A long-period west-northwest swell moved into Southern California on December 17th and continued through the 19th. Sets of 6-9 ft were observed in Orange and San Diego County on Friday the 18th.
Every event with a place to put it; 2 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 long-period west-northwest swell moved into Southern California on December 17th and continued through the 19th. Sets of 6-9 ft were observed in Orange and San Diego County on Friday the 18th. Ocean Beach Pier in San Diego County was closed due to the high surf.
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 16, 9:41 PM PST, 2 hours 19 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
941 PM PST Sun Dec 16 2018
.SYNOPSIS...
The tail end of a storm system moving across Northern California
tonight will reach Southern California on Monday. There is just a
slight chance of light showers along and west of the mountains
Monday afternoon through Monday night as this storm weakens. A
strong ridge will build into the region behind this system the
trough with fair and much warmer weather Wednesday through Friday.
The ridge will break down over the weekend as storms pass by well to
the north. This will lead to slight cooling, but a continuation of
dry conditions is expected through next weekend. High surf will
pound the beaches Monday and Tuesday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Evening Update:
No major changes were made to the forecast this evening. The tail
end of a weakening Pacific storm system will bring a few sprinkles
late tonight and Monday morning with a slight chance of showers
Monday afternoon through Monday evening. Gradients are transitioning
to onshore attm and areas of low clouds have developed along the
coast and in the inland valleys. The previous forecaster discussion
remains valid below.
Highlights:
* Tail end of weakening storm brings slight chc showers Monday
* Warm, dry weather rest of the week with peak warmth midweek
* High surf to pound the beaches Monday-Tuesday along with small
craft advisory conditions over the outer coastal waters
A tranquil and mainly dry weather pattern will prevail through next
weekend.
A storm system is moving into NorCal this evening and will continue
to move southeast with the tail end reaching SoCal on Monday.
Moisture transport will be dwindling and as such will maintain just
a slight chance of showers in the forecast Monday afternoon through
early Tuesday morning.
Behind this system will be an expansive, anomalous upper ridge
building over Baja and into Southern California (NAEFS return
interval at 5-10 year) with the ridge axis fully over the area on
Thursday when H5 heights peak to around 588 DM. The result will be
temps going from above average to MUCH above average Wed-Fri with
80s common inland on Thursday (except of course in the mountains as
well as across the high desert).
The ridge will break down as storm systems pass by well to the north
this weekend. This will lead to some cooling, but temps will remain
running above average. Dry weather will prevail.
Early next is favoring a dry scenario with an inside upper trough
scenario. This is portrayed in the operational GFS run as well as
the GEFS. However, the latest operational run of the ECMWF shows a
closed low diving southward and right over SoCal on Christmas Day,
but with low QPF. So while we can't discount that scenario, favoring
a dry one at this time.
&&
.AVIATION...
170500Z...Coast/Valleys...Areas of BKN-OVC stratus, with bases 1000-
1600 ft MSL and tops near 2000 ft MSL, will continue to develop
within 15-25 miles of the coast tonight. VIS of 2-4 SM BR is
expected where low clouds near higher terrain. Otherwise, high
clouds above 20000 feet MSL will increase tonight with some mid-
level clouds between 5000 and 10000 feet MSL increasing Monday.
Mountains/Deserts...High clouds above 20000 feet MSL with
unrestricted vis will prevail through tonight, with an increase in
clouds at various height levels and possible local mountain
obscurations Monday. There is a small chance of very light showers
late Monday.
&&
.MARINE...
A large WNW swell Monday and Tuesday will generate combined seas of
10-13 feet in the outer coastal waters. Swell and seas will lower
Wednesday, but another WNW swell could bring seas near 10 feet in
the outer coastal water Thursday. A Small Craft Advisory for
Hazardous Seas has been issued.
&&
.BEACHES...
A High Surf Advisory remains in effect Monday morning through
Tuesday evening. A west northwest swell of 10-13 ft in the outer
waters with a period of 18-20 sec from 290 degrees will impact the
area Monday and Tuesday. Surf of 6-11 feet is likely with sets to 13
ft possible, highest south of Del Mar. Strong rip currents and
dangerous swimming conditions at all beaches. Swell and surf will
gradually lower on Wednesday, though another large swell could again
bring elevated surf Thursday or Friday.
&&
.SKYWARN...
Skywarn activation will not be needed.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory from 8 AM Monday to 10 PM PST Tuesday for
Orange County Coastal Areas-San Diego County Coastal Areas.
PZ...Small Craft Advisory for hazardous seas from 9 AM Monday to noon
PST Tuesday for Waters from San Mateo point to the Mexican
Border Extending 30 to 60 nm out including San Clemente
Island.
&&
PUBLIC...Gregoria/JMB
AVIATION/MARINE/BEACHES...JJTThe national radar mosaic for the moment the first event began.
2 high surf. Local standard time, as filed.
Lifeguards at Mission Beach and Solana Beach reported 6-8 ft surf on December 17th and 18th.
Lifeguards at Huntington Beach reported 6-8 ft surf December 17th and 18th.
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: 798904, 798905.