An upper level shortwave system which dropped southeast through the Great Basin on December 31 produced increased surface pressure gradients which resulted in strong downslope winds along the Mojave Desert slopes of the Tehachapi Mountains during the afternoon and evening hours. Several stations measured wind gusts exceeding 45 mph with a few stations reporting gusts exceeding 60 mph.
Every event with a place to put it; 8 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 HNX wrote it up.
An upper level shortwave system which dropped southeast through the Great Basin on December 31 produced increased surface pressure gradients which resulted in strong downslope winds along the Mojave Desert slopes of the Tehachapi Mountains during the afternoon and evening hours. Several stations measured wind gusts exceeding 45 mph with a few stations reporting gusts exceeding 60 mph.
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 Dec 31, 1:51 PM PST, 1 hour 19 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 151 PM PST Fri Dec 31 2021 .SYNOPSIS... Cold and dry weather will prevail this weekend with areas of night and morning dense fog in the San Joaquin Valley. Trending a little warmer next week with a chance of precipitation from Fresno County northward on Friday. && .DISCUSSION... Low clouds and fog have persisted in portions of the Kern County mountains today. Area webcams and observations show dense fog is still occurring along Interstate 5 through the Grapevine towards southern California. Dense fog is also affecting Hwy 58 from the San Joaquin Valley to Tehachapi. A Dense Fog Advisory remains in effect until 3 PM this afternoon. There were some patches of fog across the SJ Valley this morning as well, mainly around Fresno. Satellite loops show an extensive area of stratus clouds remains over much of the SJ Valley and adjacent foothills. Some clearing is occurring from Merced County south to Kings County as a short wave trough dives down from the north. This trough will parallel the CA/NV border tonight and should keep a light breeze going in the valley to inhibit fog development. But the winds might abate enough towards morning for some dense fog to develop. Low clouds are likely to persist across the southern end and along portions of the eastern side of the valley. A northerly flow will usher in a colder air mass on Saturday. High temperatures across the SJ Valley Saturday afternoon are forecast to remain in the middle to upper 40s, around 7 to 10 degrees below normal. This will be followed by widespread freezing temperatures Saturday night, with some rural areas falling to around 28 degrees. A warming trend will follow with temperatures back to near normal early next week. Ensembles are now keeping precipitation north of our area through the middle of next week. The next chance develops Friday of next week with low chance POPs from Fresno County north. && .AVIATION... MVFR with areas of IFR conditions due to upslope clouds and fog in the valley facing slopes in Kern County. Areas of IFR in fog developing across the San Joaquin Valley from 08z-18z Saturday. && .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... Dense Fog Advisory until 3 PM PST this afternoon for CAZ334-335. && Public/Aviation/Fire Weather...DCH PIO/DSS........................CMC weather.gov/hanford
The national radar mosaic for the moment the first event began.
8 high wind. Local standard time, as filed.
The Cache Creek CHP station measured a peak wind gust of 64 mph.
The Bird Springs Pass RAWS measured a peak wind gust of 65 mph.
The Southern California Edison station at Little Oak Canyon measured a peak wind gust of 63 mph.
Jawbone Station measured a peak wind gust of 58 mph.
The Southern California Edison station at Cottonwood Canyon measured a peak wind gust of 58 mph.
The Jawbone Canyon RAWS measured a peak wind gust of 71 mph.
The Southern California Edison station at 20W Rosamond measured a peak wind gust of 59 mph.
The Southern California Edison station at Cache Creek measured a peak wind gust of 66 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, December 2021
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: 990859, 990857, 990860, 990863, 990862, 990856, 990861, 990858.