Gusty northwest winds impacted sections of Southwestern California. Peak wind gusts, up to 73 MPH, were reported across some mountain, valley and island locations.
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 LOX wrote it up.
Gusty northwest winds impacted sections of Southwestern California. Peak wind gusts, up to 73 MPH, were reported across some mountain, valley and island locations.
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 Los Angeles, CA wrote its last area forecast discussion before the first event at Apr 3, 10:02 AM PST, 3 hours 11 minutes earlier.
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
1102 AM PDT Mon Apr 3 2023
.SYNOPSIS...03/927 AM.
A inside slider trough will support much cooler temperatures
arriving on gusty northerly winds, with damaging winds possible
in the mountains and deserts through tonight. Continued offshore
flow and a ridge building in from the west will support a warmup
with widespread highs in the 70s and 80s possible by the weekend.
&&
.SHORT TERM (TDY-WED)...03/927 AM.
***UPDATE***
Forecast largely on track this morning. Gusty northwest winds are
nearing warning levels across the mountains and Antelope Valley
with mountain wave undulating clouds noted on satellite imagery.
Guidance supports further strengthening, especially late morning
into the afternoon. Strong cold air advection with the winds will
wash out the marine layer that was barely hanging on across the LA
Basin this morning, and lead to widespread advisory level winds
outside of the current slate of High Wind Warnings. Current wind
products look well placed with no adjustments at this time. The
inclusion of the normally wind sheltered San Gabriel Valley in
particular seems well placed as a developing inversion around
10000 feet above the surface may support local mountain wave
induced damaging wind (20-30 percent chance) late this afternoon
or early evening, especially across the foothills.
Low clouds banked up against the mountains near the Kern County
border, mainly on the Kern County side, produced a light coating
of snow with snow levels down to around 3000 feet. Light
accumulations have been observed on the I-5 near the Grapevine
with police escorts in place at one point to ensure safe travel
over the Grapevine. The moisture is dwindling, so snow showers
should gradually end later this morning. Low level moisture
returns tonight, but model guidance doesn't produce much if even
snow. Will follow the latest guidance to see if a slight chance of
snow needs to be added to the forecast.
***From Previous Discussion***
All systems go for a major wind event today and today (and esp
this evening). A cold (532 dam) inside slider will move down the
CA/NV border over the next 18 hours. It will bring very strong
northerly upper level flow to the area along with a great deal of
cold air advection which will help drive the strong winds downward
towards the sfc.
Currently an eddy and strong onshore flow to the east as well as
northerly flow across the San Joaquin Vly have brought low clouds
to all most the entire forecast area save for the SBA south coast
where north winds have kept them form moving in. These low clouds
will persist until the north winds develop and mix them out which
should occur sometime this morning. The eddy may deepen the marine
layer enough that when combined with some orographic lift from the
coastal slopes it will produce some rain. Still only a 20 percent
chc of any rain developing. A better chc of precip across the
north slopes of the mtns along the Kern county line as northwest
flow combine with low-level moisture in the San Joaquin Valley
to produce clouds and a chance of light precipitation. The cold
air advection will lower snow levels to around 2500 feet this
morning. A dusting to 2 inches of snow are possible today. The
Tejon Pass on I-5 will see a dusting to 1 inch of snow.
The widespread gusty northwest to north winds will really kick
into gear this afternoon and will peak this evening. Warning level
gusts 60 to 70 mph are very likely across the interior mountains,
Antelope Valley, and Santa Clarita Valley. The rest of the
forecast area will not reach the 58 mph warning threshold but will
see advisory level gusts between 35 to 55 mph. There is also a
high probability of mountain wave activity on this afternoon and
evening with the greatest likelihood over the LA county mountains
and Antelope Valley due to the orientation and strength of the
upper level winds. If a mountain wave touches down over the one of
the valleys it could cause substantial damage and this threat
will have to be monitored closed during the peak hours. These
strong winds will bring the possibilty of downed trees/tree
limbs and power outages. Additionally, the winds across the Antelope
Valley will likely produce clouds of blowing dust which could
bring visibilities to near zero at times.
High temperatures on today will plummet down into the 50s and
lower 60s across coastal and valley areas. The cold temperatures
and strong winds will cause wind chill readings to fall to around
0 degrees in the mountains.
There will be some lingering wind on Tuesday, but much weaker
than Monday and likely limited to the interior regions. Areas
currently covered by wind warnings may need low end wind
advisories for gusts to 45 mph through some part of the day.
Tuesday's wake up temperatures will be well below normal due to
the cold dry airmass and clear skies. Widespread lows in the 30s
with frost are possible in the wind sheltered portions of the
vlys. Max temps will warm under sunny skies but will remain well
below normals and mostly in the lower lower 60s.
More warming is expected on Wednesday as hgts rise in the wake of
the departing trough and a little Santa Ana develops. The
offshore flow and the sunny skies will boost max temps into the
mid to upper 60s.
