Alert archive / Colorado / Arapahoe County
Weather alerts in Arapahoe County, Colorado, 2016
140 weather alerts in 2016, 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 2016. Tap one for its archive.
- Alerts
- 140
- Warnings
- 52
- Watches
- 19
- Advisories
- 24
- Busiest month
- July32 alerts
- Busiest day
- May 7, 20167 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 2 tornado warnings covering Arapahoe County in 2016 had a tornado report inside them.
Arapahoe County, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 2 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 28 | 13 | 54% | 9 | 100% | 17 min |
| Flash flood warnings | 1 | 1 | 0% | 0 |
Each office's whole area, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 30 | 6 | 80% | 20 | 60% | 12 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 259 | 94 | 64% | 230 | 72% | 19 min |
| NWS Denver/Boulder, CO: flash flood warnings | 8 | 1 | 88% | 3 | 33% | 18 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 |
|---|---|---|---|
| Jan 7, 3:49 AM MST | Winter Weather Advisory | BOU | 34 hr |
| Jan 9, 8:13 PM MST | Dense Fog Advisory | BOU | 14 hr |
| Jan 30, 3:14 PM MST | Winter Storm Watch | BOU | 20 hr |
| Jan 31, 11:43 AM MST | Winter Storm Warning | BOU | 52 hr |
| Feb 13, 4:17 AM MST | Dense Fog Advisory | BOU | 5 hr |
| Feb 17, 9:24 AM MST | Fire Weather Watch | BOU | 20 hr |
| Feb 18, 5:24 AM MST | Red Flag Warning | BOU | 13 hr |
| Feb 24, 9:46 AM MST | Red Flag Warning | BOU | 7 hr |
| Mar 1, 3:44 AM MST | Fire Weather Watch | BOU | 11 hr |
| Mar 1, 2:41 PM MST | Red Flag Warning | BOU | 28 hr |
| Mar 14, 2:32 AM MDT | Red Flag Warning | BOU | 16 hr |
| Mar 17, 3:55 AM MDT | Winter Weather Advisory | BOU | 31 hr |
| Mar 17, 10:57 AM MDT | Winter Storm Warning | BOU | 31 hr |
| Mar 21, 3:27 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Mar 22, 3:34 PM MDT | Blizzard Warning | BOU | 29 hr |
| Mar 23, 4:33 AM MDT | Mesoscale Discussion | SPC | 5 hr |
| Mar 23, 11:08 AM MDT | Mesoscale Discussion | SPC | 6 hr |
| Mar 24, 4:15 AM MDT | Winter Weather Advisory | BOU | 56 hr |
| Mar 24, 3:25 PM MDT | Winter Storm Watch | BOU | 20 hr |
| Apr 5, 12:27 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 13, 3:28 PM MDT | Red Flag Warning | BOU | 28 hr |
| Apr 14, 6:04 AM MDT | Winter Storm Warning | BOU | 3 days |
| Apr 14, 1:06 PM MDT | Winter Storm Watch | BOU | 16 hr |
| Apr 14, 1:06 PM MDT | Winter Weather Advisory | BOU | 65 hr |
| Apr 15, 5:21 AM MDT | Winter Storm Watch | BOU | 11 hr |
| Apr 25, 8:26 PM MDT | Severe Thunderstorm Warning | BOU | 25 min |
| Apr 28, 4:26 AM MDT | Winter Storm Watch | BOU | 8 hr |
| Apr 28, 12:43 PM MDT | Winter Weather Advisory | BOU | 32 hr |
| May 7, 11:29 AM MDT | Mesoscale Discussion | SPC | 91 min |
| May 7, 12:31 PM MDT | Tornado Watch | SPC | 8 hr |
| May 7, 1:14 PM MDT | Severe Thunderstorm Warning | BOU | 31 min |
| May 7, 1:29 PM MDT | Tornado Warning | BOU | 16 min |
| May 7, 1:43 PM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| May 7, 2:08 PM MDT | Severe Thunderstorm Warning | BOU | 52 min |
| May 7, 2:35 PM MDT | Severe Thunderstorm Warning | BOU | 40 min |
| May 10, 1:24 PM MDT | Special Weather Statement | BOU | 36 min |
| May 10, 1:33 PM MDT | Special Weather Statement | BOU | 42 min |
