Alert archive / California / Severe Thunderstorm Warnings
Severe Thunderstorm Warnings in California, 2008
92 severe thunderstorm warnings in 2008. 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 2008. Tap one for its archive.
- Severe Thunderstorm Warnings
- 92
- Busiest month
- August24 severe thunderstorm warnings
- Busiest day
- May 22, 20086 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.
10 of 92 severe thunderstorm warnings covering California in 2008 had a qualifying storm report inside them; 8 of 29 hail, wind and damage reports fell inside a warning, on average 22 minutes after it went out.
California, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Severe thunderstorm warnings | 92 | 10 | 89% | 29 | 28% | 22 min |
Each office's whole area, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 3 | 0 | 100% | 1 | 0% | |
| NWS Los Angeles, CA: severe thunderstorm warnings | 8 | 0 | 100% | 1 | 0% | |
| NWS Hanford, CA: severe thunderstorm warnings | 16 | 4 | 75% | 10 | 50% | 18 min |
| NWS San Diego, CA: severe thunderstorm warnings | 12 | 2 | 83% | 6 | 50% | 29 min |
| NWS Reno, NV: severe thunderstorm warnings | 46 | 2 | 96% | 18 | 28% | 20 min |
| NWS Phoenix, AZ: severe thunderstorm warnings | 141 | 25 | 82% | 52 | 71% | 22 min |
| NWS Medford, OR: severe thunderstorm warnings | 6 | 0 | 100% | 2 | 0% | |
| NWS Sacramento, CA: severe thunderstorm warnings | 1 | 0 | 100% | 1 | 0% | |
| NWS Las Vegas, NV: severe thunderstorm warnings | 64 | 5 | 92% | 24 | 42% | 29 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 |
|---|---|---|---|---|
| Jan 23, 5:37 PM PST | Severe Thunderstorm Warning | LOX | Los Angeles | 23 min |
| Jan 27, 9:30 AM PST | Severe Thunderstorm Warning | LOX | Santa Barbara | 30 min |
| Jan 27, 11:21 AM PST | Severe Thunderstorm Warning | LOX | Santa Barbara | 24 min |
| Jan 27, 12:05 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Kings, Tulare | 25 min |
| Jan 27, 12:26 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Tulare | 34 min |
| Jan 27, 3:28 PM PST | Severe Thunderstorm Warning | LOX | Los Angeles | 47 min |
| Jan 27, 4:17 PM PST | Severe Thunderstorm Warning | HNX | Tulare | 43 min |
| Feb 20, 12:08 PM PST | Severe Thunderstorm Warning | HNX | Kern | 37 min |
| Feb 20, 12:30 PM PST | Severe Thunderstorm Warning | HNX | Kern | 45 min |
| Feb 22, 12:46 PM PST | Severe Thunderstorm Warning | HNX | Kern | 29 min |
| Mar 15, 5:22 PM PDT | Severe Thunderstorm Warning | HNX | Fresno, Madera | 23 min |
| Mar 15, 5:42 PM PDT | Severe Thunderstorm Warning | MTR | San Benito | 48 min |
| Mar 15, 6:02 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 28 min |
| Mar 15, 6:15 PM PDT | Severe Thunderstorm Warning | MTR | Monterey, San Benito | 30 min |
| Mar 15, 6:49 PM PDT | Severe Thunderstorm Warning | MTR | Monterey | 41 min |
| May 4, 5:21 PM PDT | Severe Thunderstorm Warning | STO | Nevada, Placer, Sutter, Yuba | 39 min |
| May 22, 12:05 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 40 min |
| May 22, 1:00 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 45 min |
| May 22, 2:03 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 57 min |
| May 22, 3:00 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 60 min |
| May 22, 3:46 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 44 min |
| May 22, 4:29 PM PDT | Severe Thunderstorm Warning | SGX | Riverside, San Bernardino | 46 min |
| May 27, 10:50 AM PDT | Severe Thunderstorm Warning | REV | Mono | 25 min |
| Jun 21, 4:45 PM PDT | Severe Thunderstorm Warning | REV | Modoc | 30 min |
| Jun 28, 6:03 PM PDT | Severe Thunderstorm Warning | MFR | Siskiyou | 24 min |
| Jun 29, 3:27 PM PDT | Severe Thunderstorm Warning | REV | Lassen, Plumas | 48 min |
| Jun 29, 5:07 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 53 min |
| Jun 29, 5:12 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 33 min |
| Jun 29, 5:45 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 45 min |
| Jun 29, 6:29 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 46 min |
| Jun 29, 8:09 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 35 min |
| Jul 10, 2:59 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 46 min |
| Jul 10, 4:10 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 50 min |
| Jul 10, 5:09 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 66 min |
| Jul 10, 6:17 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Jul 10, 7:52 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 38 min |
| Jul 10, 9:33 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 42 min |
| Jul 10, 9:48 PM PDT | Severe Thunderstorm Warning | SGX | San Bernardino | 72 min |
| Jul 12, 2:08 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 39 min |
