Alert archive / California / Alameda County
Weather alerts in Alameda County, California, 2024
102 weather alerts in 2024, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Alameda County and its neighbors
Each county as a circle sized by its count in 2024. Tap one for its archive.
- Alerts
- 102
- Warnings
- 15
- Watches
- 5
- Advisories
- 75
- Busiest month
- December19 alerts
- Busiest day
- December 29, 20244 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Alameda County, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 0 | 1 | 0% | |||
| Flash flood warnings | 2 | 1 | 50% | 1 | 100% | 63 min |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS San Francisco Bay Area, CA: tornado warnings | 4 | 0 | 100% | 1 | 0% | |
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 6 | 1 | 83% | 37 | 3% | 3 min |
| NWS San Francisco Bay Area, CA: flash flood warnings | 6 | 1 | 83% | 83 | 1% | 63 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 | Lasted |
|---|---|---|---|
| Jan 2, 2:08 AM PST | Dense Fog Advisory | MTR | 8 hr |
| Jan 5, 11:14 AM PST | Frost Advisory | MTR | 47 hr |
| Jan 6, 2:25 PM PST | Frost Advisory | MTR | 44 hr |
| Jan 9, 11:08 AM PST | Coastal Flood Advisory | MTR | 24 hr |
| Jan 10, 4:40 AM PST | Frost Advisory | MTR | 29 hr |
| Jan 10, 10:37 AM PST | Coastal Flood Advisory | MTR | 25 hr |
| Jan 11, 9:42 AM PST | Frost Advisory | MTR | 24 hr |
| Jan 11, 11:43 AM PST | Coastal Flood Advisory | MTR | 25 hr |
| Jan 20, 6:31 PM PST | Coastal Flood Advisory | MTR | 40 hr |
| Jan 22, 7:53 AM PST | Areal Flood Warning | MTR | 5 hr |
| Jan 22, 12:55 PM PST | Coastal Flood Advisory | MTR | 23 hr |
| Jan 29, 12:20 PM PST | Wind Advisory | MTR | 61 hr |
| Jan 29, 12:41 PM PST | Flood Watch | MTR | 3 days |
| Jan 30, 12:35 AM PST | High Wind Warning | MTR | 49 hr |
| Jan 31, 8:53 PM PST | Areal Flood Advisory | MTR | 5 hr |
| Jan 31, 10:06 PM PST | Areal Flood Advisory | MTR | 5 hr |
| Feb 1, 12:04 AM PST | Areal Flood Advisory | MTR | 3 hr |
| Feb 2, 1:40 AM PST | Flood Watch | MTR | 3 days |
| Feb 2, 1:45 AM PST | High Wind Warning | MTR | 3 days |
| Feb 2, 1:45 AM PST | Wind Advisory | MTR | 3 days |
| Feb 4, 12:02 PM PST | Areal Flood Warning | MTR | 20 hr |
| Feb 4, 1:21 PM PST | Coastal Flood Advisory | MTR | 20 hr |
| Feb 4, 2:05 PM PST | Special Weather Statement | MTR | 25 min |
| Feb 5, 3:21 PM PST | Coastal Flood Advisory | MTR | 5 days |
| Feb 8, 12:24 PM PST | Frost Advisory | MTR | 21 hr |
| Feb 16, 10:06 AM PST | Flood Watch | MTR | 4 days |
| Feb 17, 2:48 AM PST | Wind Advisory | MTR | 3 days |
| Feb 18, 6:58 PM PST | Areal Flood Advisory | MTR | 6 hr |
| Feb 18, 9:39 PM PST | Areal Flood Advisory | MTR | 3 hr |
| Feb 20, 2:35 PM PST | Areal Flood Advisory | MTR | 2 hr |
| Feb 21, 4:58 AM PST | Dense Fog Advisory | MTR | 5 hr |
| Feb 29, 9:17 AM PST | Wind Advisory | MTR | 47 hr |
| Mar 1, 4:57 PM PST | Special Weather Statement | MTR | 18 min |
| Mar 1, 10:00 PM PST | Areal Flood Advisory | MTR | 6 hr |
| Mar 6, 1:15 PM PST | Areal Flood Advisory | MTR | 3 hr |
| Mar 6, 2:10 PM PST | Areal Flood Advisory | MTR | 5 hr |
| Mar 12, 1:02 PM PDT | Wind Advisory | MTR | 70 hr |
| Mar 28, 2:05 AM PDT | Wind Advisory | MTR | 44 hr |
| Mar 30, 1:54 PM PDT | Special Weather Statement | MTR | 36 min |
| Mar 30, 6:04 PM PDT | Areal Flood Advisory | MTR | 116 min |
| Apr 5, 12:46 AM PDT | Frost Advisory | MTR | 32 hr |
| Apr 5, 4:35 PM PDT | Special Weather Statement | MTR | 25 min |
| Apr 5, 4:50 PM PDT | Special Weather Statement | MTR | 25 min |
| Apr 5, 5:14 PM PDT | Special Weather Statement | MTR | 31 min |
| May 4, 9:03 AM PDT | Special Weather Statement | MTR | 87 min |
| May 4, 10:55 AM PDT | Areal Flood Advisory | MTR | 2 hr |
| May 4, 12:25 PM PDT | Areal Flood Advisory | MTR | 2 hr |
| Jun 2, 3:08 AM PDT | Heat Advisory | MTR | 5 days |
