An upper level low moved through Southern California on January 31st and brought heavy rain and thunderstorms to the region. Thunderstorms brought occasional heavy precipitation, resulting in flash flooding.
Every event with a place to put it. 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.
An upper level low moved through Southern California on January 31st and brought heavy rain and thunderstorms to the region. Thunderstorms brought occasional heavy precipitation, resulting in flash flooding. The coastal areas of Orange and San Diego County received a half an inch of precipitation over 2 hours. The Pacific Coast Highway (Highway 1) was closed due to flooding. Lightning struck a tree and damaged a fence in San Diego County. 40 cloud-to-ground strikes were observed in San Diego County.
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 Jan 31, 9:30 AM PST, 3 hours 30 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
930 AM PST Thu Jan 31 2019
.SYNOPSIS...
A fast-moving low pressure system from the northwest will bring
showers from late morning through early evening with a slight chance
of thunderstorms. Locally heavy rain will occur. Friday will be dry
but cool. A larger stronger storm will bring widespread rain, with
heavy rain on south-facing mountain slopes late Friday night and
Saturday. After the frontal passage late Saturday, some snow will
fall in the mountains. Low pressure continuing to the north will
bring occasional showers Sunday through Tuesday with fair weather
returning by Wednesday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Showers and thunderstorms had spread east into LA County and should
spread into northwestern Orange County around 1030 AM. Latest HRRR
and WRF show the debris flow threat to the Holy Fire burn scar
beginning around 1 PM. Both models show some locations receiving
1/2" of rain or more, with areal 12-hour totals averaging around 1".
Due to the convective nature of the precip, the differences between
the mountains and the coast will be minimal. Snow levels will mostly
be above 7000 feet with this system.
Friday should have quite a bit of cloud cover but should be
precipitation-free being between systems. The Saturday system will
have an atmospheric river and that will combine with strong
orographics in the low-level saturated south-southwest flow to bring
heavy amounts of precip on the south/southwest facing mountain
slopes. A few light showers could start as early as late Friday
night, but the main orographic precip will occur Saturday, then the
frontal passage combined with favorable jet stream dynamics likely
will bring a period of heavy precip at lower elevations as well late
Saturday afternoon/early Saturday evening. Saturday rainfall will
likely be 1 inch or more in most areas except the deserts, but some
south slopes in SBD could get 5-8 inches. Snow levels should be
quite high Saturday, probably at/above 8000 feet, then lower to 5000-
6000 feet after frontal passage, and moisture could remain deep
enough (to over 10000 feet MSL) in the WSW flow for substantial
mountain snows, especially in San Bernardino County. There could be
6 or more inches of snow Saturday night/Sunday in the SBD County
mountains.
Onshore flow and continuous moisture to 800-700 MB should continue
showers Sunday wiht another strong upper low progged to move through
mainly northern/central California Monday into Tuesday. As we will
be on the south side of this storm with a weaker surface low, the
precip amounts will be considerably lower than Saturday. Fair
weather likely will return Wednesday, with a ridge developing off
the coast.
&&
.AVIATION...
311630Z...Coast to Mountains: Areas of low clouds west of the mtns,
with bases around 1500 feet msl and tops to 3000 feet. Areas of
inland vis 2-5 miles. Low clouds increasing in coverage during the
day with showers between 18-02Z. Cigs/vis reduced in rain and fog,
with higher terrain obscured. After 04Z cigs will lift to 2000-3000
feet with SCT low clouds lingering overnight. Confidence in low cigs
at TAF sites is low after 04Z.
Deserts: Variable clouds AOA 12000 feet. Lower clouds with bases
3000-5000 feet and showers between 22-04Z. Clearing after 04Z.
&&
.MARINE...
South winds today with isolated gusts over 20 knots. Showers and a
slight chance of thunderstorms this afternoon. A frontal passage
will produce a sharp wind shift from southerly to westerly during
the afternoon. A more substantial storm system Friday night and
Saturday will bring stronger winds approaching gale force and larger
swell. Winds will decrease Sunday, but swell will peak then,
possibly creating hazardous seas.
&&
.BEACHES...
A winter storm will bring the potential for lightning at the beaches
this afternoon.
&&
.SKYWARN...
Skywarn activation will be needed beginning at noon.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Flash Flood Watch from 10 AM PST this morning through this
afternoon for Santa Ana Mountains and Foothills.
PZ...NONE.
&&
PUBLIC...Maxwell
AVIATION/MARINE/BEACHES...PGPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO CA
1224 PM PST THU JAN 31 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1213 PM FLOOD 1 NE NEWPORT BEACH 33.62N 117.91W
01/31/2019 ORANGE CA PUBLIC
HEAVY RAIN/THUNDERSTORMS IN NEWPORT BEACH
AND COSTA MESA CAUSED URBAN STREET FLOODING.
&&
COThe San Diego radar (KNKX), 18 km away, was scanning. The volume nearest the first event began at 21:00 UTC.
1 lightning, 1 heavy rain. Local standard time, as filed.
Broadcast media reported that lightning struck a fence and caused damage to it. 40 cloud-to-ground lightning strikes were observed during this event.
CalTrans reported Pacific Coast Highway (highway 1) closed due to flooding. This area received around 0.5 inch of rainfall in 2 hours.
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, January 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: 805148, 805149.