Alert archive / California / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in California, 2024
111 severe thunderstorm warnings in 2024. 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 2024. Tap one for its archive.
- Severe Thunderstorm Warnings
- 111
- Busiest month
- September29 severe thunderstorm warnings
- Busiest day
- September 8, 202415 severe thunderstorm warnings
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
20 of 111 severe thunderstorm warnings covering California in 2024 had a qualifying storm report inside them; 29 of 123 hail, wind and damage reports fell inside a warning, on average 20 minutes after it went out.
California, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 111 | 20 | 82% | 123 | 24% | 20 min |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Eureka, CA: severe thunderstorm warnings | 4 | 0 | 100% | 8 | 0% | |
| NWS Hanford, CA: severe thunderstorm warnings | 10 | 1 | 90% | 3 | 33% | 9 min |
| NWS Medford, OR: severe thunderstorm warnings | 11 | 1 | 91% | 13 | 8% | 13 min |
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 6 | 1 | 83% | 37 | 3% | 3 min |
| NWS San Diego, CA: severe thunderstorm warnings | 35 | 4 | 89% | 13 | 46% | 12 min |
| NWS Phoenix, AZ: severe thunderstorm warnings | 140 | 25 | 82% | 57 | 65% | 18 min |
| NWS Sacramento, CA: severe thunderstorm warnings | 10 | 0 | 100% | 1 | 0% | |
| NWS Las Vegas, NV: severe thunderstorm warnings | 34 | 4 | 88% | 36 | 19% | 20 min |
| NWS Los Angeles, CA: severe thunderstorm warnings | 13 | 9 | 31% | 41 | 37% | 24 min |
| NWS Reno, NV: severe thunderstorm warnings | 7 | 0 | 100% | 13 | 0% |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
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 |
|---|---|---|---|---|
| Jan 22, 10:13 AM PST | Severe Thunderstorm Warning | SGX | San Diego | 62 min |
| Jan 22, 10:39 AM PST | Severe Thunderstorm Warning | SGX | San Diego | 36 min |
| Feb 7, 4:28 PM PST | Severe Thunderstorm Warning | LOX | San Luis Obispo, Santa Barbara | 45 min |
| Feb 7, 5:46 PM PST | Severe Thunderstorm Warning | LOX | Santa Barbara | 43 min |
| Feb 7, 6:48 PM PST | Severe Thunderstorm Warning | LOX | Ventura | 49 min |
| Feb 7, 7:22 PM PST | Severe Thunderstorm Warning | LOX | Los Angeles, Ventura | 83 min |
| Feb 7, 10:50 PM PST | Severe Thunderstorm Warning | SGX | Orange, Riverside, San Diego | 38 min |
| Feb 19, 12:00 PM PST | Severe Thunderstorm Warning | HNX | Tulare | 45 min |
| Feb 19, 2:59 PM PST | Severe Thunderstorm Warning | STO | Plumas, Shasta, Tehama | 46 min |
| Feb 19, 3:34 PM PST | Severe Thunderstorm Warning | STO | Butte, Plumas, Tehama | 56 min |
| Feb 19, 3:45 PM PST | Severe Thunderstorm Warning | STO | Butte, Glenn, Plumas, Tehama | 34 min |
| Feb 19, 3:54 PM PST | Severe Thunderstorm Warning | MTR | San Mateo | 22 min |
| Feb 19, 5:37 PM PST | Severe Thunderstorm Warning | STO | El Dorado, Nevada, Placer | 24 min |
| Feb 19, 5:58 PM PST | Severe Thunderstorm Warning | STO | El Dorado, Nevada, Placer | 47 min |
| Feb 19, 9:31 PM PST | Severe Thunderstorm Warning | MTR | Napa | 29 min |
| Feb 20, 5:19 PM PST | Severe Thunderstorm Warning | STO | Butte, Plumas | 42 min |
| Mar 7, 3:33 PM PST | Severe Thunderstorm Warning | LOX | Los Angeles | 42 min |
| Mar 7, 4:17 PM PST | Severe Thunderstorm Warning | LOX | Los Angeles | 58 min |
| Mar 15, 6:07 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 33 min |
| Mar 18, 12:54 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 66 min |
| Mar 24, 3:12 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 63 min |
| Mar 24, 3:42 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 43 min |
| Mar 24, 4:19 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 26 min |
| Mar 29, 3:12 PM PDT | Severe Thunderstorm Warning | MTR | Monterey | 48 min |
| Mar 30, 3:49 PM PDT | Severe Thunderstorm Warning | MTR | Santa Clara | 26 min |
| Mar 30, 4:15 PM PDT | Severe Thunderstorm Warning | MTR | Santa Clara | 45 min |
| Mar 30, 7:19 PM PDT | Severe Thunderstorm Warning | LOX | Santa Barbara | 41 min |
| Mar 30, 8:03 PM PDT | Severe Thunderstorm Warning | LOX | Santa Barbara | 57 min |
| Mar 31, 12:32 AM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 46 min |
| Apr 5, 3:31 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 29 min |
| Apr 19, 4:00 PM PDT | Severe Thunderstorm Warning | HNX | Kern, Tulare | 30 min |
| Jun 6, 6:04 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 41 min |
| Jun 6, 6:16 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 29 min |
| Jun 6, 6:57 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 23 min |
| Jun 8, 4:44 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 31 min |
| Jul 13, 3:11 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 34 min |
| Jul 13, 3:38 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 37 min |
| Jul 13, 3:58 PM PDT | Severe Thunderstorm Warning | HNX | Tuolumne | 32 min |
| Jul 13, 4:01 PM PDT | Severe Thunderstorm Warning | STO | Alpine, Amador, Calaveras, El Dorado, Tuolumne | 44 min |
| Jul 13, 4:23 PM PDT | Severe Thunderstorm Warning | HNX | Mariposa, Tuolumne | 52 min |
| Jul 13, 4:29 PM PDT | Severe Thunderstorm Warning | STO | El Dorado, Placer | 46 min |
| Jul 13, 4:41 PM PDT | Severe Thunderstorm Warning | HNX | Madera, Mariposa | 49 min |
| Jul 14, 1:10 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 50 min |
| Jul 14, 1:27 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 48 min |
| Jul 14, 1:52 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 38 min |
| Jul 14, 2:10 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 50 min |
| Jul 14, 2:21 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 39 min |