| Jul 12, 2:42 PM PDT | Severe Thunderstorm Warning | HNX | Tulare | 63 min |
| Jul 12, 3:51 PM PDT | Severe Thunderstorm Warning | HNX | Kern, Tulare | 54 min |
| Jul 12, 4:31 PM PDT | Severe Thunderstorm Warning | REV | El Dorado | 29 min |
| Jul 12, 4:40 PM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 51 min |
| Jul 12, 6:16 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 29 min |
| Jul 12, 6:19 PM PDT | Severe Thunderstorm Warning | VEF | Inyo | 26 min |
| Jul 12, 8:10 PM PDT | Severe Thunderstorm Warning | HNX | Kern | 50 min |
| Jul 21, 5:22 PM PDT | Severe Thunderstorm Warning | REV | Mono | 38 min |
| Jul 21, 7:34 PM PDT | Severe Thunderstorm Warning | REV | Modoc | 41 min |
| Aug 3, 3:04 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 41 min |
| Aug 3, 3:16 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 44 min |
| Aug 3, 4:01 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 44 min |
| Aug 3, 4:41 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 49 min |
| Aug 4, 1:30 PM PDT | Severe Thunderstorm Warning | PSR | Riverside, San Bernardino | 60 min |
| Aug 4, 1:44 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 46 min |
| Aug 4, 2:53 PM PDT | Severe Thunderstorm Warning | SGX | Riverside | 52 min |
| Aug 4, 3:27 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 48 min |
| Aug 4, 4:01 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 59 min |
| Aug 7, 3:58 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 62 min |
| Aug 7, 4:16 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 59 min |
| Aug 8, 4:17 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 58 min |
| Aug 8, 5:03 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 57 min |
| Aug 8, 5:48 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 57 min |
| Aug 17, 2:59 PM PDT | Severe Thunderstorm Warning | REV | Plumas, Sierra | 46 min |
| Aug 17, 5:25 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 35 min |
| Aug 17, 6:02 PM PDT | Severe Thunderstorm Warning | REV | Lassen | 43 min |
| Aug 25, 1:52 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 38 min |
| Aug 25, 2:31 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 74 min |
| Aug 25, 2:55 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 80 min |
| Aug 25, 4:12 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 33 min |
| Aug 25, 5:47 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 43 min |
| Aug 25, 8:04 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 41 min |
| Aug 25, 9:30 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 60 min |
| Aug 31, 5:30 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 45 min |
| Aug 31, 6:14 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 46 min |
| Aug 31, 6:29 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 28 min |
| Sep 9, 5:38 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 21 min |
| Sep 10, 12:59 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 46 min |
| Sep 10, 3:05 PM PDT | Severe Thunderstorm Warning | PSR | Imperial, Riverside | 55 min |
| Sep 11, 11:45 AM PDT | Severe Thunderstorm Warning | PSR | Imperial | 37 min |
| Sep 11, 2:06 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 54 min |
| Sep 11, 2:54 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 42 min |
| Sep 11, 3:31 PM PDT | Severe Thunderstorm Warning | PSR | Riverside | 44 min |
| Sep 11, 4:29 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 61 min |
| Sep 17, 2:54 PM PDT | Severe Thunderstorm Warning | SGX | San Diego | 36 min |
| Sep 17, 3:23 PM PDT | Severe Thunderstorm Warning | VEF | San Bernardino | 37 min |
| Sep 17, 6:12 PM PDT | Severe Thunderstorm Warning | PSR | Imperial | 48 min |
| Nov 1, 7:51 AM PDT | Severe Thunderstorm Warning | LOX | Los Angeles | 49 min |
| Nov 1, 7:17 PM PDT | Severe Thunderstorm Warning | HNX | Tulare | 58 min |
| Dec 15, 12:15 PM PST | Severe Thunderstorm Warning | HNX | Tulare | 60 min |
| Dec 15, 1:11 PM PST | Severe Thunderstorm Warning | HNX | Tulare | 34 min |
| Dec 15, 1:31 PM PST | Severe Thunderstorm Warning | HNX | Fresno, Madera | 44 min |
| Dec 15, 6:42 PM PST | Severe Thunderstorm Warning | HNX | Kings, Tulare | 48 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- San Bernardino County25
- Riverside County12
- Imperial County12
- Tulare County9
- Lassen County8
- San Diego County7
- Los Angeles County6
- Kern County6
- Fresno County4
- Santa Barbara County2
- Kings County2
- Madera County2
- San Benito County2
- Monterey County2
- Mono County2
- Modoc County2
- Plumas County2
- Nevada County1
- Placer County1
- Sutter County1
- Yuba County1
- Siskiyou County1
- El Dorado County1
- Inyo County1
- Sierra County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20072009
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.