Another cold upper low pressure system pushed through central California between the morning of December 27 and the morning of December 28. 5 inches of liquid precipitation with several higher elevation SNOTELs picking up 8 to 16 inches of new snowfall.
Every event with a place to put it; 10 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.
Another cold upper low pressure system pushed through central California between the morning of December 27 and the morning of December 28. Several stations in the Sierra Nevada adjacent foothills picked up between 0.75 inches and 1.5 inches of liquid precipitation with several higher elevation SNOTELs picking up 8 to 16 inches of new snowfall. Several stations in the Sierra foothills and Tehachapi Mountains picked up between 1 and 3 inches of new snowfall. Most of the San Joaquin Valley picked up between a quarter inch and a half inch of rain. This system also produced a period of strong wind gusts in the Kern County Mountains and Deserts during the afternoon and evening of December 27 as the main cold front pushed through the area. Several stations reported gusts exceeding 40 mph with a few low impact indicator sites briefly measuring gusts exceeding 65 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 27, 2:40 AM PST, 1 hour 20 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 240 AM PST Mon Dec 27 2021 .SYNOPSIS... A cold storm system will move into the region this morning and continue through the day into this evening with snow levels dropping into the Sierra foothills and Kern county pass level. Clearing on Tuesday as the storm moves out with yet another storm expected on Wednesday. The unsettled weather continues through Friday with clear and cold conditions this coming weekend. && .DISCUSSION... A series of strong storms continue to produce unsettled weather conditions across Central California. The latest storm, based on satellite and upper air analysis, is currently near the Washington/ Oregon Coast this morning and slowing shifting southward. Regional Doppler radar is showing light to moderate precipitation over Northern California and reaching Merced/Yosemite NP. As the latest storm reaches Central California surface pressure gradients have relaxed as KSFO to KLAS is now down to 3.5mb. Therefore, winds will not be an issue for the lower elevations while upper air observations show stronger winds aloft in the area of the Winter Storm. Upper air observations are also showing the freezing line at around 4000 feet MSL this morning. While snow will still drop today and fall below the 4000 foot line (closer to 2500-3000 feet) before more cold air lowers the snow line on Tuesday. The forecast is calling for a one two punch of storms to affect Central California before a cut off low forms toward the end of the week. Ensemble models have a very good handle on the current storm as it drops from the Pacific Northwest. While a bit slower then previous ensemble runs, the storms intensity has changed little during the last few days. Ensemble moisture analysis is indicating significant amounts being drawn in (while not an atmospheric river) to produce over 2 feet of new snow over the higher elevations of the Sierra Nevada in the 24 hours. Even the lower end of the probabilistic spectrum (what is more likely to occur) is showing Winter Storm Warning criteria snow amounts. Therefore, confidence is high that a major storm will hit the higher elevations along with significant snow reaching the Sierra Foothills near the 2000 foot elevation line. This elevation line will also affect the Kern County Mountains as snow will fall at the pass levels of both Highway 58 and Interstate 5. Ensembles are in fairly good agreement with pushing a majority of the current storms energy out by Tuesday morning (ahead of the next storm on Wednesday). Yet, behind the storm, cold air will filter in the region that will have not time to modify before the arrival of the next storm. Therefore, Wednesday’s storm will have snow reaching the lower foothills. While the second storm will not have the energy of the first storm (and not have the precipitation amounts), it has the potential of producing snow near the San Joaquin Valley floor. Ensemble vertical profile analysis has many of its members just under a 1000 feet with outliers down to 700 feet. It will be close if snow is able to reach the valley floor. Thursday will see lingering showers before the storm exits closer to the Friday time frame. At that time, models begin forming a low off the Southern California Coast as certainty before to fall on the outcome of what will happen to the low. Ensembles attempt to move the low toward Baja California and away from the region. At this point, will keep the weekend dry as an inside slider shows little promise of precipitation. && .AVIATION... MVFR conditions are likely across the San Joaquin Valley and lower Sierra Foothills in and near showers over the next 24 hours. Mountain obscurations with areas of IFR conditions are expected in the Sierra Nevada through 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... Winter Weather Advisory until 10 PM PST this evening for CAZ332>336. Winter Storm Warning until 10 PM PST this evening for CAZ318-320- 322>331. && Public/Aviation/Fire Wx...Molina PIO/IDSS/Social Media.....CMC weather.gov/hanford
The national radar mosaic for the moment the first event began.
6 winter weather, 4 high wind. Local standard time, as filed.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
Several SNOTEL reports of 8 to 16 inches of estimated new snowfall.
The Bear Peak RAWS measured a peak wind gust of 80 mph.
The Jawbone Canyon RAWS measured a peak wind gust of 68 mph.
The Walker Pass RAWS measured a peak wind gust of 65 mph.
The Bird Springs Pass RAWS measured a peak wind gust of 85 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: 990445, 990446, 990447, 990448, 990449, 990450, 990443, 990441, 990444, 990442.