Alert archive / California / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in California, 2013
133 severe thunderstorm warnings in 2013. 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 2013. Tap one for its archive.
- Severe Thunderstorm Warnings
- 133
- Busiest month
- August58 severe thunderstorm warnings
- Busiest day
- August 24, 201310 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.
23 of 133 severe thunderstorm warnings covering California in 2013 had a qualifying storm report inside them; 22 of 64 hail, wind and damage reports fell inside a warning, on average 18 minutes after it went out.
California, 2013
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 133 | 23 | 83% | 64 | 34% | 18 min |
Each office's whole area, 2013
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Phoenix, AZ: severe thunderstorm warnings | 59 | 26 | 56% | 65 | 68% | 18 min |
| NWS Los Angeles, CA: severe thunderstorm warnings | 4 | 1 | 75% | 2 | 50% | 19 min |
| NWS San Diego, CA: severe thunderstorm warnings | 24 | 6 | 75% | 22 | 36% | 18 min |
| NWS Hanford, CA: severe thunderstorm warnings | 7 | 0 | 100% | 6 | 0% | |
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 1 | 0 | 100% | 0 | ||
| NWS Medford, OR: severe thunderstorm warnings | 35 | 5 | 86% | 7 | 71% | 21 min |
| NWS Las Vegas, NV: severe thunderstorm warnings | 74 | 14 | 81% | 75 | 49% | 18 min |
| NWS Reno, NV: severe thunderstorm warnings | 46 | 6 | 87% | 31 | 29% | 14 min |
| NWS Sacramento, CA: severe thunderstorm warnings | 16 | 2 | 88% | 4 | 50% | 2 min |
| NWS Eureka, CA: severe thunderstorm warnings | 10 | 0 | 100% | 3 | 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 |
|---|---|---|---|---|
| Feb 19, 3:30 PM PST | Severe Thunderstorm Warning | STO | Glenn | 45 min |
| Mar 31, 6:29 PM PDT | Severe Thunderstorm Warning | STO | San Joaquin | 61 min |
| Mar 31, 7:48 PM PDT | Severe Thunderstorm Warning | MTR | Contra Costa | 12 min |
| Apr 4, 6:29 PM PDT | Severe Thunderstorm Warning | STO | Tehama | 31 min |
| May 5, 1:57 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Plumas, Sierra, Yuba | 33 min |
| May 5, 3:29 PM PDT | Severe Thunderstorm Warning | STO | Butte, Plumas | 46 min |
| May 6, 5:14 PM PDT | Severe Thunderstorm Warning | MFR | Modoc | 31 min |
| May 6, 5:56 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 64 min |
| May 6, 6:34 PM PDT | Severe Thunderstorm Warning | REV | Modoc | 26 min |
| Jun 4, 3:27 PM PDT | Severe Thunderstorm Warning | STO | Tuolumne | 33 min |
| Jun 5, 4:53 PM PDT | Severe Thunderstorm Warning | STO | Alpine, Calaveras, Tuolumne | 37 min |
| Jun 9, 6:51 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 39 min |
| Jun 28, 2:44 PM PDT | Severe Thunderstorm Warning | REV | Alpine | 46 min |
| Jun 28, 4:19 PM PDT | Severe Thunderstorm Warning | REV | Alpine | 26 min |
| Jun 28, 7:53 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 37 min |
| Jul 1, 5:05 PM PDT | Severe Thunderstorm Warning | STO | Alpine, Amador, El Dorado | 25 min |
| Jul 2, 9:14 AM PDT | Severe Thunderstorm Warning | HNX | Kern | 31 min |
| Jul 2, 3:40 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 35 min |
| Jul 2, 3:41 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 34 min |
| Jul 2, 4:34 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 26 min |
| Jul 2, 4:56 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 34 min |
| Jul 2, 10:06 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 24 min |
| Jul 3, 1:59 AM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 46 min |
| Jul 3, 2:21 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 24 min |
| Jul 3, 2:45 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 45 min |
| Jul 3, 3:17 PM PDT | Severe Thunderstorm Warning | STO | Tehama | 43 min |
| Jul 3, 3:28 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 32 min |
| Jul 3, 3:42 PM PDT | Severe Thunderstorm Warning | REV | Mono | 33 min |
| Jul 3, 4:03 PM PDT | Severe Thunderstorm Warning | EKA | Mendocino | 42 min |
| Jul 3, 4:40 PM PDT | Severe Thunderstorm Warning | REV | Placer | 35 min |
| Jul 3, 6:35 PM PDT | Severe Thunderstorm Warning | REV | Sierra | 40 min |
| Jul 3, 7:02 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 28 min |
| Jul 4, 12:38 PM PDT | Severe Thunderstorm Warning | REV | Alpine | 37 min |
| Jul 4, 1:52 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Sierra | 38 min |
| Jul 12, 5:32 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Jul 20, 6:23 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 37 min |
| Jul 20, 8:41 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 34 min |
| Jul 21, 2:51 PM PDT | Severe Thunderstorm Warning | STO | Alpine, Tuolumne | 24 min |
| Jul 22, 2:18 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 57 min |
| Jul 22, 3:23 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 52 min |
| Jul 22, 4:54 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 51 min |
| Jul 22, 4:54 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 66 min |
| Jul 22, 6:57 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 48 min |
| Jul 22, 7:51 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 39 min |
| Jul 25, 2:08 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 52 min |
| Jul 25, 2:24 PM PDT | Severe Thunderstorm Warning | REV | El Dorado, Placer | 36 min |
| Jul 25, 2:43 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Sierra | 32 min |
| Jul 25, 3:53 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Plumas, Sierra | 37 min |
| Jul 25, 5:40 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Plumas | 50 min |
| Jul 25, 6:41 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 49 min |
| Jul 26, 7:19 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 26 min |
| Jul 28, 11:55 AM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 50 min |
| Jul 28, 12:18 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 57 min |
| Jul 28, 12:55 PM PDT | Severe Thunderstorm Warning | REV | Mono | 35 min |
| Jul 28, 1:46 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 44 min |
| Jul 28, 2:12 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Aug 8, 4:55 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 50 min |
| Aug 8, 5:49 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 26 min |
| Aug 8, 6:13 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 47 min |
| Aug 8, 6:19 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 41 min |
