An upper trough moved through central California on December 9 pushing a frontal boundary through the area. This resulted in widespread precipitation across the area with much of the San Joaquin Valley receiving between a quarter inch to a half inch or rainfall.
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 trough moved through central California on December 9 pushing a frontal boundary through the area. This resulted in widespread precipitation across the area with much of the San Joaquin Valley receiving between a quarter inch to a half inch or rainfall. The Sierra Nevada which was more orographically favored received a half inch to an inch of liquid precipitation and several SNOTELs from Kings Canyon Park northward picked up an estimated 5 to 10 inches of new snowfall as the precipitation was mainly in the form of snow above 7000 feet. Precipitation amounts were generally less in the mountains and deserts of Kern County. Up to a quarter inch of rain fell across the Kern County Mountains and up to a tenth of an inch of rain fell across the Kern County Deserts. Gusty winds also accompanied this system across the Kern County Mountains and Deserts as several locations measured gusts between 35 and 55 mph and a few low impact indicator sites had gusts exceeding 60 mph. The trough moved east of the area during the evening of December 9 resulting in decreasing winds and the precipitation ending.
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 8, 3:34 PM PST, 9 hours 26 minutes earlier.
Area Forecast Discussion...UPDATED National Weather Service Hanford CA 334 PM PST Wed Dec 8 2021 .UPDATE... Updated AIR QUALITY ISSUES section. && .SYNOPSIS... A frontal system will impacts the region tonight and Thursday with rain and mountain snow. Sub-Freezing temperatures are likely in the Kern County deserts and much of the San Joaquin Valley Friday night and Saturday morning. A slow moving and robust storm system may impact our area early next week, bringing significant precipitation with it. && .DISCUSSION... A broad trough is pushing into and across the Western US over the next several days. On the backside of the broad trough is a shortwave moving into California, and impacting our area overnight and into tomorrow afternoon. There is an atmospheric river associated with that system, though the trajectory of the moisture transport is flowing more or less parallel with the San Joaquin Valley versus up the slopes of the Sierra. The main impact this will have is we will see less upslope precipitation, and more rain/snow across the eastern San Joaquin Valley and Sierra Foothills. Snow levels will begin around 8kft, but drop to around 5kft post frontal. FROPA is expected mid morning to midday. Heaviest rain/snowfall is expected with FROPA. However, precipitation is expected to be fairly light and persistent for most locations. Cold northwest flow aloft post frontal will dominate Friday before weak ridging develops on Saturday. This will result in some of the coldest temperatures we have seen this winter. Most ensembles and probabilities point to freezing temperatures across most of the San Joaquin Valley on Saturday morning, and a high probability of hard freezing conditions across the Mojave Desert. Then attention quickly turns to the next system early next week, which will have an atmospheric river with it, too, though the trajectory is more favors for upslope precipitation. Snow levels will begin lower and drop further than the first system, which means more snow is expected with the second. The second system will also be more prolonged event, and there is another system progged on its heels. Long story short, the ensembles point to consistent pattern in the extended portion of the forecast, which is very favorable for wetting rain/snow around the area, and persistent pattern change from the last several weeks. && .AVIATION... MVFR to IFR ceilings and visibility in the SJ Valley through 18z Wednesday in haze and mist. After 06Z Thursday, areas of MVFR and IFR with local LIFR and mountain obscuration in clouds and precipitation will spread southward across the region. Otherwise, VFR conditions will prevail across the central CA interior for the next 24 hours. && .AIR QUALITY ISSUES... On Thursday December 9 2021...Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno...Kern...Kern (Greater Frazier Park Area)...Madera and Tulare Counties. Further information is available at Valleyair.org && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is high. 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... Hard Freeze Watch from Friday evening through Saturday morning for CAZ337-339. Winter Weather Advisory from 7 PM this evening to 4 PM PST Thursday for CAZ323-326>331. Freeze Watch from Friday evening through Saturday morning for CAZ301>303-305-306-309>312-315-316. && public...Meadows aviation....Meadows weather.gov/hanford
The national radar mosaic for the moment the first event began.
4 winter weather, 4 high wind. Local standard time, as filed.
Several SNOTEL reports of 5 to 10 inches of estimated new snowfall.
Several SNOTEL reports of 5 to 10 inches of estimated new snowfall.
Several SNOTEL reports of 5 to 10 inches of estimated new snowfall.
Several SNOTEL reports of 5 to 10 inches of estimated new snowfall.
The Bird Springs Pass RAWS measured a peak wind gust of 72 mph.
The Bear Peak RAWS measured a peak wind gust of 59 mph.
The Walker Pass RAWS measured a peak wind gust of 61 mph.
The Indian Wells Canyon RAWS measured a peak wind gust of 64 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: 988356, 988357, 988358, 988359, 988311, 988313, 988312, 988314.