Alert archive / California / Severe Thunderstorm Warnings / 2020
Severe Thunderstorm Warnings in California, August 2020
20 severe thunderstorm warnings in August 2020. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of severe thunderstorm warnings reaches back to 1986.
Severe Thunderstorm Warnings by county
Each county as a circle sized by its count in August 2020. Tap one for its archive.
- Severe Thunderstorm Warnings
- 20
- Busiest day
- August 18, 20207 severe thunderstorm warnings
Over time
By day
Days in UTC, the clock the archive keeps.
The alerts
Every alert, in the order issued. Times are local, Pacific Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 5, 2:59 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 31 min |
| Aug 11, 12:50 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 55 min |
| Aug 15, 2:24 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 55 min |
| Aug 15, 4:08 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 37 min |
| Aug 16, 2:41 AM PDT | Severe Thunderstorm Warning | MTR | Alameda, Monterey, San Benito, City and County of San Francisco, San Mateo, Santa Clara and 1 more | 94 min |
| Aug 16, 3:55 AM PDT | Severe Thunderstorm Warning | MTR | Alameda, Contra Costa, Marin, Monterey, Napa, City and County of San Francisco and 4 more | 80 min |
| Aug 16, 5:14 AM PDT | Severe Thunderstorm Warning | MTR | Alameda, Contra Costa, Marin, Napa, City and County of San Francisco, San Mateo and 3 more | 91 min |
| Aug 16, 6:37 AM PDT | Severe Thunderstorm Warning | MTR | Alameda, Contra Costa, Marin, Monterey, Napa, City and County of San Francisco and 4 more | 83 min |
| Aug 17, 5:05 PM PDT | Severe Thunderstorm Warning | HNX | Fresno, Madera, Mariposa, Tuolumne | 55 min |
| Aug 17, 6:11 PM PDT | Severe Thunderstorm Warning | HNX | Mariposa, Tuolumne | 34 min |
| Aug 18, 12:28 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 46 min |
| Aug 18, 12:54 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 66 min |
| Aug 18, 1:57 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 39 min |
| Aug 18, 3:12 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 21 min |
| Aug 18, 3:45 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 45 min |
| Aug 21, 1:21 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 26 min |
| Aug 21, 1:37 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 25 min |
| Aug 22, 2:00 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 45 min |
| Aug 22, 2:21 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 54 min |
| Aug 22, 4:13 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 47 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Riverside County5
- San Bernardino County5
- Alameda County4
- City and County of San Francisco4
- San Mateo County4
- Santa Clara County4
- Santa Cruz County4
- Monterey County3
- Contra Costa County3
- Marin County3
- Napa County3
- Sonoma County3
- Lassen County2
- San Diego County2
- Mariposa County2
- Tuolumne County2
- Siskiyou County1
- San Benito County1
- Fresno County1
- Madera County1
Nearby
Alerts in force nowTornadoes on recordThe radar archive20192021
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.