High Wind in California, April 5, 2021

Name: High Wind in California, April 5, 2021
Start: 2021-04-05T11:27
End: 2021-04-05T15:32
Location: California

April 5, 2021 · NWS HNX · 7 events in 3 counties and zones

The toll

Deaths: 0
Injuries: 1
Property damage: $12,000
Crop damage: None recorded
Events: 7

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.

What happened

The episode as NWS HNX wrote it up.

An upper low pressure system which dropped southward through the Great Basin on April 5 interacted with a strengthening ridge off the California coast producing a strong pressure gradient over the Kern County Mountains and Deserts. This resulted in a period of strong wind gusts between the early morning of April 5 and the early morning of April 6 when the winds diminished after the ridge built inland resuting in lowering pressure gradients. The strongest gusts occurred during the afternoon of April 5 when several stations measured gusts exceeding 40 mph. Several low impact indicator sites reported gusts exceeding 55 mph.

What forecasters said that day

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 Hanford, CA wrote its last area forecast discussion before the first event at Apr 5, 2:02 AM PST, 9 hours 25 minutes earlier.

Area forecast discussion, Apr 5, 2:02 AM PST, 9 hours 25 minutes before

Area Forecast Discussion
National Weather Service Hanford CA
302 AM PDT Mon Apr 5 2021

.SYNOPSIS...
An area of low pressure will move across the Great Basin today
bringing strong and gusty winds to the East Sierra and Kern County
mountains and desert. In the wake of the low pressure system a
ridge of high pressure will become established over the West Coast
keeping the weather pattern dry for the next week.

&&

.DISCUSSION...
Cool onshore surface flow helped keep temperatures down across the
San Joaquin Valley on Easter Sunday, where highs were generally in
the lower to mid 70s, just slightly above climatological normals for
early April. But outside of the valley, temperatures were well above
normal with much of the mountains and desert around 15 degrees above
climo. The increased onshore surface flow was due to an upper trough
moving over the Pacific Northwest, causing the pressure gradient to
tighten across the coast. Strong westerly winds developed across a
portion of the Kern County mountains and desert Sunday afternoon as
well, where a Wind Advisory was and still is in effect.

The upper trough will dive southeast over the northern Great Basin
today. This will cause another increase in winds this afternoon,
with strong west to northwest gusts expected across a portion of the
Kern County mountains and desert. The Wind Advisory for this area is
in effect through 5 AM Tuesday. Breezy conditions will occur across
the SJ Valley today with local gusts 20 to 25 mph. Temperatures will
again be at to slightly above normal in the SJ Valley today. Cooling
will occur across the mountains and desert today with highs generally
5 to 10 degrees above climo.

The trough shifts east over the Rockies on Tuesday as a ridge of high
pressure amplifies over the West Coast through Wednesday. On Thursday,
the ridge axis shifts offshore as an upper trough drops down over the
Pacific Northwest. This feature is expected to stay a little farther
north than the current one and thus no chance for precipitation. The
main impact will be another round of gusty winds Thursday into Friday.
This pattern looks to continue into next weekend as models show yet
another trough following a similar path through the Pacific Northwest.

&&

.AVIATION...VFR conditions will prevail across the Central California
interior for at least the next 24 hours.

&&

.AIR QUALITY ISSUES...
None.

&&

.CERTAINTY...

The level of certainty for days 1 and 2 is high.
The level of certainty for days 3 through 7 is medium.

Certainty levels include low...medium...and high. Please visit
www.weather.gov/hnx/certainty.html for additional information
an/or to provide feedback.

&&

.HNX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 5 AM PDT Tuesday for CAZ196>199.

&&

Public/Aviation/Fire Wx...DCH
PIO/IDSS..................BS

weather.gov/hanford

Event by event

7 high wind. Local standard time, as filed.

High Wind, Tehachapi Area

When: April 5, 11:27 AM PST
Where: Tehachapi Area forecast zone
Measured: 63 kt (72 mph) measured gust
Reported by: RAWS

The Bird Springs Pass RAWS measured a peak wind gust of 72 mph.

High Wind, Lake Isabella

When: April 5, 12:10 PM PST
Where: Lake Isabella forecast zone
Measured: 50 kt (58 mph) measured gust
Reported by: RAWS

The Bear Peak RAWS measured a peak wind gust of 58 mph.

High Wind, Indian Wells Valley

When: April 5, 1:44 PM PST
Where: Indian Wells Valley forecast zone
Measured: 52 kt (60 mph) estimated gust
Injuries: 0 direct, 1 indirect
Property damage: $12,000
Reported by: Law Enforcement

California Highway Patrol reported a semi-trailer blown over at the intersection of SR 14 and Indian Wells Canyon Road. One minor injury was reported.

High Wind, Lake Isabella

When: April 5, 2:10 PM PST
Where: Lake Isabella forecast zone
Measured: 55 kt (63 mph) measured gust
Reported by: Utility Company

The Southern California Edison station at Grapevine Canyon Road measured a peak wind gust of 63 mph.

High Wind, Tehachapi Area

When: April 5, 3:14 PM PST
Where: Tehachapi Area forecast zone
Measured: 51 kt (59 mph) measured gust
Reported by: RAWS

The Jawbone Canyon RAWS measured a peak wind gust of 59 mph.

High Wind, Indian Wells Valley

When: April 5, 3:26 PM PST
Where: Indian Wells Valley forecast zone
Measured: 84 kt (97 mph) measured gust
Reported by: RAWS

The Indian Wells Canyon RAWS measured a peak wind gust of 97 mph.

High Wind, Lake Isabella

When: April 5, 3:32 PM PST
Where: Lake Isabella forecast zone
Measured: 60 kt (69 mph) measured gust
Reported by: RAWS

The Blue Max RAWS measured a peak wind gust of 69 mph.

What these are

High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2021 Every state in 2021 This day in weather history Warnings in California, April 2021

Sources

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: 941786, 941789, 941794, 941792, 941788, 941785, 941787.