter Storm Warning from 6 PM this evening to noon PST Saturday
     for San Bernardino County Mountains.

     Flash Flood Watch from this evening through late tonight for San
     Bernardino County Mountains.

PZ...Small Craft Advisory from 4 PM this afternoon to 4 AM PST Sunday
     for Coastal Waters from San Mateo Point to the Mexican
     Border and out to 30 nm-Waters from San Mateo point to the
     Mexican Border Extending 30 to 60 nm out including San
     Clemente Island.

&&

PUBLIC...Maxwell
AVIATION/MARINE/BEACHES...TS

In the hours before

Local storm report, Dec 23, 7:29 PM PST, 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
729 PM PST FRI DEC 23 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0545 PM     NON-TSTM WND GST 5 ENE GEORGE AFB        34.61N 117.29W
12/23/2016  M51 MPH          SAN BERNARDINO     CA   MESONET

            MESONET STATION VICTORVILLE (5 N) /GHG39/.

&&

NWS SAN DIEGO CA
IRIS SYSTEM

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 strong wind, 2 heavy snow, 2 high wind, 1 winter weather. Local standard time, as filed.

Heavy Snow, San Bernardino County Mountains

When: December 23, 8:00 PM PST to December 24, 6:00 PM PST
Where: San Bernardino County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

Multiple spotters reported 12 hour snowfall totals of 18 inches in Big Bear between 2100PST on the 23rd and 0900PST on the 24th. Other 12 hour totals in the San Bernardino County Mountains included 18 inches near Green Valley Lake, 12 inches in Forest Falls, 11 inches in Wrightwood, and 10 inches in Lake Arrowhead.

Strong Wind, San Diego County Valleys

When: December 23, 9:30 PM PST to 11:30 PM PST
Where: San Diego County Valleys forecast zone
Measured: 35 kt (40 mph) estimated gust
Property damage: $3,000
Reported by: Trained Spotter
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

A large tree downed by winds blocked the road near the intersection of Rancho Bernardo Rd. and Alva Rd. Peak gusts in the area were near 40 mph, with most gusts in the 25-35 mph range. This was the only significant damage report in the valleys.

Heavy Snow, Riverside County Mountains

When: December 23, 10:00 PM PST to December 24, 9:00 AM PST
Where: Riverside County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 33.744, -115.994 (the zone’s center; the record gives no point)

A spotter in Fern Valley reported an 11 hour snowfall total of 14 inches between 2200PST on the 23rd and 0900PST on the 24th. Another spotter reported 7 inches of snow in Idyllwild during this same period.

Winter Weather, San Diego County Mountains

When: December 23, 10:00 PM PST to December 24, 10:00 PM PST
Where: San Diego County Mountains forecast zone
Reported by: Trained Spotter
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

Spotters in Julian and at Mt. Laguna reported 10 hour snowfall totals of 6 inches between 2200PST on the 23rd and 0800PST on the 24th. During the same period 5 inches fell at Palomar Mountain, 2 inches in Guatay and 1 inch in Pine Valley.

Strong Wind, Orange County Coastal

When: December 24, 4:00 AM PST to 5:00 AM PST
Where: Orange County Coastal forecast zone
Measured: 35 kt (40 mph) estimated gust
Property damage: $5,000
Reported by: Trained Spotter
Coordinates: 33.677, -117.776 (the zone’s center; the record gives no point)

Several trees were downed near Orange Coast College in Costa Mesa. Winds in the area were predominantly gusting 25-35 mph with isolated gusts to 40 mph.

High Wind, San Diego County Mountains

When: December 24, 11:20 AM PST to 1:20 PM PST
Where: San Diego County Mountains forecast zone
Measured: 63 kt (72 mph) measured gust
Reported by: Mesonet
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

Winds at Volcan Mountain gusted in excess of 70 mph for 2 hours, with peak gust of 73 mph. Numerous other stations in the San Diego County Mountains gusted between 55 and 70 mph between 0800 and 1800PST on the 24th. No damage was reported.

Strong Wind, San Diego County Coastal Areas

When: December 24, 1:30 PM PST to 2:00 PM PST
Where: San Diego County Coastal Areas forecast zone
Measured: 35 kt (40 mph) estimated gust
Property damage: $2,000
Reported by: Law Enforcement
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

CHP reported a tree down along Sweetwater Rd. in Lemon Grove. Peak gusts in the area were near 40 mph, with most gusts in the 25-35 mph range. This was the only significant damage report along the coast.

High Wind, San Bernardino County Mountains

When: December 24, 8:51 PM PST to 10:51 PM PST
Where: San Bernardino County Mountains forecast zone
Measured: 70 kt (81 mph) measured gust
Reported by: Mesonet
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

The RAWS station in Burns Canyon measured wind gusts in excess of 70 mph for 2 hours, with a peak of 80 mph during a surfacing mountain wave. Other stations in the area measured gusts between 35 mph and 50 mph during the same period.

What these are

Heavy Snow: Snowfall reaching the local warning threshold without the other hazards of a winter storm.
Strong Wind: Non-thunderstorm winds below high wind criteria that nonetheless caused damage or casualties.
Winter Weather: Snow, sleet or freezing rain below warning levels that still caused disruption, damage or casualties.
High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2016 Every state in 2016 This day in weather history Warnings in California, December 2016

Sources

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: 670355, 670375, 670359, 670361, 670369, 670363, 670366, 670364.