Alert archive / California / Contra Costa County
Weather alerts in Contra Costa County, California, 2016
30 weather alerts in 2016, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Contra Costa County and its neighbors
Each county as a circle sized by its count in 2016. Tap one for its archive.
- Alerts
- 30
- Warnings
- 3
- Watches
- 5
- Advisories
- 22
- Busiest month
- March10 alerts
- Busiest day
- March 6, 20164 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Contra Costa County, 2016
| 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 | 0 | 9 | 0% |
Each office's whole area, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Medford, OR: severe thunderstorm warnings | 19 | 2 | 89% | 4 | 50% | 23 min |
| NWS Medford, OR: flash flood warnings | 1 | 0 | 100% | 0 | ||
| NWS Los Angeles, CA: tornado warnings | 0 | 1 | 0% | |||
| NWS Los Angeles, CA: severe thunderstorm warnings | 7 | 4 | 43% | 52 | 35% | 34 min |
| NWS Los Angeles, CA: flash flood warnings | 24 | 7 | 71% | 29 | 38% | 62 min |
| NWS Eureka, CA: severe thunderstorm warnings | 5 | 0 | 100% | 0 | ||
| NWS Eureka, CA: flash flood warnings | 0 | 20 | 0% | |||
| NWS San Diego, CA: tornado warnings | 2 | 0 | 100% | 2 | 0% | |
| NWS San Diego, CA: severe thunderstorm warnings | 14 | 6 | 57% | 26 | 54% | 34 min |
| NWS San Diego, CA: flash flood warnings | 14 | 10 | 29% | 43 | 67% | 66 min |
| NWS Las Vegas, NV: tornado warnings | 0 | 1 | 0% | |||
| NWS Las Vegas, NV: severe thunderstorm warnings | 92 | 17 | 82% | 69 | 70% | 23 min |
| NWS Las Vegas, NV: flash flood warnings | 123 | 46 | 63% | 125 | 66% | 84 min |
| NWS Hanford, CA: severe thunderstorm warnings | 14 | 2 | 86% | 14 | 14% | 25 min |
| NWS Hanford, CA: flash flood warnings | 11 | 1 | 91% | 11 | 18% | 75 min |
| NWS Sacramento, CA: tornado warnings | 4 | 0 | 100% | 4 | 0% | |
| NWS Sacramento, CA: severe thunderstorm warnings | 13 | 4 | 69% | 11 | 55% | 17 min |
| NWS Sacramento, CA: flash flood warnings | 4 | 1 | 75% | 1 | 100% | 61 min |
| NWS Reno, NV: severe thunderstorm warnings | 2 | 0 | 100% | 2 | 0% | |
| NWS Reno, NV: flash flood warnings | 5 | 0 | 100% | 5 | 0% | |
| NWS San Francisco Bay Area, CA: tornado warnings | 0 | 2 | 0% | |||
| NWS San Francisco Bay Area, CA: severe thunderstorm warnings | 2 | 0 | 100% | 1 | 0% | |
| NWS San Francisco Bay Area, CA: flash flood warnings | 23 | 3 | 87% | 93 | 17% | 121 min |
| NWS Phoenix, AZ: tornado warnings | 1 | 0 | 100% | 0 | ||
| NWS Phoenix, AZ: severe thunderstorm warnings | 50 | 12 | 76% | 37 | 51% | 20 min |
| NWS Phoenix, AZ: flash flood warnings | 7 | 5 | 29% | 12 | 42% | 34 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 5, 1:57 PM PST | Coastal Flood Advisory | MTR | 20 hr |
| Jan 5, 2:04 PM PST | Flash Flood Watch | MTR | 28 hr |
| Jan 6, 1:49 PM PST | Coastal Flood Advisory | MTR | 20 hr |
| Jan 19, 4:23 AM PST | Areal Flood Advisory | MTR | 5 hr |
| Jan 21, 8:29 AM PST | Coastal Flood Advisory | MTR | 29 hr |
| Jan 22, 1:01 PM PST | Coastal Flood Advisory | MTR | 24 hr |
| Jan 31, 2:31 AM PST | Wind Advisory | MTR | 25 hr |
| Mar 4, 3:14 AM PST | Wind Advisory | MTR | 46 hr |
| Mar 5, 7:28 AM PST | Flash Flood Watch | MTR | 15 hr |
| Mar 5, 4:17 PM PST | Areal Flood Advisory | MTR | 6 hr |
| Mar 5, 10:14 PM PST | Flash Flood Watch | MTR | 5 hr |
| Mar 6, 4:57 AM PST | Wind Advisory | MTR | 23 hr |
| Mar 6, 5:16 AM PST | Flash Flood Watch | MTR | 23 hr |
| Mar 6, 9:21 PM PST | Areal Flood Advisory | MTR | 6 hr |
| Mar 9, 3:18 PM PST | Flash Flood Watch | MTR | 4 days |
| Mar 10, 4:56 PM PST | Areal Flood Advisory | MTR | 4 hr |
| Mar 11, 3:28 AM PST | Wind Advisory | MTR | 18 hr |
| Apr 24, 2:25 AM PDT | Wind Advisory | MTR | 22 hr |
| Sep 23, 10:21 AM PDT | Heat Advisory | MTR | 58 hr |
| Sep 23, 10:21 AM PDT | Heat Advisory | MTR | 3 days |
| Nov 18, 11:22 AM PST | Wind Advisory | MTR | 27 hr |
| Dec 15, 3:40 AM PST | Wind Advisory | MTR | 21 hr |
| Dec 15, 3:12 PM PST | Areal Flood Advisory | MTR | 4 hr |
| Dec 15, 5:46 PM PST | Areal Flood Advisory | MTR | 3 hr |
| Dec 16, 7:14 AM PST | Frost Advisory | MTR | 25 hr |
| Dec 16, 7:14 AM PST | Frost Advisory | MTR | 49 hr |
| Dec 16, 7:14 AM PST | Freeze Warning | MTR | 49 hr |
| Dec 18, 12:14 PM PST | Freeze Warning | MTR | 20 hr |
| Dec 18, 7:15 PM PST | Frost Advisory | MTR | 13 hr |
| Dec 26, 10:56 PM PST | Freeze Warning | MTR | 10 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Flooding | |
| Flash Flood Watch | 5 |
| Areal Flood Advisory | 6 |
| Heat | |
| Heat Advisory | 2 |
| Cold | |
| Freeze Warning | 3 |
| Frost Advisory | 3 |
| Wind and dust | |
| Wind Advisory | 7 |
| Coast and beach | |
| Coastal Flood Advisory | 4 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20152017
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.