Alert archive / California / Los Angeles County

Weather alerts in Los Angeles County, California, 2012

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

Los Angeles County and its neighbors

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

Alerts: 102
Warnings: 24
Watches: 9
Advisories: 56
Busiest month: October16 alerts
Busiest day: October 11, 201210 alerts

Over time

By month

Warning verification

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

Los Angeles County, 2012

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	0			0
Severe thunderstorm warnings	3	0	100%	0
Flash flood warnings	5	3	40%	8	63%	24 min

Each office's whole area, 2012

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Los Angeles, CA: severe thunderstorm warnings	4	0	100%	1	0%
NWS Los Angeles, CA: flash flood warnings	7	3	57%	8	63%	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.

Issued	Product	Office	Lasted
Jan 2, 4:59 AM PST	High Surf Advisory	LOX	52 hr
Jan 4, 2:36 PM PST	High Surf Advisory	LOX	3 days
Jan 6, 1:46 PM PST	Fire Weather Watch	LOX	21 hr
Jan 6, 2:46 PM PST	High Wind Watch	LOX	12 hr
Jan 6, 2:46 PM PST	Wind Advisory	LOX	55 hr
Jan 7, 3:14 AM PST	High Wind Warning	LOX	36 hr
Jan 7, 10:01 AM PST	Red Flag Warning	LOX	32 hr
Jan 12, 9:44 AM PST	Red Flag Warning	LOX	32 hr
Jan 12, 9:43 PM PST	Wind Advisory	LOX	17 hr
Jan 20, 2:01 PM PST	High Surf Advisory	LOX	4 days
Jan 22, 3:36 AM PST	High Surf Warning	LOX	55 min
Jan 26, 2:31 PM PST	Wind Advisory	LOX	66 hr
Jan 26, 3:22 PM PST	Red Flag Warning	LOX	66 hr
Jan 27, 3:01 AM PST	High Wind Warning	LOX	36 hr
Feb 2, 3:41 AM PST	Wind Advisory	LOX	35 hr
Feb 12, 3:17 PM PST	Wind Advisory	LOX	33 hr
Feb 13, 1:48 AM PST	High Surf Advisory	LOX	42 hr
Feb 14, 3:07 PM PST	Wind Advisory	LOX	62 hr
Feb 15, 2:50 PM PST	Wind Advisory	LOX	39 hr
Feb 21, 1:58 PM PST	Wind Advisory	LOX	19 hr
Feb 23, 3:18 AM PST	Wind Advisory	LOX	23 hr
Feb 25, 8:46 PM PST	Wind Advisory	LOX	13 hr
Feb 26, 2:46 PM PST	Wind Advisory	LOX	36 hr
Feb 26, 4:55 PM PST	Coastal Flood Statement	LOX	40 hr
Feb 27, 8:33 PM PST	Frost Advisory	LOX	12 hr
Feb 27, 10:12 PM PST	High Surf Advisory	LOX	11 hr
Feb 29, 1:58 PM PST	Wind Advisory	LOX	70 hr
Mar 5, 1:53 PM PST	Wind Advisory	LOX	37 hr
Mar 5, 2:17 PM PST	High Surf Advisory	LOX	35 hr
Mar 16, 2:37 PM PDT	High Surf Advisory	LOX	68 hr
Mar 16, 8:01 PM PDT	Wind Advisory	LOX	56 hr
Mar 17, 8:16 AM PDT	Areal Flood Advisory	LOX	4 hr
Mar 25, 10:12 AM PDT	Areal Flood Advisory	LOX	3 hr
Mar 25, 1:02 PM PDT	Areal Flood Advisory	LOX	3 hr
Mar 25, 3:09 PM PDT	Areal Flood Advisory	LOX	3 hr
Mar 29, 4:01 AM PDT	Coastal Flood Statement	LOX	65 hr
Mar 30, 2:51 PM PDT	Wind Advisory	LOX	71 hr
Mar 31, 4:57 AM PDT	High Surf Advisory	LOX	58 hr
Apr 3, 2:51 PM PDT	Wind Advisory	LOX	69 hr
Apr 12, 3:12 PM PDT	Wind Advisory	LOX	23 hr
Apr 13, 11:04 AM PDT	Areal Flood Advisory	LOX	4 hr
May 21, 2:10 PM PDT	High Wind Warning	LOX	67 hr
May 21, 2:10 PM PDT	Wind Advisory	LOX	61 hr
May 24, 1:45 PM PDT	Coastal Flood Statement	LOX	55 hr
May 24, 2:51 PM PDT	Wind Advisory	LOX	51 hr
Jun 3, 10:09 PM PDT	Wind Advisory	LOX	59 hr
Jun 9, 3:34 AM PDT	Wind Advisory	LOX	30 hr
Jul 10, 5:51 PM PDT	Excessive Heat Warning	LOX	31 hr
Aug 7, 3:03 AM PDT	Excessive Heat Watch	LOX	23 hr
Aug 8, 2:21 PM PDT	Excessive Heat Watch	LOX	13 hr