| Aug 9, 2:16 PM PDT | Severe Thunderstorm Warning | STO | Glenn, Lake | 44 min |
| Aug 9, 3:32 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 43 min |
| Aug 9, 3:46 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 29 min |
| Aug 9, 4:29 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 46 min |
| Aug 18, 1:35 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 40 min |
| Aug 18, 2:42 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 63 min |
| Aug 18, 2:52 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 23 min |
| Aug 18, 3:06 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 24 min |
| Aug 18, 3:27 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Aug 18, 3:47 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 58 min |
| Aug 18, 4:22 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 23 min |
| Aug 18, 4:44 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 61 min |
| Aug 19, 2:09 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 51 min |
| Aug 19, 3:04 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 26 min |
| Aug 19, 3:30 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 60 min |
| Aug 19, 3:32 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Aug 19, 4:11 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 49 min |
| Aug 19, 4:25 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 50 min |
| Aug 21, 1:16 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 44 min |
| Aug 21, 1:55 PM PDT | Severe Thunderstorm Warning | REV | Alpine, El Dorado | 35 min |
| Aug 21, 2:22 PM PDT | Severe Thunderstorm Warning | EKA | Humboldt, Trinity | 38 min |
| Aug 21, 2:29 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Placer, Sierra | 46 min |
| Aug 21, 2:46 PM PDT | Severe Thunderstorm Warning | STO | Plumas | 44 min |
| Aug 21, 2:56 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 49 min |
| Aug 21, 3:18 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 42 min |
| Aug 21, 3:38 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Plumas, Sierra | 22 min |
| Aug 22, 1:54 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 51 min |
| Aug 22, 2:14 PM PDT | Severe Thunderstorm Warning | MFR | Modoc | 31 min |
| Aug 22, 2:41 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 49 min |
| Aug 22, 3:20 PM PDT | Severe Thunderstorm Warning | REV | Modoc | 40 min |
| Aug 22, 3:32 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 28 min |
| Aug 22, 7:54 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 36 min |
| Aug 23, 2:41 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 34 min |
| Aug 23, 3:34 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 41 min |
| Aug 23, 4:00 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 45 min |
| Aug 24, 12:20 PM PDT | Severe Thunderstorm Warning | VEF | Inyo, San Bernardino | 40 min |
| Aug 24, 12:43 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 62 min |
| Aug 24, 1:16 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 74 min |
| Aug 24, 1:26 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 49 min |
| Aug 24, 1:57 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 63 min |
| Aug 24, 2:06 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 54 min |
| Aug 24, 2:44 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 46 min |
| Aug 24, 2:52 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 53 min |
| Aug 24, 2:57 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 78 min |
| Aug 24, 3:54 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 66 min |
| Aug 25, 4:33 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Aug 28, 3:33 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 57 min |
| Aug 28, 4:20 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 40 min |
| Aug 29, 2:51 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 24 min |
| Aug 29, 7:39 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 36 min |
| Aug 30, 12:19 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 56 min |
| Aug 30, 4:31 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 44 min |
| Aug 31, 12:17 PM PDT | Severe Thunderstorm Warning | PSR | Riverside, San Bernardino | 28 min |
| Aug 31, 4:35 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 40 min |
| Sep 2, 4:34 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 56 min |
| Sep 2, 4:57 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 78 min |
| Sep 2, 6:21 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 54 min |
| Sep 4, 4:15 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 30 min |
| Sep 5, 1:50 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 55 min |
| Sep 5, 2:15 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 60 min |
| Sep 6, 1:11 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 49 min |
| Sep 6, 1:22 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 53 min |
| Sep 6, 2:13 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 47 min |
| Sep 6, 2:33 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 27 min |
| Sep 6, 2:38 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 52 min |
| Sep 7, 12:29 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 46 min |
| Sep 7, 1:10 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 65 min |
| Sep 7, 2:32 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 58 min |
| Sep 7, 3:12 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 63 min |
| Sep 7, 3:29 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 61 min |
| Sep 8, 2:35 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 55 min |
| Sep 8, 6:42 PM PDT | Severe Thunderstorm Warning | VEF | Inyo, San Bernardino | 48 min |
| Sep 9, 6:10 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 65 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- San Bernardino County26
- San Diego County15
- Siskiyou County12
- Riverside County10
- Plumas County9
- Trinity County9
- Sierra County8
- Lassen County8
- Imperial County8
- Alpine County7
- Kern County7
- Inyo County6
- Modoc County4
- Los Angeles County4
- Nevada County3
- Tuolumne County3
- El Dorado County3
- Placer County3
- Glenn County2
- Tehama County2
- Mono County2
- Shasta County2
- San Joaquin County1
- Contra Costa County1
- Yuba County1
- Butte County1
- Calaveras County1
- Amador County1
- Mendocino County1
- Lake County1
- Humboldt County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20122014
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.