An area of low pressure slid down the west coast on November 6 which would eventually form a long wave trough over California. This would be the first series of winter storms for interior northern California during the wet season, which would lead to slick roads from rain and mountain snow.
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 STO wrote it up.
An area of low pressure slid down the west coast on November 6 which would eventually form a long wave trough over California. This would be the first series of winter storms for interior northern California during the wet season, which would lead to slick roads from rain and mountain snow. Snow reports for this system were a bit sparse as ski resorts in the Sierra were just starting to open back up for the winter season.
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 Sacramento, CA wrote its last area forecast discussion before the first event at Nov 7, 1:56 PM PST, 4 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 156 PM PST Sat Nov 7 2020 .SYNOPSIS... Scattered showers and moderate to locally heavy mountain snow expected tonight and Sunday. Breezy north to east winds possible Sunday into Monday with lowering humidity. Below average temperatures expected to continue through the week, with near freezing Valley temperatures expected Monday morning. && .DISCUSSION... Early this afternoon, radar indicates only some light returns over the Sierra Nevada with dry weather seen elsewhere. These drier conditions will only briefly hold before another round of mountain/foothill precipitation is expected to begin this evening as the main low continues to rotate across California and Nevada. Periods of moderate to locally heavy snow will begin to fall over the mountains beginning this evening, with the heaviest snowfall expected overnight into Sunday morning. Snow levels remain generally around 4.5 kft tonight but decrease into Sunday morning down to roughly 2.5-3.5kft. Hazardous mountain travel is expected during this time and a Winter Storm Warning remains in place for elevations above 4kft through tomorrow afternoon. Total snow accumulation during this time is generally from 5-8 inches, with locally higher amounts at higher mountain elevations. The weather system begins to push out of the area Sunday afternoon with some breezy north to east winds developing behind it. Gusts up to 30 mph are expected, with relative humidity values about 20 percent or higher. Cold air remains in place after this system exits and high pressure moves back across Northern California. Monday morning looks to see some of the coldest low temperatures of the week with Valley lows near freezing and mountain temperatures down into the single digits or teens. With some winds continuing into the overnight hours, conditions may stay mixed enough to stop a widespread freeze. Any localized areas that do reach freezing may see sensitive plants damaged. Dry weather remains in place through mid-week. && .EXTENDED DISCUSSION (Wednesday THROUGH Saturday)... Cluster ensemble analysis is in good agreement long wave troughing over the Western US will continue into mid-week and into the weekend before a more zonal pattern starts to emerge. This will likely bring rounds of cloudy and possibly unsettled weather to Northern California. The next best chance for unsettle weather is a low pressure system projected to dig south out of the Gulf of Alaska and impact Northern California by next weekend. This system is forecast to have some marine influence as well. Integrated water vapor transport analysis indicates moisture levels hitting the criteria for at least a weak atmospheric river associated with this disturbance. && .AVIATION... VFR conditions expected at the TAF sites the next 24 hours. Increasing clouds this evening becoming BKN around 050 overnight. Widespread IFR conditions expected over the northern Sierra by 06Z Sunday. Snow levels 040-050, lowering to 025-035 by 12Z Sunday. Surface wind gusts under 12 kts. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 4 PM PST Sunday for West Slope Northern Sierra Nevada. &&
2 winter storm, 1 winter weather. Local standard time, as filed.
A spotter reported 3 inches of snow accumulation at Pacific House.
Most ski resorts in the Sierra reported 6 to 10 inches of snow accumulation; however, Sierra at Tahoe, just south of highway 50, reported a storm 16 to 18 inches of new snow accumulation.
Caltrans reported 8 inches of new snow accumulation at Kingvale.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2020Every state in 2020This day in weather historyWarnings in California, November 2020
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: 931854, 931852, 931853.