A departing upper-level trough and subsequent upper ridge caused north and northeast winds aloft, combined with a relatively strong surface pressure gradient. This led to Santa Ana winds developing on the morning of April 7th.
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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 departing upper-level trough and subsequent upper ridge caused north and northeast winds aloft, combined with a relatively strong surface pressure gradient. This led to Santa Ana winds developing on the morning of April 7th.
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 Apr 6, 8:17 PM PST, 5 hours 43 minutes earlier.
Area Forecast Discussion
National Weather Service San Diego CA
917 PM PDT Wed Apr 6 2022
.SYNOPSIS...
Gusty Santa Ana winds will continue spreading dry and much warmer
air westward through Thursday. The heat will be most widespread
on Thursday and Friday, when the shallow marine layer will be
pushed out to sea. Until then, some dense coastal fog is possible
overnight. A strong ridge aloft will collapse over the weekend,
allowing more fog, and cooler air to spread inland. Much colder
air will arrive early next week, preceded by strong onshore winds
over the mountains and deserts, and the potential for widespread
rain and mountain snow on Tuesday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Update...
Patchy low clouds and fog continue along portions of the coast
this evening, mainly along the southern Orange County coast and
north of Oceanside in San Diego County as well as well as from
Point Loma south to the international border.
HRRR shows that this will continue through about 3 AM before the
Santa Ana winds strengthen and this offshore push acts to blow
the clouds and fog off the coast. Thus, widespread visibility
reduction impacts are not expected overnight. Made modifications
to the sky grids. Otherwise, no changes to the forecast were made
this evening.
The heat is the big weather story. Temperatures on Thursday and
Friday will soar into the 90s inland with even a few triple digits
expected. Thursday will be the hottest day towards the coast as
this is when the Santa Ana winds will be strongest. Inland, both
days will be hot. H85 temps actually peak on Friday, but onshore
winds make a return then. Some inland locales could see the peak
of the heat occur on Friday before the sea breeze moves inland.
Friday and Saturday will be hottest over the deserts.
Previous Discussion....
Satellite imagery this afternoon showed fog over the inner coastal
waters and locally onto the beaches. The offshore sfc pressure
gradient (KTPH-KSAN) was holding around 10 MBS. Gusty easterly winds
at 25 MPH with gusts around 40 MPH were occurring along the offshore
wind-prone coastal slopes and below passes at 1 PM PDT. Wind
Advisories are in effect for these areas through Thursday afternoon.
Onshore flow prevails along the coast and will keep coastal areas
cool today. It could also bring some of that coastal fog farther
inland over the coastal strip tonight. As the gradient trends back
offshore later tonight, most of that should drift back out to sea.
In the meantime, areas of dense fog are possible for coastal areas
through tonight.
High pressure centered SW of San Diego today, will drift east
through Friday. The ridge peaks along the coast at 586 DM on
Thursday, then rapidly deflates as a trough moves inland over the
PacNW. Hottest weather will be Thu/Fri when much of the coastal
basin could see daytime highs that are 20+F above average. Mts/
deserts closer to 15+F. Even the coast should get quite warm as
the air over the Bight is modified. Heat Advisories are in effect
through Fri when moderate heat risk is forecast. Noticeable cooling
will occur on Saturday as the PacNW trough ramps up the onshore
flow. Wind Advisories may be needed for the mts/deserts. This will
bring additional cooling through Sunday.
For early next week, a broad trough is forecast to develop over the
West. Several shortwaves will follow the initial PacNW shortwave,
deepening the trough. The most significant one will dive south along
the CA Coast on Monday. Once again, onshore flow will strengthen and
could get quite strong over the mts/deserts, building the marine
layer inland to the coastal slopes. Timing this wave is fairly close
on the GFS/ECMWF 12Z runs, arriving on Tuesday, but trailing energy
is considerably different. The GFS control digs more energy with
another shot of very cold air south through Wednesday, while the
ECMWF control moves it rapidly east on Wednesday. The GFS control is
on the more aggressive end of the mean.
Based on a consensus of ensemble members, a 06Z-18Z Tue arrival of
QPF looks more certain than amounts, or how long it will linger. So
count on some precipitation about Tuesday, and much colder weather.
By Tuesday, daytime highs will be around 10F below average. That
will be a 30+F swing from Thu/Fri.
&&
.AVIATION...
070230Z...Low clouds and fog likely to redevelop this evening and
linger overnight. Cloud bases will be 500-800 ft MSL with VIS 1-3
miles at times. Moderate confidence in impacts at coastal TAF sites
06Z-12Z Thursday.
Areas of northeast winds 20-30 kt with gusts up to 45 kt will
continue through Thursday morning. Strongest winds expected on the
coastal mountain slopes and foothills as well as below mountain
passes. Pockets of LLWS and strong up/downdrafts likely over and
west of mountains. Winds then steadily diminish through Thursday
afternoon.
&&
.MARINE...
Patchy fog with visibility 1 mile or less at times through tonight.
Otherwise, no hazardous marine weather is expected through Sunday.
&&
.BEACHES...
Surf is expected to gradually decrease through the evening and
overnight hours. Elevated surf may then return later this weekend as
more longer-period westerly swell makes its way toward the coast
Saturday and Sunday.
&&
.FIRE WEATHER...
High pressure aloft and offshore flow will bring hot and dry weather
through Friday. Minimum RH values of 5-10%, heat, and gusty Santa
Ana winds will elevate fire weather conditions, mainly along the
coastal slopes and foothill areas. The most widespread easterly
winds of 20-35 MPH with gusts around 50 MPH will be on Thursday
morning. Weak onshore flow will prevail west of the foothills today,
and return later on Friday along the coast.
Strengthening onshore flow will spread cooling and higher coastal
humidity inland on Saturday, with continued cooling and humidity
recovery for Sunday into early next week. Wetting rain is possible
by Tuesday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 4 PM PDT Thursday for Orange County Inland
Areas-San Bernardino and Riverside County Valleys-The
Inland Empire-San Diego County Valleys-Santa Ana Mountains
and Foothills.
Heat Advisory until 6 PM PDT Friday for Orange County Coastal
Areas-Orange County Inland Areas-San Bernardino and
Riverside County Valleys-The Inland Empire-San Diego County
Coastal Areas-San Diego County Valleys.
PZ...NONE.
&&
PUBLIC...Gregoria (Update)/10 (Previous Discussion)
AVIATION/MARINE...AdamsThe national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
Santa Ana winds impacted the San Diego County Mountains on the morning of April 7th. Wind gusts of 45-55 mph were common across the area. The Sill Hill SDGE site recorded a peak wind gust of 70 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, April 2022
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: 1019547.