| Jul 14, 2:58 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 34 min |
| Jul 15, 1:53 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 52 min |
| Jul 15, 3:02 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 43 min |
| Jul 15, 4:02 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 43 min |
| Jul 22, 2:09 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 51 min |
| Jul 22, 2:58 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 32 min |
| Jul 22, 3:41 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 49 min |
| Jul 23, 2:29 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 61 min |
| Jul 23, 3:03 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 42 min |
| Jul 24, 2:33 PM PDT | Severe Thunderstorm Warning | HNX | Mariposa, Tuolumne | 27 min |
| Jul 24, 2:58 PM PDT | Severe Thunderstorm Warning | HNX | Tuolumne | 32 min |
| Jul 24, 3:22 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 21 min |
| Jul 24, 3:28 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 47 min |
| Jul 31, 5:25 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 19 min |
| Aug 1, 4:33 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 57 min |
| Aug 1, 5:22 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 53 min |
| Aug 1, 5:29 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 61 min |
| Aug 1, 5:42 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 48 min |
| Aug 1, 6:27 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 33 min |
| Aug 2, 3:23 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 52 min |
| Aug 10, 5:21 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 39 min |
| Aug 11, 1:02 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 58 min |
| Aug 11, 1:53 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 67 min |
| Aug 11, 3:44 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 15 min |
| Aug 11, 8:27 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Aug 17, 1:03 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 27 min |
| Aug 17, 1:05 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 25 min |
| Aug 17, 2:36 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 22 min |
| Aug 17, 2:48 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 27 min |
| Aug 17, 3:11 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 34 min |
| Aug 17, 3:30 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 30 min |
| Aug 17, 4:07 PM PDT | Severe Thunderstorm Warning | STO | Shasta, Tehama | 38 min |
| Aug 17, 4:43 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 47 min |
| Aug 21, 4:57 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Sep 7, 1:51 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 54 min |
| Sep 7, 2:33 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Sep 7, 2:34 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 56 min |
| Sep 7, 2:36 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 19 min |
| Sep 7, 2:47 PM PDT | Severe Thunderstorm Warning | PSR | Riverside, San Bernardino | 28 min |
| Sep 7, 3:10 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 32 min |
| Sep 7, 3:24 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 36 min |
| Sep 7, 3:30 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 45 min |
| Sep 7, 3:34 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 41 min |
| Sep 7, 3:40 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 50 min |
| Sep 7, 3:40 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 35 min |
| Sep 7, 4:18 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Sep 7, 4:25 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 50 min |
| Sep 7, 4:29 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 46 min |
| Sep 7, 5:10 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 35 min |
| Sep 7, 10:02 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 28 min |
| Sep 7, 10:30 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 45 min |
| Sep 8, 1:09 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 51 min |
| Sep 8, 1:27 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 6 min |
| Sep 8, 1:27 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 63 min |
| Sep 8, 1:34 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 41 min |
| Sep 8, 2:04 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 56 min |
| Sep 8, 2:24 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 18 min |
| Sep 8, 2:27 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 48 min |
| Sep 8, 2:58 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 47 min |
| Sep 8, 3:10 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 50 min |
| Sep 8, 4:22 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 53 min |
| Sep 8, 4:25 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 35 min |
| Sep 8, 4:50 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 55 min |
| Dec 14, 1:25 PM PST | Severe Thunderstorm Warning | MTR | Santa Cruz | 23 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Riverside County30
- San Diego County20
- San Bernardino County16
- Los Angeles County8
- Plumas County5
- Siskiyou County5
- Tuolumne County5
- Imperial County5
- Santa Barbara County4
- Tehama County4
- El Dorado County4
- Trinity County4
- Shasta County3
- Butte County3
- Placer County3
- Fresno County3
- Mariposa County3
- Ventura County2
- Tulare County2
- Nevada County2
- Santa Clara County2
- San Luis Obispo County1
- Orange County1
- Glenn County1
- San Mateo County1
- Napa County1
- Monterey County1
- Kern County1
- Lassen County1
- Alpine County1
- Amador County1
- Calaveras County1
- Madera County1
- Inyo County1
- Santa Cruz County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20232025
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.