A trough of low pressure moving down the West Coast brought strong winds to the mountains and deserts of Southern California on March 5th and 6th.
Every event with a place to put it; 3 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 trough of low pressure moving down the West Coast brought strong winds to the mountains and deserts of Southern California on March 5th and 6th.
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 Mar 5, 12:44 PM PST, 2 hours 7 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
1244 PM PST Sun Mar 5 2017
.SYNOPSIS...
A low pressure system and associated weak cold front moving
inland through the western states will bring cooling today with
periods of scattered light precipitation along and west of the
mountains. Stronger westerly flow will bring strong and gusty
winds to the mountain ridges, desert slopes and adjacent deserts
through late tonight. Dry with a warming trend for Monday through
Thursday with weak offshore flow and high temperatures for
Wednesday and Thursday well above average. Cooling for Friday
through next weekend as another trough of low pressure moves
toward the West Coast bringing onshore flow to Southern
California.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
On water vapor imagery, a trough can be seen moving inland over
northern California, with a cold front moving southeast through
Orange and San Bernardino counties as of 1230 pm. Radar imagery
shows scattered light showers associated with the cold front and
rain gages upstream where the front already moved through showed
amounts mainly less than a tenth of an inch with local amounts up
to 0.20-0.25 inches. The cold front and associated light
precipitation should move into western Riverside county around 1
pm, and then San Diego county between 3 and 4 pm. Scattered light
precipitation will continue in the early to mid evening and then
dissipate by late evening as the cold front moves east into
Imperial County. Total precipitation amounts look pretty light: a
trace to 0.15 inches in the coast and valleys, 0.05-0.25 inches in
the mountains, and mainly a trace in the deserts. Up to 2 inches
of snow is possible above around the 7000 foot elevation level
with a trace down to 6000 feet. The trough and increased cloud
cover is bringing temperatures 10-15 degrees lower than at this
time yesterday, and highs are expected to fall to 5-13 degrees
below normal today.
Currently, winds are starting to strengthen, with weather stations
in the High Deserts reporting gusts in the low 40 mph range and
locations in the desert slopes and in the San Gorgonio Pass
report winds gusting 45-60 mph. Onshore pressure gradients are
strengthening as well, with the San Diego to Las Vegas gradient
already up to 13.6 mb. Meanwhile, 850 mb westerly winds are
expected to increase to 25-30 kt. Hi-res models indicate very
strong winds along the desert slopes and the San Gorgonio Pass in
the late afternoon/early evening, with gusts of 70-80 mph
possible. It does not appear that winds this strong will surface
into the lower deserts, with gusts of 45-50 mph possible in those
areas. High Wind Warnings remain in effect for the mountains, high
deserts and San Gorgonio Pass/Northern Coachella Valley, and Wind
Advisories remain in effect for the rest of Coachella Valley and
the San Diego county deserts.
A warming trend should start Monday as an upper level ridge starts
to build into the region following the departing trough. In
addition, onshore flow weakens quickly and turns weakly offshore
during the day Monday. The ridge and weak offshore flow will
continue through Thursday, resulting in continued warming and fair
weather. Highs Wednesday and Thursday will be around 10-15 degrees
above normal, with low 90s possible in the lower deserts.
A cooling trend will start Friday and continue into next weekend
as onshore flow returns and the ridge weakens due to a trough
moving into the Pacific Northwest. This will also likely bring a
return of the marine layer.
&&
.AVIATION...
052030Z...Multiple SCT-BKN low cloud layers, with bases 3000-5000 ft
MSL and tops to 8000 ft MSL will continue today mainly over and west
of the mountains. Lower coastal slopes of the mountains will be
obscured through tonight. Isolated showers will continue moving into
Orange and SW San Bernardino Counties this afternoon, and move SE
over Riverside and San Diego Counties late this afternoon and this
evening. CIGS locally lowering to 1500 ft MSL with VIS 3-5 SM in
moderate showers. Stratus gradually clearing tonight into Monday
morning.
Southwest to west surface wind gusts of 40-60 kt will continue over
the ridges/desert slopes of the mountains and along the desert
slopes through. Areas of MOD-STG UDDFS/LLWS over/east of the
mountains are expected through the period, with rotors possible
near KPSP. Winds will gradually weaken late tonight.
&&
.MARINE...
Northwest wind gusts to 25 kt are likely at times over the outer
waters tonight through Monday night as an upper-level trough moves
across the region. A Small Craft Advisory for winds remains in
effect from this afternoon through Monday evening. Scattered showers
are possible today as the trough moves across the region. No
hazardous marine weather is expected Tuesday through Thursday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Wind Warning until 2 AM PST Monday for Apple and Lucerne
Valleys-Riverside County Mountains-San Bernardino County
Mountains-San Diego County Mountains-San Gorgonio Pass Near
Banning.
Wind Advisory until 2 AM PST Monday for Coachella Valley-San
Diego County Deserts.
PZ...Small Craft Advisory for winds from 4 PM this afternoon to 10 PM
PST Monday for Waters from San Mateo point to the Mexican
Border Extending 30 to 60 nm out including San Clemente
Island.
&&
PUBLIC...Harrison
AVIATION/MARINE...JJTThe national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
The Burns Canyon mesonet station reported multiple wind gusts of 78 mph over a 5 hour period.
The Whitewater RAWS station reported multiple gusts in excess of 70 mph over a 3 hour period.
The CWOP station in Borrego Springs reported a peak gust of 62 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2017Every state in 2017This day in weather historyWarnings in California, March 2017
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: 687544, 687545, 687546.