Alert archive / Colorado / Arapahoe County

Weather alerts in Arapahoe County, Colorado, 2013

159 weather alerts in 2013, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Arapahoe County and its neighbors

Each county as a circle sized by its count in 2013. Tap one for its archive.

Alerts: 159
Warnings: 64
Watches: 25
Advisories: 34
Busiest month: June45 alerts
Busiest day: September 12, 201312 alerts

Over time

By month

Warning verification

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

0 of 4 tornado warnings covering Arapahoe County in 2013 had a tornado report inside them.

Arapahoe County, 2013

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
Tornado warnings	4	0	100%	0
Severe thunderstorm warnings	25	7	72%	13	31%	19 min
Flash flood warnings	11	2	82%	4	100%	72 min

Each office's whole area, 2013

	Warnings	With a report	False alarm ratio	Reports	Inside a warning	Mean lead time
NWS Denver/Boulder, CO: tornado warnings	61	9	85%	16	75%	18 min
NWS Denver/Boulder, CO: severe thunderstorm warnings	227	65	71%	173	61%	18 min
NWS Denver/Boulder, CO: flash flood warnings	85	19	78%	50	82%	148 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, Mountain Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Lasted
Feb 8, 3:18 PM MST	Winter Weather Advisory	BOU	38 hr
Feb 17, 1:05 PM MST	Red Flag Warning	BOU	5 hr
Feb 19, 4:19 AM MST	Winter Storm Watch	BOU	30 hr
Feb 20, 4:17 AM MST	Winter Weather Advisory	BOU	30 hr
Feb 20, 10:14 AM MST	Winter Storm Warning	BOU	31 hr
Feb 22, 3:27 PM MST	Blizzard Watch	BOU	24 hr
Feb 22, 3:27 PM MST	Winter Storm Watch	BOU	24 hr
Feb 23, 3:41 PM MST	Blizzard Warning	BOU	31 hr
Feb 23, 3:41 PM MST	Winter Storm Warning	BOU	29 hr
Feb 24, 5:44 AM MST	Mesoscale Discussion	SPC	4 hr
Feb 26, 5:55 PM MST	Winter Weather Advisory	BOU	10 hr
Mar 7, 4:21 AM MST	Winter Storm Watch	BOU	24 hr
Mar 8, 4:14 AM MST	Winter Storm Warning	BOU	37 hr
Mar 8, 11:30 AM MST	Blizzard Warning	BOU	36 hr
Mar 9, 6:33 AM MST	Mesoscale Discussion	SPC	4 hr
Mar 21, 4:03 PM MDT	Winter Storm Watch	BOU	14 hr
Mar 22, 6:20 AM MDT	Winter Storm Warning	BOU	36 hr
Mar 22, 4:28 PM MDT	Winter Weather Advisory	BOU	26 hr
Apr 7, 4:15 AM MDT	Winter Storm Watch	BOU	36 hr
Apr 8, 11:19 AM MDT	Blizzard Warning	BOU	27 hr
Apr 8, 11:19 AM MDT	Winter Storm Warning	BOU	27 hr
Apr 8, 4:26 PM MDT	Winter Weather Advisory	BOU	35 hr
Apr 15, 4:51 AM MDT	Winter Storm Warning	BOU	23 hr
Apr 15, 4:51 AM MDT	Winter Weather Advisory	BOU	23 hr
Apr 16, 3:52 PM MDT	Blizzard Watch	BOU	16 hr
Apr 16, 3:52 PM MDT	Winter Weather Advisory	BOU	35 hr