.LONG TERM (THU-SUN)...03/305 AM.
Medium range deterministic and ensemble based (GEFS, EPS) agree
that long over-do first warm up of 2023 will occur from Thursday
through the weekend.
Upper level flow will be from the NW at first and then turn to the
west. Hgts on Thu will rise to 568 dam and by the weekend they
will rise further to near 578 dam. There will only be weak onshore
flow to the east and weak offshore flow from the north. There does
not look like there will be any eddies and its likely there will
be no marine layer clouds. Look for 6 to 8 degrees of warming on
Thursday followed by 2 to 4 additional degrees of warming each
day Fri - Sat. The weekend will see vly temps move into the lower
80s and all areas will have max temps 3 to 5 degrees above normal.
&&
.AVIATION...03/1802Z.
At 1702Z at KLAX, a moist layer was 6600 feet deep. The top of
the inversion was 9000 feet with a temperature of -3 C.
Moderate confidence in all TAFs. All TAF sites will be clear in a
few hours. High confidence that winds will be much stronger than
normal but lower confidence on exact timing of wind changes. UDDFS
and LLWS could be widespread this afternoon into this evening,
especially in the vicinity of mountains and mountain passes.
KLAX...Moderate confidence in TAF. High confidence that there
will not be an east wind component and high confidence that the W
winds will be stronger than normal and will shift to N 09-15Z
Tuesday with cross winds out of the north gusting to 25 knots or
more.
KBUR...Moderate confidence in TAF. Increasing northwesterly flow
could generate some LLWS/turbulence through 08z.
&&
.MARINE...03/942 AM.
Overall, moderate to high confidence in current forecast. Strong
northwest winds will impact all the coastal waters through tonight.
Gale force winds are likely for all areas today. So, current
slate of GALE WARNINGS looks good through tonight.
For Tuesday through Wednesday, high confidence in SCA level winds
continuing across all waters with gusts 25 to 30 kt. There is also
a 30 percent chance of GALE force winds across portions of the
outer waters Tuesday afternoon and evening.
For Thursday and Friday, the winds will continue to slowly
diminish. High confidence in SCA level winds continuing across the
Outer Waters. For all the Inner Waters, winds and seas will
generally remain below SCA levels, although there is a 50% chance
of SCA level winds across the western half of the Santa Barbara
Channel on Thursday.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory in effect until 11 PM PDT this evening for
zones 38-340>344-346>348. (See LAXNPWLOX).
Freeze Warning in effect from 3 AM to 8 AM PDT Tuesday for
zones 38-343-344-381>383. (See LAXNPWLOX).
High Surf Advisory in effect until 11 AM PDT Tuesday for
zones 87-340-346-354-362-366. (See LAXCFWLOX).
Wind Advisory in effect until 5 AM PDT Tuesday for zones
87-349-350-352-354>358-362-366>375-548. (See LAXNPWLOX).
Wind Advisory in effect until 6 PM PDT this evening for zone
88. (See LAXNPWLOX).
High Wind Warning in effect from 6 PM this evening to 5 AM
PDT Tuesday for zone 88. (See LAXNPWLOX).
Frost Advisory in effect from 3 AM to 8 AM PDT Tuesday for
zones 341-347-348-356>358-371. (See LAXNPWLOX).
High Wind Warning in effect until 5 AM PDT Tuesday for zones
345-351-353-376>383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 1 PM PDT this afternoon
for zone 645. (See LAXMWWLOX).
Gale Warning in effect until 11 PM PDT this evening for zones
645-650-655. (See LAXMWWLOX).
Gale Warning in effect until 3 AM PDT Tuesday for zones
670-673-676. (See LAXMWWLOX).
&&
PUBLIC...Rorke
AVIATION...Sweet/Schoenfeld
MARINE...Sweet/Schoenfeld
SYNOPSIS...Munroe
weather.gov/losangeles
Experimental Graphical Hazardous Weather Outlook at:
https://www.weather.gov/erh/ghwo?wfo=loxThe national radar mosaic for the moment the first event began.
6 high wind. Local standard time, as filed.
Strong northwest winds impacted Santa Barbara Island. A sensor on the island reported wind gusts up to 67 MPH.
Strong northwest winds impacted Santa Rosa Island. A sensor on the island reported wind gusts up to 69 MPH.
Strong northwest winds impacted the western section of the San Gabriel Valley. The sensor at Whiteman Airport, in Pacoima, reported wind gusts up to 69 MPH.
Strong northwest winds impacted the Santa Clarita Valley in Los Angeles county. The RAWS sensor at Saugus reported wind gusts up to 69 MPH.
Strong northwest winds impacted the western range of the San Gabriel Mountains. The RAWS sensor at Camp Nine reported wind gusts up to 59 MPH.
Strong northwest winds impacted the southern mountains of Ventura county. The sensor at Sycamore Canyon reported wind gusts up to 73 MPH.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, April 2023
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: 1099525, 1099526, 1099519, 1099520, 1099521, 1099522.