Alert archive / California / Yolo County

Weather alerts in Yolo County, California, 2009

7 weather alerts in 2009, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Yolo County and its neighbors

Each county as a circle sized by its count in 2009. Tap one for its archive.

Alerts
7
Warnings
0
Watches
0
Advisories
4
Busiest month
March3 alerts
Busiest day
March 3, 20093 alerts

Over time

By month

Warning verification

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

Yolo County, 2009

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

Each office's whole area, 2009

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Sacramento, CA: tornado warnings010%
NWS Sacramento, CA: severe thunderstorm warnings310100%30%
NWS Sacramento, CA: flash flood warnings3167%250%46 min
NWS San Diego, CA: severe thunderstorm warnings9189%250%46 min
NWS San Diego, CA: flash flood warnings7357%944%40 min
NWS San Francisco Bay Area, CA: severe thunderstorm warnings20100%10%
NWS San Francisco Bay Area, CA: flash flood warnings100100%10%
NWS Hanford, CA: tornado warnings010%
NWS Hanford, CA: severe thunderstorm warnings231152%2966%20 min
NWS Hanford, CA: flash flood warnings10100%20%
NWS Los Angeles, CA: severe thunderstorm warnings50100%10%
NWS Los Angeles, CA: flash flood warnings80100%10%
NWS Medford, OR: severe thunderstorm warnings211052%3043%11 min
NWS Medford, OR: flash flood warnings3167%617%0 min
NWS Reno, NV: severe thunderstorm warnings50394%1747%16 min
NWS Reno, NV: flash flood warnings100100%40%
NWS Las Vegas, NV: severe thunderstorm warnings53787%3926%17 min
NWS Las Vegas, NV: flash flood warnings32778%1937%55 min
NWS Phoenix, AZ: severe thunderstorm warnings541278%3757%17 min
NWS Phoenix, AZ: flash flood warnings16381%667%28 min
NWS Eureka, CA: severe thunderstorm warnings20195%333%11 min
NWS Eureka, CA: flash flood warnings10100%20%

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
Feb 17, 4:31 PM PSTAreal Flood AdvisorySTO6 hr
Mar 3, 8:08 AM PSTMesoscale DiscussionSPC67 min
Mar 3, 9:13 AM PSTAreal Flood AdvisorySTO6 hr
Mar 3, 3:12 PM PSTAreal Flood AdvisorySTO6 hr
Jun 3, 9:23 PM PDTSpecial Weather StatementSTO52 min
Jun 4, 12:58 AM PDTSpecial Weather StatementSTO62 min
Oct 13, 8:45 AM PDTAreal Flood AdvisorySTO12 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 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.