Skies cleared out and winds diminished behind a departed trough during the morning of December 10. A cold northwest flow provided for enough mixing; however, to limit the extent of fog coverage in the San Joaquin Valley and dense fog was localized for just a few hours during the morning.
Every event with a place to put it; 2 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.
Skies cleared out and winds diminished behind a departed trough during the morning of December 10. A cold northwest flow provided for enough mixing; however, to limit the extent of fog coverage in the San Joaquin Valley and dense fog was localized for just a few hours during the morning.
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 10, 4:32 AM PST, 8 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 432 AM PST Fri Dec 10 2021 .SYNOPSIS...Dry and cool conditions will prevail through Saturday. Freezing temperatures are expected across much of the San Joaquin Valley tonight with sub freezing conditions in the Kern Desert. A slow moving storm system may bring significant precipitation from late Sunday night through Tuesday. && .DISCUSSION... Quiet weather across the central California interior early this morning. Yesterday's system brought some much need precipitation to the region with several gauges in the Sierra Nevada reporting around 1 inch of rainfall. Rain amounts in the San Joaquin Valley generally ranged from a tenth to a quarter of an inch with a few outliers from a third to one half of an inch. Pressure gradients ramped up for gusty winds through the Kern County mountain passes last evening but are now weakening. Satellite loops show a batch of high clouds moving over within the northwest flow aloft. Some low clouds are also visible beneath the shield of cirrus. These clouds should clear out later this morning with mostly sunny but cool conditions by afternoon. High temperatures will be in the lower 50s across the San Joaquin Valley this afternoon, which is around 4 to 8 degrees below climatological normals. Clear skies and light winds Friday night will allow for optimum radiational cooling to occur. The latest NBM probabilistic guidance is giving much of the San Joaquin Valley a 50-60% chance of temperatures falling to 32 degrees or lower. A Freeze Warning has been issued for a portion of the SJ Valley tonight through Saturday morning. Some rural areas could bottom out as low as 28 degrees. Fresno and Bakersfield are expected to stay in the mid 30s due to the heat island effect. NBM guidance only gives them a 1% chance of falling to 32 degrees. Even colder conditions will occur in the Kern County Desert tonight. NBM guidance shows temperatures are likely to fall below 28 degrees across much of the Desert tonight with a few locations as low as 21 degrees. The airmass will modify a little over the weekend with temperatures climbing back to near normal. Medium range models continue to show a strong storm system dropping down from the Gulf of Alaska this weekend and spreading significant precipitation over California through early next week. Precipitation is forecast to arrive across Merced and Mariposa Counties on Sunday afternoon. But the front stalls for around 12-24 hours with little southward progress. The brunt of the event for central California is focused on Monday evening through Tuesday when periods of moderate to heavy rain and mountain snow are likely. Latest QPF for the San Joaquin Valley ranges from 1.5" across Fresno County northward to 0.75" across the southern end of the valley in Kern County. 2 to 6 inches liquid is forecast across the Southern Sierra Nevada. Snow levels will generally be above 5000 feet for most of the event. A Winter Storm Watch has been issued for the Sierra Nevada from late Sunday night through late Tuesday night. Total snow accumulations of 1 to 4 feet above 5000 feet with localized accumulations up to 6 feet possible over higher elevations. The Kern County mountains are looking at 1 to 3 inches QPF. Snow levels should remain above the major passes in Kern County for most of the event. The Desert could get up to one half of an inch of rain. The system exits to the east on Wednesday but another weaker system may follow quickly on it's heels for a little more wet weather on Thursday. && .AVIATION...In the San Joaquin Valley, areas of MVFR and local IFR visibilities in mist/haze until 18z Friday. Elsewhere, VFR conditions will prevail across the central CA interior for the next 24 hours. && .AIR QUALITY ISSUES... On Friday December 10 2021...Fireplace/Wood Stove Burning Status is: No Burning Unless Registered in Fresno...Kern...Kings...Madera...Merced 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 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... Hard Freeze Warning from 11 PM this evening to 9 AM PST Saturday for CAZ337-339. Hard Freeze Watch from Saturday evening through Sunday morning for CAZ337-339. Winter Storm Watch from late Sunday night through late Tuesday night for CAZ323-326>331. Freeze Warning from 11 PM this evening to 9 AM PST Saturday for CAZ301>303-305-306-309>312-315-316. && Public/Aviation/Fire Wx...DCH PIO/IDSS..................DS weather.gov/hanford
The national radar mosaic for the moment the first event began.
2 dense fog. Local standard time, as filed.
Visibility below a quarter mile was reported in Fresno.
Visibility below a quarter mile was reported in Visalia.
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: 988360, 988361.