Aug 9, 2:57 AM PDT	Excessive Heat Warning	LOX	41 hr
Aug 9, 2:47 PM PDT	Areal Flood Advisory	LOX	71 min
Aug 12, 9:47 PM PDT	Excessive Heat Warning	LOX	22 hr
Aug 13, 12:39 PM PDT	Areal Flood Advisory	LOX	111 min
Aug 13, 4:30 PM PDT	Areal Flood Advisory	LOX	3 hr
Aug 21, 10:27 AM PDT	Red Flag Warning	LOX	29 hr
Aug 29, 2:52 AM PDT	Coastal Flood Statement	LOX	6 days
Aug 29, 7:28 PM PDT	High Surf Advisory	LOX	64 hr
Aug 30, 2:58 PM PDT	Special Weather Statement	LOX	47 min
Aug 30, 4:01 PM PDT	Flash Flood Warning	LOX	2 hr
Aug 30, 4:14 PM PDT	Special Weather Statement	LOX	46 min
Aug 30, 5:07 PM PDT	Areal Flood Advisory	LOX	3 hr
Sep 9, 4:46 PM PDT	Severe Thunderstorm Warning	LOX	39 min
Sep 9, 5:22 PM PDT	Flash Flood Warning	LOX	3 hr
Sep 10, 3:40 PM PDT	Flash Flood Warning	LOX	3 hr
Sep 10, 3:49 PM PDT	Severe Thunderstorm Warning	LOX	26 min
Sep 10, 4:11 PM PDT	Severe Thunderstorm Warning	LOX	64 min
Sep 28, 1:14 PM PDT	Fire Weather Watch	LOX	3 days
Sep 29, 3:51 PM PDT	Red Flag Warning	LOX	3 days
Oct 11, 4:09 AM PDT	Special Weather Statement	LOX	51 min
Oct 11, 6:31 AM PDT	Special Weather Statement	LOX	44 min
Oct 11, 6:32 AM PDT	Special Weather Statement	LOX	43 min
Oct 11, 12:39 PM PDT	Areal Flood Advisory	LOX	111 min
Oct 11, 1:35 PM PDT	Areal Flood Advisory	LOX	115 min
Oct 11, 2:47 PM PDT	Special Weather Statement	LOX	28 min
Oct 11, 2:55 PM PDT	Flash Flood Warning	LOX	98 min
Oct 11, 3:29 PM PDT	Special Weather Statement	LOX	31 min
Oct 11, 3:35 PM PDT	Areal Flood Advisory	LOX	115 min
Oct 11, 4:37 PM PDT	Flash Flood Warning	LOX	113 min
Oct 11, 5:39 PM PDT	Areal Flood Advisory	LOX	88 min
Oct 23, 2:43 PM PDT	High Wind Watch	LOX	24 hr
Oct 23, 2:53 PM PDT	Fire Weather Watch	LOX	25 hr
Oct 24, 2:25 AM PDT	Wind Advisory	LOX	4 days
Oct 24, 3:08 PM PDT	High Wind Warning	LOX	47 hr
Oct 24, 3:42 PM PDT	Red Flag Warning	LOX	3 days
Nov 3, 9:53 AM PDT	Fire Weather Watch	LOX	25 hr
Nov 12, 3:40 AM PST	Wind Advisory	LOX	12 hr
Nov 12, 10:08 AM PST	Red Flag Warning	LOX	32 hr
Nov 23, 2:05 PM PST	Dense Fog Advisory	LOX	20 hr
Nov 24, 3:30 PM PST	Dense Fog Advisory	LOX	19 hr
Nov 25, 8:38 PM PST	Dense Fog Advisory	LOX	6 hr
Nov 27, 4:38 AM PST	Coastal Flood Statement	LOX	22 hr
Nov 28, 2:12 AM PST	High Surf Advisory	LOX	5 days
Dec 7, 10:05 AM PST	Fire Weather Watch	LOX	48 hr
Dec 8, 2:46 AM PST	Dense Fog Advisory	LOX	7 hr
Dec 8, 1:55 PM PST	Wind Advisory	LOX	36 hr
Dec 8, 3:23 PM PST	Red Flag Warning	LOX	41 hr
Dec 17, 2:00 PM PST	Wind Advisory	LOX	48 hr
Dec 19, 9:29 AM PST	Frost Advisory	LOX	24 hr
Dec 28, 6:36 PM PST	Coastal Flood Statement	LOX	45 hr
Dec 29, 8:12 PM PST	Frost Advisory	LOX	13 hr
Dec 30, 7:30 AM PST	Frost Advisory	LOX	26 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
Severe Thunderstorm Warning	3
Special Weather Statement	7
Flooding
Flash Flood Warning	5
Areal Flood Advisory	13
Heat
Excessive Heat Warning	3
Excessive Heat Watch	2
Cold
Frost Advisory	4
Wind and dust
High Wind Warning	4
High Wind Watch	2
Wind Advisory	25
Fire
Red Flag Warning	8
Fire Weather Watch	5
Fog and smoke
Dense Fog Advisory	4
Coast and beach
High Surf Warning	1
High Surf Advisory	10
Coastal Flood Statement	6

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2011 2013

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.