Alert archive / California / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in California, 2014
104 severe thunderstorm warnings in 2014. 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 2014. Tap one for its archive.
- Severe Thunderstorm Warnings
- 104
- Busiest month
- August42 severe thunderstorm warnings
- Busiest day
- August 11, 20147 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.
21 of 104 severe thunderstorm warnings covering California in 2014 had a qualifying storm report inside them; 22 of 95 hail, wind and damage reports fell inside a warning, on average 17 minutes after it went out.
California, 2014
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 104 | 21 | 80% | 95 | 23% | 17 min |
Each office's whole area, 2014
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS San Diego, CA: severe thunderstorm warnings | 10 | 5 | 50% | 33 | 18% | 17 min |
| NWS Los Angeles, CA: severe thunderstorm warnings | 3 | 1 | 67% | 4 | 25% | 5 min |
| NWS Medford, OR: severe thunderstorm warnings | 31 | 1 | 97% | 4 | 25% | 32 min |
| NWS Las Vegas, NV: severe thunderstorm warnings | 49 | 12 | 76% | 69 | 42% | 21 min |
| NWS Reno, NV: severe thunderstorm warnings | 35 | 8 | 77% | 31 | 35% | 15 min |
| NWS Hanford, CA: severe thunderstorm warnings | 7 | 1 | 86% | 4 | 25% | 9 min |
| NWS Eureka, CA: severe thunderstorm warnings | 6 | 1 | 83% | 8 | 25% | 4 min |
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 3 | 0 | 100% | 6 | 0% | |
| NWS Sacramento, CA: severe thunderstorm warnings | 13 | 3 | 77% | 9 | 33% | 21 min |
| NWS Phoenix, AZ: severe thunderstorm warnings | 82 | 24 | 71% | 98 | 61% | 17 min |
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 28, 11:53 AM PST | Severe Thunderstorm Warning | HNX | Fresno | 37 min |
| Feb 28, 12:39 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Kings, Tulare | 36 min |
| Feb 28, 1:01 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Tulare | 29 min |
| Feb 28, 1:12 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Tulare | 33 min |
| Feb 28, 4:26 PM PST | Severe Thunderstorm Warning | SGX | San Diego | 49 min |
| Mar 1, 3:15 AM PST | Severe Thunderstorm Warning | LOX | Los Angeles | 45 min |
| Apr 25, 2:51 PM PDT | Severe Thunderstorm Warning | HNX | Fresno, Kings, Tulare | 39 min |
| Apr 25, 3:25 PM PDT | Severe Thunderstorm Warning | HNX | Fresno, Kings, Tulare | 35 min |
| Apr 25, 3:57 PM PDT | Severe Thunderstorm Warning | HNX | Tulare | 33 min |
| May 19, 2:29 PM PDT | Severe Thunderstorm Warning | STO | Glenn, Tehama | 46 min |
| May 22, 3:34 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 41 min |
| May 22, 4:10 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 65 min |
| Jul 2, 5:53 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 22 min |
| Jul 5, 11:09 AM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 34 min |
| Jul 5, 6:54 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 36 min |
| Jul 8, 5:51 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 39 min |
| Jul 8, 6:27 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Jul 9, 4:34 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 26 min |
| Jul 9, 4:43 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 47 min |
| Jul 9, 6:02 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 28 min |
| Jul 14, 3:02 PM PDT | Severe Thunderstorm Warning | REV | Mono | 43 min |
| Jul 14, 3:27 PM PDT | Severe Thunderstorm Warning | REV | Mono | 33 min |
| Jul 14, 4:45 PM PDT | Severe Thunderstorm Warning | STO | Tuolumne | 60 min |
| Jul 17, 1:20 PM PDT | Severe Thunderstorm Warning | REV | Alpine | 31 min |
| Jul 17, 3:17 PM PDT | Severe Thunderstorm Warning | REV | Nevada, Placer | 43 min |
| Jul 17, 5:18 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 42 min |
| Jul 17, 6:58 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Sierra | 47 min |
| Jul 17, 7:55 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Plumas | 50 min |
| Jul 18, 12:33 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 57 min |
| Jul 18, 3:44 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 61 min |
| Jul 18, 5:59 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Plumas | 61 min |
| Jul 19, 2:45 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 45 min |
| Jul 19, 3:06 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 39 min |
| Jul 19, 7:44 PM PDT | Severe Thunderstorm Warning | STO | Plumas | 31 min |
| Jul 20, 2:55 PM PDT | Severe Thunderstorm Warning | MTR | San Benito | 55 min |
| Jul 20, 3:23 PM PDT | Severe Thunderstorm Warning | REV | Placer | 37 min |
| Jul 22, 3:54 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 36 min |
| Jul 22, 4:15 PM PDT | Severe Thunderstorm Warning | STO | Shasta, Tehama | 60 min |
| Jul 22, 4:35 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 25 min |
| Jul 22, 4:37 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 23 min |
| Jul 22, 4:58 PM PDT | Severe Thunderstorm Warning | EKA | Humboldt, Trinity | 32 min |
| Jul 22, 5:18 PM PDT | Severe Thunderstorm Warning | EKA | Trinity | 27 min |
| Jul 28, 6:02 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Aug 1, 1:58 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 62 min |
| Aug 1, 3:47 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Aug 1, 4:16 PM PDT | Severe Thunderstorm Warning | REV | Mono | 44 min |
