Alert archive / California / Stanislaus County
Weather alerts in Stanislaus County, California, 2009
10 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Stanislaus County and its neighbors
Each county as a circle sized by its count in 2009. Tap one for its archive.
- Alerts
- 10
- Warnings
- 2
- Watches
- 0
- Advisories
- 4
- Busiest month
- March4 alerts
- Busiest day
- March 2, 20092 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Stanislaus County, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 2 | 0 | 100% | 0 | ||
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2009
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sacramento, CA: tornado warnings | 0 | 1 | 0% | |||
| NWS Sacramento, CA: severe thunderstorm warnings | 31 | 0 | 100% | 3 | 0% | |
| NWS Sacramento, CA: flash flood warnings | 3 | 1 | 67% | 2 | 50% | 46 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 |
|---|---|---|---|
| Feb 23, 4:55 PM PST | Areal Flood Advisory | STO | 5 hr |
| Mar 2, 12:22 PM PST | Areal Flood Advisory | STO | 6 hr |
| Mar 2, 3:05 PM PST | Severe Thunderstorm Warning | STO | 55 min |
| Mar 2, 4:00 PM PST | Severe Thunderstorm Warning | STO | 30 min |
| Mar 3, 8:08 AM PST | Mesoscale Discussion | SPC | 67 min |
| Oct 13, 8:45 AM PDT | Areal Flood Advisory | STO | 12 hr |
| Oct 13, 8:42 PM PDT | Areal Flood Advisory | STO | 3 hr |
| Nov 27, 3:30 PM PST | Special Weather Statement | STO | 60 min |
| Nov 27, 4:41 PM PST | Special Weather Statement | STO | 64 min |
| Nov 27, 4:53 PM PST | Special Weather Statement | STO | 37 min |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Severe storms | |
| Severe Thunderstorm Warning | 2 |
| Mesoscale Discussion | 1 |
| Special Weather Statement | 3 |
| Flooding | |
| Areal Flood Advisory | 4 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20082010
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.