Apr 17, 7:52 AM MDT	Blizzard Warning	BOU	11 hr
Apr 22, 5:46 AM MDT	Winter Weather Advisory	BOU	27 hr
Apr 30, 12:12 PM MDT	Winter Weather Advisory	BOU	39 hr
May 19, 6:14 PM MDT	Special Weather Statement	BOU	31 min
May 26, 2:49 PM MDT	Mesoscale Discussion	SPC	56 min
May 28, 7:36 PM MDT	Special Weather Statement	BOU	24 min
Jun 10, 3:26 PM MDT	Severe Thunderstorm Warning	BOU	34 min
Jun 10, 3:56 PM MDT	Severe Thunderstorm Warning	BOU	34 min
Jun 10, 7:50 PM MDT	Special Weather Statement	BOU	40 min
Jun 12, 1:52 PM MDT	Red Flag Warning	BOU	7 hr
Jun 12, 1:52 PM MDT	Red Flag Warning	BOU	31 hr
Jun 13, 1:14 PM MDT	Mesoscale Discussion	SPC	91 min
Jun 13, 3:29 PM MDT	Special Weather Statement	BOU	46 min
Jun 13, 4:04 PM MDT	Severe Thunderstorm Watch	SPC	4 hr
Jun 13, 5:00 PM MDT	Special Weather Statement	BOU	45 min
Jun 14, 1:38 PM MDT	Mesoscale Discussion	SPC	2 hr
Jun 15, 1:53 PM MDT	Mesoscale Discussion	SPC	97 min
Jun 15, 2:34 PM MDT	Severe Thunderstorm Watch	SPC	8 hr
Jun 15, 5:57 PM MDT	Mesoscale Discussion	SPC	63 min
Jun 15, 6:47 PM MDT	Severe Thunderstorm Warning	BOU	28 min
Jun 16, 1:28 PM MDT	Mesoscale Discussion	SPC	92 min
Jun 17, 2:21 PM MDT	Severe Thunderstorm Watch	SPC	9 hr
Jun 17, 5:09 PM MDT	Mesoscale Discussion	SPC	66 min
Jun 18, 1:07 PM MDT	Mesoscale Discussion	SPC	113 min
Jun 18, 1:53 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 18, 2:07 PM MDT	Tornado Warning	BOU	23 min
Jun 18, 3:18 PM MDT	Tornado Warning	BOU	27 min
Jun 18, 3:51 PM MDT	Severe Thunderstorm Warning	BOU	39 min
Jun 18, 5:09 PM MDT	Fire Weather Watch	BOU	21 hr
Jun 18, 5:11 PM MDT	Mesoscale Discussion	SPC	94 min
Jun 18, 7:52 PM MDT	Mesoscale Discussion	SPC	83 min
Jun 19, 2:12 PM MDT	Red Flag Warning	BOU	30 hr
Jun 20, 3:54 AM MDT	Fire Weather Watch	BOU	25 hr
Jun 21, 5:04 AM MDT	Red Flag Warning	BOU	15 hr
Jun 21, 3:35 PM MDT	Red Flag Warning	BOU	28 hr
Jun 22, 12:11 PM MDT	Mesoscale Discussion	SPC	2 hr
Jun 22, 4:18 PM MDT	Tornado Watch	SPC	7 hr
Jun 23, 3:05 PM MDT	Fire Weather Watch	BOU	14 hr
Jun 23, 3:48 PM MDT	Mesoscale Discussion	SPC	87 min
Jun 23, 4:40 PM MDT	Severe Thunderstorm Watch	SPC	7 hr
Jun 23, 5:22 PM MDT	Severe Thunderstorm Warning	BOU	23 min
Jun 23, 6:12 PM MDT	Severe Thunderstorm Warning	BOU	33 min
Jun 23, 6:44 PM MDT	Severe Thunderstorm Warning	BOU	31 min
Jun 23, 7:17 PM MDT	Severe Thunderstorm Warning	BOU	28 min
Jun 23, 7:19 PM MDT	Mesoscale Discussion	SPC	56 min
Jun 23, 7:46 PM MDT	Severe Thunderstorm Warning	BOU	29 min
Jun 24, 1:30 AM MDT	Severe Thunderstorm Warning	BOU	45 min
Jun 24, 5:01 AM MDT	Red Flag Warning	BOU	15 hr
