The dense fog which prevailed over much of the San Joaquin Valley on January 7 lifted into a stratus deck which expanded toward the valley facing slopes of the Sierra foothills and Kern County Mountains. Northerly flow resulted in the stratus banking up in the Fort Tejon and Tehachapi areas which resulted in dense fog which impacted travel over the Tejon and Tehachapi passes on January 8.
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.
The dense fog which prevailed over much of the San Joaquin Valley on January 7 lifted into a stratus deck which expanded toward the valley facing slopes of the Sierra foothills and Kern County Mountains. Northerly flow resulted in the stratus banking up in the Fort Tejon and Tehachapi areas which resulted in dense fog which impacted travel over the Tejon and Tehachapi passes on January 8. Downslope wind gusts impacted the ridge tops and below the passes in Kern County Mountains during the morning hours of January 8 with several locations measuring gusts exceeding 45 mph, and a few low impact indicator sites briefly measuring gusts exceeding 55 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 Jan 7, 5:25 PM PST, 2 hours 35 minutes earlier.
Area Forecast Discussion...Updated National Weather Service Hanford CA 525 PM PST Tue Jan 7 2020 Updated Air Quality Issues section .SYNOPSIS... A couple of weak weather disturbances will move through the Central California Interior this week. The first will skirt the north mainly during Wednesday morning with a second system arriving Thursday. Unsettled weather will return on Saturday, though light precipitation is expected with each system. && .DISCUSSION... Dense fog has lifted into a stratus deck across the San Joaquin Valley today with temperature remaining in the upper 40s to around 50 all day today. Regional satellite loop indicates a steady stream of high clouds moving across the stratus deck. A weather system is forecast to move across the CENCAL interior overnight tonight. The forecast system is expected to remain dry as it moves across the rejoin. However some upslope clouds and light precip is forecast to develop over the north facing slopes of the Kern county mountains. Winds will also increase on the downslope side of the kern county mountains that will impact the Mojave area overnight and into tomorrow morning. NW flow will prevail over the region on Wednesday and Wednesday night as another stronger cold front will move across the area on Thursday. This system will have some moisture with it and will provide a chance of showers across CENCAL on Thursday. Cooler temperatures are expected through the rest of the week. Another cold front will push through the region on Saturday night. This system will be moisture starved, but is expected to once again produce gusty winds below the Kern county mountain passes on Saturday night into Sunday. Models are very different beyond Saturday and the deterministic run of the GFS is bringing another system in her by Tuesday morning. Confidence is very low with the forecast due to run to run inconsistency. && .AVIATION... In the San Joaquin Valley, Kern county mountains and adjacent Sierra foothills... Mist and low ceilings will create widespread MVFR conditions through 21z Wednesday. Areas of IFR/VLIFR are possible after 12z Wednesday in the SJV due to patchy fog and in the Kern County mountains due to low clouds and precipitaton. VFR conditions will otherwise prevail over the central California interior during the next 24 hours. && .AIR QUALITY ISSUES... On Wednesday, January 8th, 2020, fireplace/wood stove burning status is: no burning unless registered in Fresno, Kern, and Madera Counties. Furter information can be found at Valleyair.org. && .CERTAINTY... The level of certainty for days 1 and 2 is low. The level of certainty for days 3 through 7 is low. Certainty levels include low, medium, and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 1 AM to 10 AM PST Wednesday for CAZ198-199. && public...JDB aviation....DS weather.gov/hanford
3 dense fog, 1 high wind. Local standard time, as filed.
California Highway patrol reported very low visibility on I-5 north of the Tejon Pass and paced traffic at times. Webcams showed very low visibility in the Grapevine and El Tejon areas.
The Blue Max RAWS measured a peak wind gust of 66 mph.
Visibility below a quarter mile was reported in Tehachapi. Webcams showed very low visibility in the Tehachapi area.
Visibility below a quarter mile was reported in Tehachapi. Webcams showed very low visibility in the Tehachapi area.
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, January 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: 864118, 864668, 864116, 864117.