Alert archive / California / Ventura County

Weather alerts in Ventura County, California, 2012

10 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Ventura County and its neighbors

Each county as a circle sized by its count in 2012. Tap one for its archive.

Alerts
10
Warnings
2
Watches
0
Advisories
7
Busiest month
March5 alerts
Busiest day
March 25, 20124 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

Ventura County, 2012

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Tornado warnings00
Severe thunderstorm warnings010%
Flash flood warnings20100%0

Each office's whole area, 2012

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Los Angeles, CA: severe thunderstorm warnings40100%10%
NWS Los Angeles, CA: flash flood warnings7357%863%24 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.

IssuedProductOfficeLasted
Mar 17, 6:08 AM PDTAreal Flood AdvisoryLOX4 hr
Mar 25, 7:24 AM PDTAreal Flood AdvisoryLOX3 hr
Mar 25, 10:12 AM PDTAreal Flood AdvisoryLOX3 hr
Mar 25, 12:48 PM PDTMesoscale DiscussionSPC87 min
Mar 25, 1:02 PM PDTAreal Flood AdvisoryLOX3 hr
Apr 11, 2:50 AM PDTAreal Flood AdvisoryLOX3 hr
Apr 13, 10:20 AM PDTAreal Flood AdvisoryLOX96 min
Apr 13, 11:04 AM PDTAreal Flood AdvisoryLOX4 hr
Sep 10, 2:38 PM PDTFlash Flood WarningLOX3 hr
Oct 11, 1:02 PM PDTFlash Flood WarningLOX3 hr

By product

Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordForecastThe radar archive20112013

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.