Alert archive / Colorado / Arapahoe County
Weather alerts in Arapahoe County, Colorado, 2008
117 weather alerts in 2008, 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 2008. Tap one for its archive.
- Alerts
- 117
- Warnings
- 54
- Watches
- 22
- Advisories
- 23
- Busiest month
- August28 alerts
- Busiest day
- June 3, 200811 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
2 of 4 tornado warnings covering Arapahoe County in 2008 had a tornado report inside them; 2 of 4 tornado reports fell inside a warning, on average 5 minutes after it went out.
Arapahoe County, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 4 | 2 | 50% | 4 | 50% | 5 min |
| Severe thunderstorm warnings | 22 | 8 | 64% | 4 | 100% | 14 min |
| Flash flood warnings | 1 | 1 | 0% | 2 | 100% | 40 min |
Each office's whole area, 2008
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 58 | 16 | 72% | 44 | 64% | 13 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 147 | 52 | 65% | 140 | 54% | 20 min |
| NWS Denver/Boulder, CO: flash flood warnings | 14 | 3 | 79% | 7 | 86% | 40 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 15, 3:55 PM MST | Snow and Blowing Snow Advisory | BOU | 13 hr |
| Feb 4, 4:56 AM MST | Snow and Blowing Snow Advisory | BOU | 30 hr |
| Feb 13, 3:43 PM MST | Blowing Snow Advisory | BOU | 53 min |
| Feb 13, 4:36 PM MST | Snow and Blowing Snow Advisory | BOU | 24 hr |
| Mar 1, 4:54 AM MST | Red Flag Warning | BOU | 13 hr |
| Mar 1, 3:56 PM MST | Snow and Blowing Snow Advisory | BOU | 28 hr |
| Mar 1, 9:51 PM MST | Winter Storm Warning | BOU | 22 hr |
| Mar 2, 11:52 AM MST | Blizzard Warning | BOU | 8 hr |
| Mar 15, 12:14 PM MDT | Winter Storm Watch | BOU | 26 hr |
| Mar 16, 1:47 PM MDT | Heavy Snow Warning | BOU | 19 hr |
| Mar 16, 1:47 PM MDT | Snow Advisory | BOU | 5 hr |
| Mar 16, 6:37 PM MDT | Winter Storm Warning | BOU | 14 hr |
| Mar 28, 4:10 PM MDT | Fire Weather Watch | BOU | 17 hr |
| Mar 29, 9:04 AM MDT | Red Flag Warning | BOU | 9 hr |
| Apr 8, 3:06 PM MDT | Winter Storm Watch | BOU | 22 hr |
| Apr 9, 12:40 PM MDT | Snow and Blowing Snow Advisory | BOU | 27 hr |
| Apr 9, 12:40 PM MDT | Winter Storm Warning | BOU | 33 hr |
| Apr 14, 4:05 AM MDT | Fire Weather Watch | BOU | 11 hr |
| Apr 14, 2:59 PM MDT | Red Flag Warning | BOU | 28 hr |
| Apr 15, 3:16 PM MDT | Winter Storm Watch | BOU | 13 hr |
| Apr 16, 4:00 AM MDT | Winter Storm Warning | BOU | 25 hr |
| Apr 19, 10:17 AM MDT | Red Flag Warning | BOU | 10 hr |
| Apr 19, 8:00 PM MDT | Red Flag Warning | BOU | 24 hr |
| Apr 21, 3:21 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Apr 22, 3:47 PM MDT | Red Flag Warning | BOU | 29 hr |
| Apr 28, 3:53 PM MDT | Fire Weather Watch | BOU | 12 hr |
| Apr 29, 4:01 AM MDT | Red Flag Warning | BOU | 16 hr |
| Apr 29, 8:23 PM MDT | Red Flag Warning | BOU | 24 hr |
| May 1, 3:50 PM MDT | High Wind Watch | BOU | 12 hr |
| May 2, 3:29 AM MDT | High Wind Warning | BOU | 15 hr |
| May 2, 8:36 PM MDT | Freeze Warning | BOU | 12 hr |
| May 10, 2:22 PM MDT | Freeze Warning | BOU | 18 hr |
| May 21, 5:33 PM MDT | Mesoscale Discussion | SPC | 57 min |
| May 21, 9:44 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| May 22, 11:06 AM MDT | Mesoscale Discussion | SPC | 24 min |
| May 22, 11:25 AM MDT | Tornado Watch | SPC | 9 hr |
| May 22, 12:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| May 22, 4:50 PM MDT | Mesoscale Discussion | SPC | 85 min |
| May 28, 3:53 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jun 2, 7:52 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 2, 8:29 PM MDT | Severe Thunderstorm Warning | BOU | 26 min |
| Jun 2, 11:39 PM MDT | Severe Thunderstorm Warning | BOU | 51 min |
| Jun 3, 12:14 AM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Jun 3, 12:44 AM MDT | Severe Thunderstorm Warning | BOU | 31 min |
| Jun 3, 1:11 AM MDT | Severe Thunderstorm Warning | BOU | 49 min |
| Jun 3, 1:28 AM MDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jun 3, 12:53 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jun 3, 1:17 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 3, 3:12 PM MDT | Mesoscale Discussion | SPC | 63 min |
| Jun 3, 5:15 PM MDT | Mesoscale Discussion | SPC | 60 min |
