A closed upper low from the Pacific Northwest dropped south into Southern California, bringing gusty north to northeast winds, rain, and mountain snow February 9-11. Peak wind gusts of 60-70 mph were observed in the wind prone passes and canyons on February 10th and 11th.
Every event with a place to put it; 17 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 closed upper low from the Pacific Northwest dropped south into Southern California, bringing gusty north to northeast winds, rain, and mountain snow February 9-11. Peak wind gusts of 60-70 mph were observed in the wind prone passes and canyons on February 10th and 11th. Many impacts occurred with these winds, including many overturned tractor trailers, trees downed, and flights diverted due to strong surface winds and wind shear. Rainfall totals ranged from a few tenths of an inch at the coast to up to 1 inch along the coastal slopes of the mountains. Up to 8 inches of snow fell in the San Bernardino Mountains, and up to 7 inches fell in the San Diego County mountains.
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 Feb 9, 5:06 AM PST, 2 hours 54 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
506 AM PST Sun Feb 9 2020
.SYNOPSIS...
An approaching storm system moving in from the north today will
bring showers and cool conditions to Southern California through
Monday night. The storm could bring significant snowfall to the
San Bernardino County mountains, especially in the Big Bear area.
Onshore winds will strengthen tonight, becoming offshore Sunday
through Tuesday as the storm moves to the southeast. Northwest
flow will prevail for the remainder of the week with near normal
temperatures, and another chance of light precipitation for next
weekend.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Key Points:
* Winter storm arrives from the north today, bringing impacts from
this afternoon through Monday night or Tuesday morning.
* Snowfall in the mountains will cause travel interruptions.
* Widespread mainly light to moderate rain for lower elevation
areas.
Wow whew what a doozy of a forecast this morning! Forecast
confidence in the overall track of the cutoff low and potential
for heavier precipitation has increased a bit due to better
consistency in the short term models. A developing closed low will
move into SoCal later today...which will eventually form out of
the vigorous trough over Eastern California attm. This system will
deepen through tonight and drop SSW across Socal later today,
passing over the LA Basin this evening, then dropping just west of
San Diego over the coastal waters tonight, then moving onshore
near or just south of Ensenada Baja California Monday.
The cutoff closed low pressure system will tap into some moisture
off the Pacific and spread wrap around precipitation into the
eastern slopes of the mountains tonight and Monday. With cold air
in place, this system will have the potential to produce heavy
snowfall in the San Bernardino Mountains, especially in the Big
Bear area, therefore the winter storm watch was upgraded to a
winter storm warning this morning. Areas above the snow level,
which will drop to between 3500 to 4000 feet tonight, will have
the potential to receive heavy snow, possibly around one foot or
even higher amounts in localized spots along the eastern slopes of
the San Bernardino Mountains, where around 15 inches could fall.
Winter Weather Advisories were also posted for the High Desert
where 1 to 2 inches of snow will be likely late tonight into
Monday, and in the San Diego and Riverside County Mountains, where
snow amounts will not be as high as in the San Bernardino
Mountains, but still likely to receive several inches of snow in
the higher mountains. Pass levels most likely to see snow will be
the Cajon Pass in the San Bernardino Mountains. Low confidence of
accumulating snow along Interstate 8 in San Diego County, as the
snow level will likely be very near the passes, nonetheless even a
light coating of snow along the interstate could be an impact to
travel.
The wrap around precipitation will diminish Monday afternoon, with
scattered showers continuing into Monday night, diminishing by
daybreak Tuesday morning, as the storm ejects eastwards towards
New Mexico during the day Tuesday.
Rainfall amounts have trended up a bit with this forecast, with
0.2 to 0.4 inches expected for most of the lower elevation areas,
and one-half to one inch in the mountains, especially along the
eastern slopes of the mountains due to wrap around precip.
NNE winds will develop as the low drops SW of our region late
tonight into Monday. There is still some concern for strong winds
along the slopes of the San Bernardino and Santa Ana Mountains on
Monday. Strong winds were included in the winter storm warning for
the San Bernardino Mountains with gusts around 50 mph possible,
and a wind advisory has been issued for the Northern Inland Empire
and Orange County, where wind gusts up to 40 mph will be
possible.
Quieter weather is still expected for Wednesday through Friday.
