S. A cold front associated with this system also pushed through the area during the day and brought a period a very strong winds to the Kern County Deserts as well as to the Tehachapi and Lake Isabella area in the Kern County Mountains.
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.
A cold upper low pressure system dropped into northern California during the morning of May 20 carving out a strong upper trough into the western U.S. A cold front associated with this system also pushed through the area during the day and brought a period a very strong winds to the Kern County Deserts as well as to the Tehachapi and Lake Isabella area in the Kern County Mountains. Several stations reported gusts exceeding 60 mph while a few low impact indicator sites briefly measured gusts exceeding 90 mph. Several roads across the impacted area were closed as a precaution between the late morning and the late evening hours of May 20. The winds diminished during the early morning of May 21 as the cold front moved out of the area, leaving an unseasonably cool airmass over the area for a few days. Some instability allowed for some rain and snow showers to develop during the afternoon of May 21 mainly over the Sierra Nevada and adjacent foothills. Precipitation amounts were generally light, mainly up to a quarter inch of liquid precipitation with elevations above 6000 feet picking up at much as 2 inches of new snowfall.
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 May 20, 12:47 AM PST, 5 hours 23 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 147 AM PDT Thu May 20 2021 .SYNOPSIS... A storm system bringing unseasonably cool weather and breezy to strong winds to the district through the end of this week, especially in the wind favored mountain passes and canyon locations. The storm will also bring a chance of showers and thunderstorms to the Sierra from late Thursday through Saturday with the possibility of a few inches of snow above 6,000 feet. && .DISCUSSION... Strong low pressure currently centered over northern California assoicated with a deep trough over the western third of the CONUS. Strong jet circulation around the periphery of the low has brought periods of strong gusty winds, especially in the wind prone areas of the mountain passes and canyons of Kern County. Wind speeds just over 60 mph has been observed over the last two days including the overnight period today. Another period of strong winds will again buffet the area later today beginning late this morning into the afternoon period associated with a 115 knot northerly 300 mb northerly jet that will rotate counter clockwise around the southern periphery of the low pressure center over south central California. Therefore we currently have a high wind warning in effect through 11 PM tonight (Thursday) for parts of the Kern County mountains and pass areas and a wind advisory through 8 PM tonight for the western parts of the San Joaquin Valley and even eastward into the central SJV to address the wind threats. Main impacts to consider would be downed trees and even power lines not to mention damage to any outside structures that are not secured and high profile vehicles traversing roads within the highest winds will make driving conditions rather difficult at times. Moisture is very limited once again with this system but with the anomalously cool center of the low for this time of the year moving further southward into central California Thursday through Saturday. Instability will be increased and chances of showers and even a thunderstorm or two will be possible, mostly in the afternoon time periods and the highest elevations. Thursday the best chances will be in the Sierra Nevada around the Yosemite area south to the Kings Canyon National park. Friday and Saturday the chances will increase southward even into parts of the Tulare County mountains and even the northern parts of the Kern County Mountains, however the further southward and the lower the elevations, the drier it will be and the less likely precipitation would be to occur. On Sunday the system begins to move eastward out of the forecast area and weak Pacific ridging will move into the region bringing drier conditions and a warming trend into the beginning of next week. By Monday, high temperatures will again creep back into the upper 80s and even a few locations into the lower 90s for parts of the SJV and the Kern County desert locations. This looks to remain the case through the middle of the week. Another weak disturbance may move into the region later next week and will look to slightly cool temperatures once again. && .AVIATION... Local wind gusts of 35 knots are possible in the San Joaquin Valley through 03z Friday. Wind gusts of 53 knots or greater are likely through and just below the mountain passes of Kern County during the next 24 hours. A few mountain obscurations over the Sierra Nevada in showers and isolated thunderstorms Thursday and Friday afternoons/early evening. Otherwise, VFR conditions can be expected over the central California interior through at least 06z Friday. && .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 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... High Wind Warning until 11 PM PDT this evening for CAZ196>199. Wind Advisory until 8 PM PDT this evening for CAZ179>189. && public...Andersen aviation....Andersen weather.gov/hanford
8 high wind, 1 strong wind. Local standard time, as filed.
The Southern California Edison Station at Cache Creek measured a peak wind gust of 60 mph.
The Cache Creek CHP station measured a peak wind gust of 58 mph.
NWS Employee reported wind gusts blew a tree into a house in northeast Hanford.
The Jawbone Canyon RAWS measured a peak wind gust of 69 mph.
The Bear Peak RAWS measured a peak wind gust of 67 mph.
The Walker Pass RAWS measured a peak wind gust of 65 mph.
The Indian Wells Canyon RAWS measured a peak wind gust of 91 mph.
The Blue Max RAWS measured a peak wind gust of 65 mph.
The Bird Springs Pass RAWS measured a peak wind gust of 93 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, May 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: 949787, 949786, 949789, 949780, 949783, 949784, 949785, 949781, 949779.