A series of low pressure systems from the north and northwest, plus a weak tap into atmospheric river moisture, brought rain, mountain snow, and gusty winds to Southern California. Snow levels reached as low as 2000 feet, and brought high impact snow to locations above 4000 feet.
Every event with a place to put it; 6 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 SGX wrote it up.
A series of low pressure systems from the north and northwest, plus a weak tap into atmospheric river moisture, brought rain, mountain snow, and gusty winds to Southern California. Snow levels reached as low as 2000 feet, and brought high impact snow to locations above 4000 feet. Both I-8 through the San Diego Mountains and I-15 through the Cajon Pass were closed due to heavy snowfall. Between December 22-24, the coastal areas received 1-1.5 inches of rainfall, the valleys received 0.50-1 inch, and the mountain areas received up to 1 inch of rainfall. Again on December 26 through 27, coast and valley areas received 1 to 1.5 inches. Mountain areas received up to an inch. There were many water rescues, particularly in the Tijuana River Valley due to individuals driving through flooded roads and getting stuck. The San Diego River at Fashion Valley reached 10.5 feet on December 26.
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 21, 9:20 PM PST, 2 hours 40 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
920 PM PST Sat Dec 21 2019
.SYNOPSIS...
Upper level high pressure over Southern California will shift
east Sunday as an upper level trough moves in from the northwest.
This trough will establish itself over the U.S. West Coast next
week, sending Pacific storms into the area. One storm will impact
the area late Sunday and Monday, with a colder storm arriving
Christmas night through Thursday. Light precipitation is forecast
between these storms. Precipitation will come to an end Friday
with dry weather next weekend.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Weak offshore flow is ongoing this evening with windy conditions
mainly confined to the Inland Empire below the San Gorgonio Pass.
Ridgetop winds are already shifting to the south-southeast. This
trend will continue overnight with stronger south winds developing
along the ridges and desert slopes of the San Bernardino
Mountains. A Wind Advisory remains in effect for this area from 10
PM this evening through 10 PM Monday. Otherwise fair conditions
with plenty of high clouds around.
The main update this evening was to adjust the timing of both
storm systems. The first one looks like it will hold off until
early Monday morning and be slow to move inland. Based on the
trajectory of the short wave trough, the coastal areas and south
facing slopes of the San Bernardino Mountains may end up with the
highest precipitation totals, at least with the main rain band.
There is a slight chance of thunderstorms Monday afternoon and
evening as colder air aloft moves over, which could produce
locally higher rainfall amounts. Additional showers will follow
for Monday night into Tuesday over and west of the mountains.
Rainfall amounts will generally be around 0.75-1.25 inches from
the coast to the mountains, with locally higher amounts possible,
and 0.20-0.40 inches for the deserts.
The snow level will be around 5500-6000 ft most of the day Monday,
falling to around 5000 ft on Tuesday. 2-5 inches are possible
between 5500-6000 ft, and 5-10 inches above 6000 ft. Generally an
inch or less will fall below 5500 ft.
The forecast details become a little more dicey for Christmas Day
and Thursday as model solutions continue to fluctuate. A weak wave
may bring a brief increase in activity Christmas Day, but all
models and ensembles aside from the 00Z GFS shows little
precipitation. At this time kept precip amounts low for Wednesday.
Things don't get any better for Thursday as the EC keeps the upper
low further off the coast and digs it way south, denying us of the
main rain band. However, the ensemble mean is more in line with
the rest of the guidance. Even so, this system doesn't look quite
as wet as the first, at least west of the mountains. However, wrap
around moisture could play a role in more significant
precipitation for the deserts and be a good snow producer for the
Big Bear area. Depending on how it tracks, the Mojave Desert could
even get some snow Thursday night into Friday morning, though just
a dusting. Details of rain/snow amounts are definitely uncertain
with this system.
Offshore flow and drier weather follows for the remainder of the
day Friday into the weekend.
&&
.AVIATION...
220430Z...BKN-OVC high clouds at/above 20000 feet and unrestricted
vis will prevail through Sun evening. Some SCT-BKN clouds with bases
2000-3000 ft MSL are possible near the coast Sun afternoon and
evening. Rain will develop after 08Z Monday along the Orange County
coast.
&&
.MARINE...
A brief increase in south to southeast winds is expected late Sunday
night and early Monday morning ahead of a cold front, with peak wind
gusts around 20 kts over the coastal waters. Winds will shift to the
west and weaken quickly after the frontal passage Monday morning.
Winds may increase again midweek as another storm moves through,
though timing and wind strength are still uncertain. Precipitation
is likely at times late Sunday night through Thursday, heaviest on
Monday.
&&
.BEACHES...
14-15 second swells from 280-290 degrees will continue somewhat
elevated surf, mainly in San Diego County through Sunday. Surf will
mainly be 3-5 ft with local sets to 6 ft in San Diego County, but
mostly 2-4 ft in Orange County. Surf will lower slightly Monday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Weather Advisory from 10 PM Sunday to 4 AM PST Tuesday
for San Bernardino County Mountains.
Wind Advisory until 10 PM PST Sunday for San Bernardino County
Mountains.
PZ...NONE.
&&
PUBLIC...SS
AVIATION/MARINE/BEACHES...MaxwellThe national radar mosaic for the moment the first event began.
3 heavy snow, 2 heavy rain, 2 winter weather, 2 flood, 1 strong wind. Local standard time, as filed.
Many locations across coastal San Diego County reported 1 to 1.5 inches of precipitation (2-day storm total) from December 22 through 24.
Total snow from December 22 through 24 in the San Bernardino Mountains: Angelus Oaks 6 inches, Mountain Pass 1 foot, Arrowhead 25 inches, Big Bear City 3 feet, Wrightwood 8 inches, Top of Cajon Pass 2 inches.
Idyllwild received 3 inches of snow between December 22 and 24.
Total snow accumulation on December 26 in the San Bernardino Mountains: Mountain High 30-36 inches, Wrightwood 22-26 inches, Mt. Baldy (base of mountain) 28 inches, Big Bear Snow Summit 18-26 inches, Snow Valley 18-22 inches, Lake Arrowhead 16 inches. I-15 through the Cajon Pass was closed on December 26th due to heavy snow.
Phelan received 13 inches of snow. Victorville, Apple Valley and Hesperia received 2 to 4 inches of snow.
Total snow accumulation December 26 and 27 in the San Diego County mountains: Mount Laguna 12 inches and Palomar Mtn (Birch Hill) 10 inches. Interstate 8 was closed on December 26th due to heavy snowfall.
San Diego County coastal areas and valley areas received 1 to 1.5 inches between December 26 and 27. The mountain areas received up to 1 inch. There were many reports of water rescues, especially along the coast. The San Diego River at Fashion Valley reached 10.5 feet on December 26th.
Many downed trees in National City due to strong winds and a tree fell on top of a vehicle. Winds nearby were around 45 mph.
Flooding in San Marcos due to heavy rain.
A delivery driver was stranded in flood waters near the Mexico border, requiring rescue by a horse.
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: 870463, 870465, 870470, 870468, 870469, 870471, 870477, 870474, 870575, 870576.