| May 10, 2:03 PM MDT | Special Weather Statement | BOU | 27 min |
| May 10, 2:18 PM MDT | Mesoscale Discussion | SPC | 117 min |
| May 16, 3:32 AM MDT | Dense Fog Advisory | BOU | 6 hr |
| May 24, 11:31 AM MDT | Mesoscale Discussion | SPC | 59 min |
| May 24, 12:45 PM MDT | Tornado Watch | SPC | 7 hr |
| May 24, 2:05 PM MDT | Severe Thunderstorm Warning | BOU | 25 min |
| May 24, 2:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| May 26, 1:26 PM MDT | Severe Thunderstorm Warning | BOU | 49 min |
| May 26, 2:14 PM MDT | Severe Thunderstorm Warning | BOU | 14 min |
| May 26, 2:23 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 30, 1:56 PM MDT | Mesoscale Discussion | SPC | 64 min |
| May 31, 4:01 PM MDT | Special Weather Statement | BOU | 29 min |
| May 31, 6:09 PM MDT | Special Weather Statement | BOU | 36 min |
| Jun 6, 4:21 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jun 6, 4:48 PM MDT | Areal Flood Advisory | BOU | 117 min |
| Jun 6, 4:58 PM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| Jun 6, 5:44 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Jun 6, 5:44 PM MDT | Severe Thunderstorm Warning | BOU | 31 min |
| Jun 7, 1:37 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 7, 6:11 PM MDT | Severe Thunderstorm Warning | BOU | 34 min |
| Jun 13, 11:18 AM MDT | Mesoscale Discussion | SPC | 117 min |
| Jun 13, 12:11 PM MDT | Special Weather Statement | BOU | 34 min |
| Jun 13, 1:27 PM MDT | Tornado Watch | SPC | 8 hr |
| Jun 13, 4:16 PM MDT | Mesoscale Discussion | SPC | 89 min |
| Jun 13, 4:48 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| Jun 13, 5:06 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jun 13, 6:53 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jun 20, 2:38 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 23, 4:43 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 23, 4:45 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jun 28, 6:24 PM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| Jun 28, 7:07 PM MDT | Areal Flood Advisory | BOU | 53 min |
| Jun 28, 7:23 PM MDT | Special Weather Statement | BOU | 52 min |
| Jun 29, 5:30 PM MDT | Severe Thunderstorm Warning | BOU | 15 min |
| Jun 29, 5:55 PM MDT | Special Weather Statement | BOU | 35 min |
| Jun 30, 2:13 PM MDT | Flash Flood Watch | BOU | 10 hr |
| Jun 30, 4:03 PM MDT | Areal Flood Advisory | BOU | 117 min |
| Jul 1, 9:57 AM MDT | Flash Flood Watch | BOU | 11 hr |
| Jul 1, 2:25 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 2, 6:31 PM MDT | Special Weather Statement | BOU | 44 min |
| Jul 2, 6:33 PM MDT | Tornado Warning | BOU | 13 min |
| Jul 3, 5:11 PM MDT | Special Weather Statement | BOU | 34 min |
| Jul 8, 2:57 AM MDT | Special Weather Statement | BOU | 63 min |
| Jul 8, 4:31 PM MDT | Mesoscale Discussion | SPC | 59 min |
| Jul 9, 8:31 PM MDT | Red Flag Warning | BOU | 23 hr |
| Jul 15, 5:04 PM MDT | Severe Thunderstorm Warning | BOU | 26 min |
| Jul 15, 5:30 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 17, 2:03 PM MDT | Mesoscale Discussion | SPC | 57 min |
| Jul 17, 4:33 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| Jul 18, 6:44 PM MDT | Special Weather Statement | BOU | 46 min |
| Jul 19, 6:50 PM MDT | Severe Thunderstorm Warning | BOU | 13 min |
| Jul 19, 6:56 PM MDT | Areal Flood Advisory | BOU | 94 min |