Another storm is still possible for next weekend, but ensemble
forecasts give very low forecast confidence at this point, and
deterministic forecasts are all over the map. The pattern favors
cool NW flow during this time which should keep temperatures from
rising above seasonal norms.
&&
.AVIATION...
090500Z...Coast/Valleys/Mountains...Deepening moisture
associated with an approaching frontal system tonight with cloud
bases near 2000 feet MSL, tops initially 2500 feet, will deepen to
exceed 3500 feet MSL by 15Z. Higher terrain becoming obscured in
clouds after 14z, with -SHRA developing around 16Z near the coast
and progressing eastward through the day. Strong southerly morning
will shift to easterly by 09Z early Monday morning as the frontal
system moves through. STG UDDFTS and LLWS can be expected Sunday
through Monday near mountains and adjacent mountain slopes as winds
increase to 20 to 30 knots with gusts approaching 50 knots at times.
Deserts...Clouds, showers, and deteriorating conditions reaching
into the deserts by around 00z Sunday afternoon and continuing into
Monday.
.MARINE...
A storm system will bring showers Sunday through Monday, but current
guidance suggests that the thunderstorm risk is now minimal.
Otherwise, no hazardous weather is expected through Wednesday.
&&
.MARINE...
A storm system will bring showers Sunday through Monday, but current
guidance suggests that the thunderstorm risk is now minimal.
Otherwise, no hazardous weather is expected through Wednesday.
&&
.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 this evening to 4 AM PST
Tuesday for Riverside County Mountains-San Diego County
Mountains.
Wind Advisory from 9 PM this evening to noon PST Monday for
Orange County Coastal Areas-Orange County Inland Areas-San
Bernardino and Riverside County Valleys-The Inland Empire-
Santa Ana Mountains and Foothills.
Winter Storm Warning from noon today to 4 AM PST Tuesday for San
Bernardino County Mountains.
Winter Weather Advisory from 6 PM this evening to 10 PM PST
Monday for Apple and Lucerne Valleys.
PZ...NONE.
&&
PUBLIC...Brotherton
AVIATION/MARINE...RodriguezThe national radar mosaic for the moment the first event began.
13 high wind, 3 strong wind, 1 heavy snow. Local standard time, as filed.
Spotters reported up to 8 inches of snow in Big Bear and up to 6 inches at Mountain High. A few inches of snow fell in Snow Valley, as well as Fawnskin.
Deer Canyon reported a peak wind gust of 56 knots between 0100 and 0200 PST on February 10th.
CalTrans reported a 100 foot tree down in Snow Valley due to high winds. This closed down Highway 18 near Snow Valley.
Fremont Canyon reported a peak wind gust of 50 knots between 0400 and 0500 PST on February 10th.
CalTrans reported a 2 ton semi truck overturned along the westbound I-210 and southbound I-15 connector. Road was closed through 1130 PST.
CSU San Bernardino reported a peak wind gust of 61 knots between 0600 and 0700 PST on February 10th.
A semi-truck was overturned in northbound I-15 in Fontana due to strong winds.
Multiple trees fell onto a car and a house, damaging them, in Yucaipa around 0200 PST on February 11th. Peak wind gusts were around 54 mph at the time.
Keen Ridge reported a peak wind gust of 54 knots between 0400 and 0500 PST on February 11th.
Peak wind gust at Ontario International Airport was 57 knots. Two commercial and one cargo flight were diverted to Los Angeles International Airport due to high winds.
Six semi-trucks were overturned near Ontario on the I-15 and I-10 connector. This closed down northbound I-15 at the connector.
Several trucks were overturned in Fontana on I-15 around 0630 PST. Peak wind gusts at the time were around 59 mph.
Lytle Creek reported a peak wind gust of 56 knots between 0600 and 0700 PST on February 11th.
Moreno Valley reported a peak wind gust of 58 knots between 0600 and 0700 PST on February 11th.
Case Springs reported a peak wind gust of 59 knots between 0600 and 0700 PST on February 11th.
Mt Laguna reported a peak wind gust of 50 knots between 0600 and 0700 PST on February 11th.
Devil Canyon reported a peak wind gust of 60 knots between 0800 and 0900 PST on February 11th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2020Every state in 2020This day in weather historyWarnings in California, February 2020
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: 879028, 879010, 879008, 879011, 878850, 879012, 879009, 879013, 879018, 879017, 879015, 879016, 879020, 879021, 879022, 879023, 879024.