| Jun 9, 2:19 PM PDT | Heat Advisory | MTR | 54 hr |
| Jun 20, 12:49 AM PDT | Heat Advisory | MTR | 69 hr |
| Jun 28, 12:26 PM PDT | Excessive Heat Watch | MTR | 37 hr |
| Jun 30, 1:19 AM PDT | Excessive Heat Warning | MTR | 13 days |
| Jun 30, 1:19 AM PDT | Heat Advisory | MTR | 9 days |
| Jun 30, 8:28 PM PDT | Red Flag Warning | MTR | 6 days |
| Jul 1, 2:02 PM PDT | Coastal Flood Advisory | MTR | 4 days |
| Jul 8, 1:00 AM PDT | Heat Advisory | MTR | 6 days |
| Jul 17, 12:19 PM PDT | Heat Advisory | MTR | 59 hr |
| Jul 19, 1:48 AM PDT | Coastal Flood Advisory | MTR | 4 days |
| Jul 20, 2:00 PM PDT | Excessive Heat Warning | MTR | 3 days |
| Jul 20, 2:00 PM PDT | Heat Advisory | MTR | 5 days |
| Sep 3, 12:15 AM PDT | Heat Advisory | MTR | 4 days |
| Sep 22, 12:08 PM PDT | Heat Advisory | MTR | 56 hr |
| Sep 29, 2:02 AM PDT | Heat Advisory | MTR | 9 days |
| Sep 30, 12:38 PM PDT | Excessive Heat Warning | MTR | 6 days |
| Oct 4, 10:28 AM PDT | Red Flag Warning | MTR | 23 hr |
| Oct 7, 11:09 PM PDT | Heat Advisory | MTR | 8 hr |
| Oct 8, 7:17 AM PDT | Heat Advisory | MTR | 12 hr |
| Oct 14, 9:47 AM PDT | Fire Weather Watch | MTR | 24 hr |
| Oct 15, 9:46 AM PDT | Red Flag Warning | MTR | 4 days |
| Oct 16, 12:52 AM PDT | Wind Advisory | MTR | 3 days |
| Nov 4, 1:30 AM PST | Red Flag Warning | MTR | 3 days |
| Nov 13, 1:04 AM PST | Coastal Flood Advisory | MTR | 6 days |
| Nov 17, 11:32 PM PST | Frost Advisory | MTR | 32 hr |
| Nov 19, 12:16 AM PST | Wind Advisory | MTR | 54 hr |
| Nov 20, 11:17 PM PST | Areal Flood Advisory | MTR | 6 hr |
| Nov 21, 12:35 PM PST | Wind Advisory | MTR | 38 hr |
| Nov 22, 12:05 PM PST | Areal Flood Advisory | MTR | 9 hr |
| Nov 22, 2:58 PM PST | Flash Flood Warning | MTR | 3 hr |
| Nov 22, 4:49 PM PST | Flash Flood Warning | MTR | 3 hr |
| Nov 23, 10:40 AM PST | Areal Flood Advisory | MTR | 106 min |
| Nov 26, 2:06 AM PST | Frost Advisory | MTR | 55 hr |
| Nov 26, 10:51 PM PST | Frost Advisory | MTR | 58 hr |
| Nov 28, 12:10 AM PST | Frost Advisory | MTR | 57 hr |
| Dec 5, 10:49 AM PST | Tsunami Warning | AAQ | 65 min |
| Dec 8, 11:53 PM PST | Frost Advisory | MTR | 33 hr |
| Dec 10, 9:54 AM PST | Frost Advisory | MTR | 23 hr |
| Dec 11, 9:27 AM PST | Coastal Flood Advisory | MTR | 5 days |
| Dec 13, 12:59 AM PST | High Wind Warning | MTR | 33 hr |
| Dec 13, 12:59 AM PST | Wind Advisory | MTR | 33 hr |
| Dec 14, 1:38 AM PST | Areal Flood Advisory | MTR | 3 hr |
| Dec 14, 5:04 AM PST | Areal Flood Advisory | MTR | 3 hr |
| Dec 14, 11:02 AM PST | Frost Advisory | MTR | 22 hr |
| Dec 16, 10:46 PM PST | Dense Fog Advisory | MTR | 12 hr |
| Dec 17, 10:01 PM PST | Dense Fog Advisory | MTR | 15 hr |
| Dec 18, 9:25 PM PST | Dense Fog Advisory | MTR | 12 hr |
| Dec 24, 2:32 AM PST | Areal Flood Advisory | MTR | 118 min |
| Dec 24, 10:49 AM PST | Areal Flood Advisory | MTR | 3 hr |
| Dec 26, 10:15 PM PST | Areal Flood Advisory | MTR | 8 hr |
| Dec 29, 2:02 AM PST | Frost Advisory | MTR | 31 hr |
| Dec 29, 4:33 AM PST | Wind Advisory | MTR | 10 hr |
| Dec 29, 8:22 AM PST | Areal Flood Advisory | MTR | 4 hr |
| Dec 29, 2:05 PM PST | Frost Advisory | MTR | 44 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Severe storms | |
| Special Weather Statement | 7 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 2 |
| Flood Watch | 3 |
| Areal Flood Advisory | 21 |
| Heat | |
| Excessive Heat Warning | 3 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 12 |
| Cold | |
| Frost Advisory | 15 |
| Wind and dust | |
| High Wind Warning | 3 |
| Wind Advisory | 11 |
| Fire | |
| Red Flag Warning | 4 |
| Fire Weather Watch | 1 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
| Coast and beach | |
| Tsunami Warning | 1 |
| Coastal Flood Advisory | 11 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe 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.