Jun 28, 1:54 PM MDT	Mesoscale Discussion	SPC	3 hr
Jun 28, 7:30 PM MDT	Severe Thunderstorm Warning	BOU	45 min
Jun 29, 12:44 PM MDT	Mesoscale Discussion	SPC	3 hr
Jul 7, 4:12 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 10, 1:09 PM MDT	Mesoscale Discussion	SPC	66 min
Jul 10, 1:29 PM MDT	Severe Thunderstorm Watch	SPC	10 hr
Jul 10, 2:48 PM MDT	Special Weather Statement	BOU	42 min
Jul 12, 4:43 PM MDT	Severe Thunderstorm Warning	BOU	47 min
Jul 13, 5:20 PM MDT	Areal Flood Advisory	BOU	115 min
Jul 14, 7:51 PM MDT	Areal Flood Advisory	BOU	84 min
Jul 15, 12:31 PM MDT	Areal Flood Advisory	BOU	119 min
Jul 20, 4:03 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 20, 5:16 PM MDT	Severe Thunderstorm Warning	BOU	29 min
Jul 20, 5:28 PM MDT	Tornado Warning	BOU	32 min
Jul 20, 6:02 PM MDT	Severe Thunderstorm Warning	BOU	28 min
Jul 20, 6:07 PM MDT	Areal Flood Advisory	BOU	83 min
Jul 20, 6:09 PM MDT	Areal Flood Advisory	BOU	96 min
Jul 20, 7:23 PM MDT	Mesoscale Discussion	SPC	97 min
Jul 20, 7:53 PM MDT	Areal Flood Advisory	BOU	82 min
Jul 27, 2:05 PM MDT	Mesoscale Discussion	SPC	115 min
Jul 27, 4:19 PM MDT	Severe Thunderstorm Watch	SPC	6 hr
Jul 28, 4:20 PM MDT	Mesoscale Discussion	SPC	2 hr
Jul 31, 7:42 PM MDT	Severe Thunderstorm Warning	BOU	33 min
Jul 31, 8:07 PM MDT	Severe Thunderstorm Warning	BOU	23 min
Jul 31, 8:18 PM MDT	Tornado Warning	BOU	27 min
Jul 31, 8:42 PM MDT	Severe Thunderstorm Warning	BOU	33 min
Aug 3, 1:50 PM MDT	Mesoscale Discussion	SPC	85 min
Aug 3, 2:35 PM MDT	Tornado Watch	SPC	6 hr
Aug 3, 4:14 PM MDT	Severe Thunderstorm Warning	BOU	46 min
Aug 3, 5:21 PM MDT	Mesoscale Discussion	SPC	54 min
Aug 3, 7:31 PM MDT	Areal Flood Advisory	BOU	89 min
Aug 3, 7:54 PM MDT	Flash Flood Warning	BOU	3 hr
Aug 4, 7:25 PM MDT	Special Weather Statement	BOU	35 min
Aug 6, 4:19 PM MDT	Flash Flood Watch	BOU	27 hr
Aug 8, 7:13 PM MDT	Areal Flood Advisory	BOU	3 hr
Aug 8, 7:37 PM MDT	Flash Flood Warning	BOU	3 hr
Aug 10, 7:20 PM MDT	Severe Thunderstorm Warning	BOU	25 min
Aug 12, 2:33 PM MDT	Severe Thunderstorm Warning	BOU	42 min
Aug 12, 2:35 PM MDT	Mesoscale Discussion	SPC	2 hr
Aug 12, 2:58 PM MDT	Areal Flood Advisory	BOU	3 hr
Aug 12, 2:58 PM MDT	Severe Thunderstorm Warning	BOU	47 min
Aug 13, 2:05 PM MDT	Mesoscale Discussion	SPC	115 min
Aug 22, 5:45 PM MDT	Areal Flood Advisory	BOU	3 hr
Aug 22, 5:45 PM MDT	Severe Thunderstorm Warning	BOU	30 min
Sep 9, 4:09 PM MDT	Mesoscale Discussion	SPC	3 hr
Sep 9, 4:49 PM MDT	Special Weather Statement	BOU	41 min
Sep 10, 4:20 PM MDT	Areal Flood Advisory	BOU	85 min
Sep 10, 5:04 PM MDT	Areal Flood Advisory	BOU	56 min
