A large upper high pressure ridge built into central California between July 7 and July 9 and remained over the region through July 13 before shifting east and allowing for moderating temperatures across the area by July 14. This ridge was responsible for several days of near record heat across the area and resulted in the most significant hot spell across the area since the heat wave of July…
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 ridge built into central California between July 7 and July 9 and remained over the region through July 13 before shifting east and allowing for moderating temperatures across the area by July 14. This ridge was responsible for several days of near record heat across the area and resulted in the most significant hot spell across the area since the heat wave of July 16-27, 2006. The main saving grace; however, was that humidity was not as high as it was during the 2006 heat wave which lessened it's destructive impact.
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 Jul 7, 1:51 AM PST, 8 hours 9 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 251 AM PDT Wed Jul 7 2021 .SYNOPSIS...A strong ridge of high pressure will build into central California during the next few days and remain in control through at least Tuesday. Excessive heat is likely in the Kern county desert through the period and at elevations below 5000 feet from Friday afternoon through Monday afternoon. && .DISCUSSION...Three heat waves have plagued the central California interior so far this year and it won't be long before another one is upon us. This next heat wave is looking pretty brutal and could bring with it record setting maximum temperatures and possible records for high minimum temperatures this weekend into early next week. Sadly, our next spell of triple digit heat looks like it could be our longest one yet this Summer. Its lengthy duration will most certainly stress heat sensitive individuals and possibly livestock, especially if low temperatures remain above 80 degrees. If the humidity increases a bit this will only worsen the level of discomfort, but humidity trends is something we're less confident as of this writing. In the near term, temperatures, which so far this week have been averaging pretty close to normal over much of our CWA, will remain near seasonable levels again today except in the Kern county desert, which has been baking in triple digit heat practically every day since the 26th of June. The heat wave is already underway there and will expand into the remainder of our CWA by Friday as a strong upper level ridge of high pressure currently centered over the Great Basin builds into central and southern California. The ensembles keep this 600 dm ridge anchored right over central California through at least Tuesday. It's best to think of this ridge as a very tall mountain of dry, stable air. Tall mountains are difficult to move and the ensemble suggest that no weather system will be strong enough to move this mountain of hot, dry air before the middle of next week. While this ridge is centered over us, we can expect skies to remain mostly clear with little more than afternoon cumulus over the highest elevations of the Sierra during the next several days. High temperatures of at least 105 degrees will be widespread in the San Joaquin Valley and lower foothills as early as Thursday. Friday through Monday will surely be hotter with thermometer readings topping 110 degrees in many locations of the valley and lower foothills. In the Kern county desert, afternoon temperatures may approach 120 degrees in the hottest locations Saturday through Monday. As long as this strong area of high pressure remains centered over central California, it will block any northward migration of moisture from the tropics later this week into early next week. Nonetheless, we will be keeping an eye on any westward moving tropical waves across Mexico during this time. It wouldn't take much of a southerly flow to bring monsoonal moisture this far north, but for now we're going to rule that out in the 4 to 7 day period. Otherwise, our next heat wave will peak in intensity this weekend before abating somewhat early next week. Don't let it fool you, though. Tuesday and Wednesday will also be downright hot with high temperatures averaging a good 5 to 8 degrees above normal. .PROBABILISTIC FORECAST...Here is the chance that the high temperature will reach 110 degrees at various locations Friday through Monday: AIRPORT JUNE 9 JUNE 10 JUNE 11 JUNE 12 MCE 5% 25% 25% 10% MAE 10% 33% 25% 18% FAT 26% 40% 50% 38% HJO 25% 38% 63% 50% BFL 18% 25% 50% 38% IYK 85% 93% 95% 95% && .AVIATION... VFR conditions can be expected throughout the central California interior for at least the next 24 hours. && .AIR QUALITY ISSUES... On Wednesday July 7 2021... Unhealthy for sensitive groups in Tulare County 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 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... Excessive Heat Warning from 11 AM this morning to 9 PM PDT Monday for CAZ198-199. Excessive Heat Watch from Friday afternoon through Monday evening for CAZ179>197. && synopsis...Durfee public/aviation/fw...Durfee PIO/IDSS...Dudley weather.gov/hanford
13 excessive heat, 8 heat. Local standard time, as filed.
Daytime highs ranged between 108 and 115 degrees on July 7-9 and between 112 and 120 degrees on July 10-13.
Daytime highs ranged between 108 and 115 degrees on July 7-9 and between 112 and 120 degrees on July 10-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11.
Daytime highs ranged between 107 and 113 degrees on July 9-11.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 107 and 113 degrees on July 9-11 and between 105 and 111 degrees on July 12-13.
Daytime highs ranged between 105 and 110 degrees on July 9-13.
Daytime highs ranged between 105 and 110 degrees on July 9-13.
Daytime highs ranged between 105 and 110 degrees at elevations below 5000 feet on July 9-13.
Daytime highs ranged between 105 and 110 degrees at elevations below 5000 feet on July 9-13.
Daytime highs ranged between 105 and 110 degrees at elevations below 5000 feet on July 9-13.
Daytime highs ranged between 103 and 118 degrees at elevations below 5000 feet on July 9-13.
Daytime highs ranged between 103 and 118 degrees at elevations below 5000 feet on July 9-13.
Daytime highs ranged between 103 and 118 degrees at elevations below 5000 feet on July 9-13.
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, July 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: 960895, 960897, 960911, 960914, 960915, 960916, 960918, 960920, 960921, 960922, 960923, 960925, 960927, 960933, 960935, 960936, 960937, 960938, 960940, 960941, 960942.