| Jun 4, 11:54 AM MDT | Mesoscale Discussion | SPC | 96 min |
| Jun 4, 12:42 PM MDT | Tornado Watch | SPC | 7 hr |
| Jun 4, 2:26 PM MDT | Mesoscale Discussion | SPC | 64 min |
| Jun 9, 3:51 PM MDT | Red Flag Warning | BOU | 28 hr |
| Jun 12, 12:19 PM MDT | Red Flag Warning | BOU | 9 hr |
| Jun 17, 5:31 PM MDT | Mesoscale Discussion | SPC | 89 min |
| Jun 18, 12:02 PM MDT | Mesoscale Discussion | SPC | 28 min |
| Jun 19, 6:22 PM MDT | Severe Thunderstorm Watch | SPC | 27 hr |
| Jun 19, 8:58 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jun 20, 6:08 PM MDT | Mesoscale Discussion | SPC | 67 min |
| Jun 20, 6:43 PM MDT | Tornado Warning | BOU | 38 min |
| Jun 20, 8:26 PM MDT | Severe Thunderstorm Warning | BOU | 49 min |
| Jun 22, 4:32 PM MDT | Severe Thunderstorm Warning | BOU | 44 min |
| Jun 22, 4:48 PM MDT | Severe Thunderstorm Warning | BOU | 29 min |
| Jun 25, 8:38 PM MDT | Severe Thunderstorm Warning | BOU | 37 min |
| Jul 3, 5:27 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jul 3, 6:00 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 6, 2:38 PM MDT | Severe Thunderstorm Warning | BOU | 37 min |
| Jul 6, 3:14 PM MDT | Areal Flood Advisory | BOU | 57 min |
| Jul 17, 2:16 PM MDT | Severe Thunderstorm Warning | BOU | 44 min |
| Jul 17, 3:01 PM MDT | Severe Thunderstorm Warning | BOU | 44 min |
| Jul 18, 6:33 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| Jul 20, 1:11 PM MDT | Red Flag Warning | BOU | 8 hr |
| Jul 31, 3:55 PM MDT | Heat Advisory | BOU | 29 hr |
| Aug 1, 4:01 AM MDT | Red Flag Warning | BOU | 17 hr |
| Aug 2, 10:43 AM MDT | Heat Advisory | BOU | 9 hr |
| Aug 2, 11:52 AM MDT | Severe Thunderstorm Warning | BOU | 23 min |
| Aug 5, 3:25 PM MDT | Severe Thunderstorm Warning | BOU | 35 min |
| Aug 6, 11:52 AM MDT | Flash Flood Watch | BOU | 12 hr |
| Aug 6, 5:03 PM MDT | Areal Flood Advisory | BOU | 87 min |
| Aug 6, 6:00 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Aug 6, 6:26 PM MDT | Areal Flood Advisory | BOU | 94 min |
| Aug 6, 7:20 PM MDT | Areal Flood Advisory | BOU | 85 min |
| Aug 6, 7:36 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Aug 7, 11:37 AM MDT | Flash Flood Watch | BOU | 8 hr |
| Aug 8, 7:30 PM MDT | Areal Flood Advisory | BOU | 90 min |
| Aug 8, 7:51 PM MDT | Flash Flood Warning | BOU | 94 min |
| Aug 8, 8:49 PM MDT | Areal Flood Advisory | BOU | 116 min |
| Aug 8, 10:23 PM MDT | Areal Flood Warning | BOU | 3 hr |
| Aug 8, 10:48 PM MDT | Areal Flood Advisory | BOU | 117 min |
| Aug 10, 4:10 AM MDT | Flash Flood Watch | BOU | 16 hr |
| Aug 14, 11:47 AM MDT | Mesoscale Discussion | SPC | 88 min |
| Aug 14, 3:36 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 14, 6:10 PM MDT | Mesoscale Discussion | SPC | 95 min |
| Aug 15, 2:32 PM MDT | Flood Watch | BOU | 32 hr |
| Aug 20, 4:40 PM MDT | Tornado Warning | BOU | 34 min |
| Aug 24, 5:22 PM MDT | Severe Thunderstorm Warning | BOU | 34 min |
| Aug 24, 5:42 PM MDT | Tornado Warning | BOU | 48 min |
| Aug 24, 6:12 PM MDT | Areal Flood Advisory | BOU | 104 min |
| Aug 24, 6:28 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| Aug 25, 1:54 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 25, 5:02 PM MDT | Tornado Warning | BOU | 43 min |
| Sep 4, 8:06 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Sep 7, 8:49 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 7, 10:44 PM MDT | Mesoscale Discussion | SPC | 91 min |
| Oct 6, 11:13 AM MDT | Frost Advisory | BOU | 22 hr |
| Oct 12, 8:07 PM MDT | Freeze Warning | BOU | 13 hr |
| Oct 13, 2:47 PM MDT | Freeze Warning | BOU | 18 hr |
| Oct 20, 3:10 PM MDT | High Wind Watch | BOU | 13 hr |
| Oct 21, 2:11 PM MDT | High Wind Warning | BOU | 28 hr |
| Oct 22, 4:02 AM MDT | Freeze Warning | BOU | 29 hr |
| Nov 20, 2:46 AM MST | Winter Weather Advisory | BOU | 11 hr |
| Nov 30, 11:03 AM MST | Winter Weather Advisory | BOU | 9 hr |
| Dec 7, 9:31 AM MST | Winter Storm Watch | BOU | 20 hr |
| Dec 8, 5:49 AM MST | Winter Weather Advisory | BOU | 23 hr |
| Dec 8, 10:23 PM MST | Winter Storm Warning | BOU | 7 hr |
| Dec 14, 12:34 AM MST | Winter Weather Advisory | BOU | 15 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 archive20072009
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.