Sep 11, 4:06 PM MDT	Areal Flood Advisory	BOU	114 min
Sep 11, 9:47 PM MDT	Areal Flood Advisory	BOU	3 hr
Sep 11, 10:01 PM MDT	Flash Flood Warning	BOU	3 hr
Sep 12, 12:59 AM MDT	Areal Flood Warning	BOU	3 hr
Sep 12, 5:00 AM MDT	Flash Flood Watch	BOU	40 hr
Sep 12, 7:24 AM MDT	Flash Flood Warning	BOU	3 hr
Sep 12, 7:32 AM MDT	Areal Flood Advisory	BOU	3 hr
Sep 12, 8:28 AM MDT	Areal Flood Warning	BOU	12 hr
Sep 12, 9:02 AM MDT	Flash Flood Warning	BOU	3 hr
Sep 12, 9:12 AM MDT	Flash Flood Warning	BOU	3 hr
Sep 12, 12:14 PM MDT	Flash Flood Warning	BOU	3 hr
Sep 12, 3:13 PM MDT	Areal Flood Advisory	BOU	3 hr
Sep 12, 5:04 PM MDT	Flash Flood Warning	BOU	4 hr
Sep 12, 7:35 PM MDT	Areal Flood Warning	BOU	12 hr
Sep 13, 7:34 AM MDT	Areal Flood Warning	BOU	24 hr
Sep 14, 4:30 AM MDT	Flash Flood Watch	BOU	40 hr
Sep 14, 3:23 PM MDT	Flash Flood Warning	BOU	3 hr
Sep 14, 3:38 PM MDT	Severe Thunderstorm Warning	BOU	37 min
Sep 14, 4:23 PM MDT	Flash Flood Warning	BOU	3 hr
Sep 15, 9:10 AM MDT	Areal Flood Warning	BOU	12 hr
Sep 15, 12:32 PM MDT	Flash Flood Warning	BOU	4 hr
Sep 15, 9:22 PM MDT	Areal Flood Advisory	BOU	12 hr
Sep 22, 5:42 PM MDT	Severe Thunderstorm Warning	BOU	33 min
Sep 22, 6:04 PM MDT	Severe Thunderstorm Warning	BOU	41 min
Sep 23, 4:16 AM MDT	Special Weather Statement	BOU	44 min
Sep 27, 4:13 AM MDT	Frost Advisory	BOU	28 hr
Oct 3, 10:27 AM MDT	Freeze Watch	BOU	20 hr
Oct 4, 6:06 AM MDT	Freeze Warning	BOU	27 hr
Oct 16, 3:42 PM MDT	Winter Weather Advisory	BOU	41 hr
Oct 21, 2:05 AM MDT	Dense Fog Advisory	BOU	7 hr
Oct 29, 8:13 AM MDT	Dense Fog Advisory	BOU	3 hr
Nov 20, 3:07 PM MST	Winter Weather Advisory	BOU	25 hr
Dec 2, 4:16 AM MST	Winter Storm Warning	BOU	59 hr
Dec 2, 3:42 PM MST	Winter Storm Watch	BOU	13 hr
Dec 3, 4:52 AM MST	Winter Weather Advisory	BOU	31 hr
Dec 4, 11:49 AM MST	Winter Weather Advisory	BOU	3 hr
Dec 21, 5:15 AM MST	Dense Fog Advisory	BOU	5 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	25
Tornado Warning	4
Severe Thunderstorm Watch	8
Tornado Watch	2
Mesoscale Discussion	27
Special Weather Statement	9
Flooding
Areal Flood Warning	5
Flash Flood Warning	11
Flash Flood Watch	3
Areal Flood Advisory	17
Winter
Blizzard Warning	4
Winter Storm Warning	7
Blizzard Watch	2
Winter Storm Watch	6
Winter Weather Advisory	13
Cold
Freeze Warning	1
Freeze Watch	1
Frost Advisory	1
Fire
Red Flag Warning	7
Fire Weather Watch	3
Fog and smoke
Dense Fog Advisory	3

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record Forecast The radar archive 2012 2014

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.