| Aug 3, 1:00 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 45 min |
| Aug 3, 1:36 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 39 min |
| Aug 3, 2:18 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 42 min |
| Aug 3, 2:38 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 67 min |
| Aug 3, 4:33 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Aug 3, 5:07 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 53 min |
| Aug 4, 7:13 PM PDT | Severe Thunderstorm Warning | MFR | Modoc, Siskiyou | 30 min |
| Aug 4, 8:41 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 34 min |
| Aug 4, 8:47 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 20 min |
| Aug 6, 4:52 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 38 min |
| Aug 7, 7:04 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 26 min |
| Aug 10, 3:43 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 47 min |
| Aug 10, 3:49 PM PDT | Severe Thunderstorm Warning | REV | El Dorado, Placer | 56 min |
| Aug 11, 2:07 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 53 min |
| Aug 11, 2:17 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 43 min |
| Aug 11, 2:59 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 46 min |
| Aug 11, 3:09 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 51 min |
| Aug 11, 3:38 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 36 min |
| Aug 11, 3:53 PM PDT | Severe Thunderstorm Warning | STO | Sierra | 39 min |
| Aug 11, 4:44 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Placer, Sierra | 61 min |
| Aug 11, 5:37 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 23 min |
| Aug 11, 5:42 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 33 min |
| Aug 11, 5:49 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 56 min |
| Aug 11, 6:13 PM PDT | Severe Thunderstorm Warning | REV | Plumas | 32 min |
| Aug 11, 6:43 PM PDT | Severe Thunderstorm Warning | STO | Plumas | 33 min |
| Aug 12, 1:37 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 53 min |
| Aug 12, 4:05 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 40 min |
| Aug 17, 9:00 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 27 min |
| Aug 18, 2:30 PM PDT | Severe Thunderstorm Warning | VEF | Inyo, San Bernardino | 30 min |
| Aug 18, 3:20 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 25 min |
| Aug 18, 4:10 PM PDT | Severe Thunderstorm Warning | VEF | Inyo, San Bernardino | 50 min |
| Aug 19, 2:07 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 53 min |
| Aug 20, 8:31 AM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 59 min |
| Aug 21, 12:18 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Aug 21, 12:30 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 60 min |
| Aug 21, 1:19 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 56 min |
| Aug 21, 1:54 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 66 min |
| Aug 21, 2:14 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 46 min |
| Aug 21, 3:15 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 34 min |
| Sep 7, 1:58 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 47 min |
| Sep 14, 3:43 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 62 min |
| Sep 16, 1:39 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 51 min |
| Sep 16, 2:29 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Diego | 61 min |
| Sep 16, 3:29 PM PDT | Severe Thunderstorm Warning | SGX | Orange, Riverside, San Bernardino, San Diego | 91 min |
| Sep 16, 3:58 PM PDT | Severe Thunderstorm Warning | PSR | Riverside, San Bernardino | 47 min |
| Sep 25, 5:59 PM PDT | Severe Thunderstorm Warning | STO | Shasta | 46 min |
| Sep 26, 2:25 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 65 min |
| Sep 26, 2:41 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 64 min |
| Sep 26, 2:57 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 63 min |
| Sep 26, 3:20 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 55 min |
| Sep 26, 3:33 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 57 min |
| Sep 26, 5:32 PM PDT | Severe Thunderstorm Warning | MTR | Napa | 28 min |
| Sep 26, 6:52 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 23 min |
| Sep 27, 7:03 AM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Oct 25, 5:23 PM PDT | Severe Thunderstorm Warning | STO | Shasta, Tehama | 52 min |
| Dec 7, 3:11 PM PST | Severe Thunderstorm Warning | EKA | Humboldt | 17 min |
| Dec 11, 4:38 AM PST | Severe Thunderstorm Warning | EKA | Humboldt, Mendocino | 24 min |
| Dec 16, 8:27 PM PST | Severe Thunderstorm Warning | MTR | Monterey, Santa Cruz | 28 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- San Bernardino County23
- Plumas County13
- Siskiyou County11
- Imperial County10
- Riverside County10
- Sierra County9
- Fresno County6
- Tulare County6
- San Diego County6
- Shasta County6
- Placer County4
- Trinity County4
- Kings County3
- Los Angeles County3
- Tehama County3
- Mono County3
- Nevada County3
- Lassen County3
- Humboldt County3
- Inyo County2
- Glenn County1
- Tuolumne County1
- Alpine County1
- San Benito County1
- Modoc County1
- El Dorado County1
- Orange County1
- Napa County1
- Mendocino County1
- Monterey County1
- Santa Cruz County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20132015
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.