| Jul 19, 7:09 PM MDT | Flash Flood Warning | BOU | 96 min |
| Jul 22, 3:48 PM MDT | Special Weather Statement | BOU | 42 min |
| Jul 23, 6:58 PM MDT | Special Weather Statement | BOU | 62 min |
| Jul 24, 1:50 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jul 24, 3:34 PM MDT | Severe Thunderstorm Warning | BOU | 41 min |
| Jul 24, 4:25 PM MDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 24, 4:28 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jul 25, 3:55 PM MDT | Special Weather Statement | BOU | 35 min |
| Jul 25, 4:45 PM MDT | Special Weather Statement | BOU | 60 min |
| Jul 25, 5:37 PM MDT | Special Weather Statement | BOU | 53 min |
| Jul 27, 7:21 PM MDT | Severe Thunderstorm Warning | BOU | 23 min |
| Jul 28, 1:58 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 28, 9:30 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 29, 12:34 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Jul 29, 1:08 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 29, 5:27 PM MDT | Mesoscale Discussion | SPC | 108 min |
| Jul 29, 8:28 PM MDT | Mesoscale Discussion | SPC | 92 min |
| Aug 2, 9:22 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Aug 7, 5:47 AM MDT | Dense Fog Advisory | BOU | 4 hr |
| Aug 11, 7:37 PM MDT | Special Weather Statement | BOU | 38 min |
| Aug 16, 4:56 PM MDT | Mesoscale Discussion | SPC | 64 min |
| Aug 19, 4:06 PM MDT | Severe Thunderstorm Warning | BOU | 24 min |
| Aug 19, 4:29 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Aug 19, 5:01 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Aug 19, 5:13 PM MDT | Severe Thunderstorm Warning | BOU | 62 min |
| Aug 19, 5:56 PM MDT | Areal Flood Advisory | BOU | 64 min |
| Aug 30, 7:30 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Aug 30, 9:34 PM MDT | Areal Flood Advisory | BOU | 116 min |
| Sep 2, 2:33 PM MDT | Mesoscale Discussion | SPC | 57 min |
| Sep 5, 3:52 AM MDT | Red Flag Warning | BOU | 15 hr |
| Sep 14, 12:26 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 22, 3:46 PM MDT | Red Flag Warning | BOU | 28 hr |
| Sep 25, 3:45 PM MDT | Frost Advisory | BOU | 16 hr |
| Oct 2, 3:15 AM MDT | Fire Weather Watch | BOU | 13 hr |
| Oct 2, 3:47 PM MDT | Red Flag Warning | BOU | 27 hr |
| Oct 4, 2:56 PM MDT | Freeze Warning | BOU | 18 hr |
| Oct 6, 4:05 AM MDT | Freeze Warning | BOU | 29 hr |
| Oct 14, 3:09 PM MDT | Fire Weather Watch | BOU | 23 hr |
| Oct 15, 2:14 PM MDT | Fire Weather Watch | BOU | 25 hr |
| Oct 15, 2:14 PM MDT | Red Flag Warning | BOU | 29 hr |
| Oct 16, 2:51 PM MDT | Red Flag Warning | BOU | 28 hr |
| Oct 19, 6:00 AM MDT | Freeze Watch | BOU | 8 hr |
| Oct 19, 2:04 PM MDT | Freeze Warning | BOU | 18 hr |
| Oct 30, 3:36 AM MDT | Dense Fog Advisory | BOU | 6 hr |
| Nov 16, 1:48 AM MST | Red Flag Warning | BOU | 16 hr |
| Nov 20, 2:07 PM MST | Winter Weather Advisory | BOU | 48 hr |
| Dec 5, 2:48 PM MST | Winter Weather Advisory | BOU | 44 hr |
| Dec 15, 10:21 AM MST | Winter Storm Warning | BOU | 47 hr |
| Dec 16, 12:58 PM MST | Wind Chill Advisory | BOU | 23 hr |
| Dec 16, 5:57 PM MST | Wind Chill Warning | BOU | 18 hr |
| Dec 16, 9:04 PM MST | Winter Weather Advisory | BOU | 11 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 archive20152017
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.