A large upper high pressure center over the Desert Southwest region built northward and westward on August 14 and maintained it's grip over central California for nearly a week resulting in oppressive heat over the area for several days. An Excessive Heat Warning was posted for the San Joaquin Valley and Sierra Foothills for five days and for the Kern County Deserts for seven days as high…
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 large upper high pressure center over the Desert Southwest region built northward and westward on August 14 and maintained it's grip over central California for nearly a week resulting in oppressive heat over the area for several days. An Excessive Heat Warning was posted for the San Joaquin Valley and Sierra Foothills for five days and for the Kern County Deserts for seven days as high temperatures neared record levels. In fact, several new records were set for both afternoon high temperatures and overnight high minimum temperatures in the San Joaquin Valley on August 16 and 17 with several locations reporting highs above 110 degrees F and lows above 80 degrees F. Several cities and towns in the San Joaquin Valley, Sierra Foothills and Kern County Deserts opened their cooling centers each afternoon during this heat wave. Local emergencies were declared in Fresno, Tulare and Kings Counties due to an unusually high rate of livestock fatalities which took place between August 14 and August 18. The large high finally loosened it's grip on the area on August 21 while a northwesterly flow brought slightly cooler air into the area.
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 Aug 14, 3:02 AM PST, 6 hours 58 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 402 AM PDT Fri Aug 14 2020 .SYNOPSIS...Dangerously hot temperatures are expected for the weekend and into the majority of next week as a high pressure strengthens over the Great Basin. Afternoon t-storms are also possible for the higher elevations of the Sierra each day through at least Tuesday. && .DISCUSSION...Current temperatures across the valley are 5 to 10 degrees warmer compared to this time yesterday. This is due to a fair amount of mid and upper level cloud cover from the remnants of Elida pushing northward through the district. Clouds will continue to dissipate this morning as our high temperatures begin to really ramp up this afternoon. With ample mid-level moisture and steep mid level lapse rates, there is a slight chance of afternoon showers and t-storms across the higher elevations of the Sierra. The major story for our area starting today and going into a majority of next week will be dangerous heat across the central California interior. Deterministic models, as well as their respective ensemble solutions are all indicating that a very strong high pressure will remain situated over the central Great Basin through next week, with only some minor weakening by next Thursday and Friday. Afternoon high temperatures from today through next Friday will range from 102 to 112 in the Southern San Joaquin Valley, West Side Hills, lower elevations of the Sierra foothills, and Kern County desert. Afternoon temperatures up to 115 degrees are conceivable each day in the Indian Wells Valley. Low temperatures will also remain very warm during this period, with overnight readings in the 70s and low 80s in warmer locations. For this reason, an Excessive Heat Warning will be in effect from this afternoon through at least next Wednesday. Models are also indicating that mid-level moisture will continue to rotate northward around the periphery of the high pressure. Combined with mid-level instability will lead to a daily chance of afternoon t-storms for the higher elevations of the Southern Sierra through at least Tuesday. && .AVIATION... Isolated thunderstorms are possible over the higher elevations of the Southern Sierra Nevada through 03z Friday. Otherwise, VFR conditions will prevail elsewhere over the central California interior during the next 24 hours. && .AIR QUALITY ISSUES... On Friday August 14 2020... Unhealthy for sensitive groups in Fresno and Kern Counties and Sequoia National Park and Forest. 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... Excessive Heat Warning from noon today to 9 PM PDT Wednesday for CAZ179>191-198-199. && public...CMC aviation....CMC weather.gov/hanford
15 excessive heat. Local standard time, as filed.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 104 and 109 degrees on August 14-15 and August 18 and between 107 and 112 degrees on August 16-17.
Daytime highs ranged between 102 and 107 degrees on August 14-15 and August 18 and between 105 and 110 degrees on August 16-17.
Daytime highs ranged between 102 and 107 degrees on August 14-15 and August 18 and between 105 and 110 degrees on August 16-17.
Daytime highs ranged between 108 and 113 degrees on August 14-15 and August 18-20 between 110 and 115 degrees on August 16-17.
Daytime highs ranged between 108 and 113 degrees on August 14-15 and August 18-20 between 110 and 115 degrees on August 16-17.
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, August 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: 902589, 902590, 902591, 902592, 902594, 902595, 902596, 902597, 902598, 902600, 902601, 902602, 902603, 902604, 902605.