Alert archive / Colorado / Jefferson County
Weather alerts in Jefferson County, Colorado, 2024
140 weather alerts in 2024, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Jefferson County and its neighbors
Each county as a circle sized by its count in 2024. Tap one for its archive.
- Alerts
- 140
- Warnings
- 43
- Watches
- 32
- Advisories
- 40
- Busiest month
- February23 alerts
- Busiest day
- January 16, 20244 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Jefferson County, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 6 | 4 | 33% | 5 | 40% | 6 min |
| Flash flood warnings | 3 | 0 | 100% | 1 | 0% |
Each office's whole area, 2024
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 27 | 2 | 93% | 15 | 20% | 11 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 295 | 119 | 60% | 339 | 79% | 20 min |
| NWS Denver/Boulder, CO: flash flood warnings | 32 | 9 | 72% | 14 | 79% | 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 7, 3:35 AM MST | Winter Weather Advisory | BOU | 31 hr |
| Jan 8, 1:41 PM MST | Winter Weather Advisory | BOU | 45 hr |
| Jan 10, 1:41 PM MST | Winter Weather Advisory | BOU | 22 hr |
| Jan 11, 3:10 AM MST | Wind Chill Watch | BOU | 23 hr |
| Jan 11, 3:10 AM MST | Winter Storm Watch | BOU | 9 hr |
| Jan 11, 11:59 AM MST | Winter Storm Warning | BOU | 4 days |
| Jan 12, 2:10 AM MST | Wind Chill Warning | BOU | 4 days |
| Jan 16, 3:53 AM MST | Winter Storm Warning | BOU | 61 hr |
| Jan 16, 3:53 AM MST | Winter Weather Advisory | BOU | 55 hr |
| Jan 16, 8:41 AM MST | Winter Weather Advisory | BOU | 8 hr |
| Jan 16, 2:05 PM MST | High Wind Warning | BOU | 17 hr |
| Feb 1, 2:13 AM MST | Winter Storm Watch | BOU | 12 hr |
| Feb 1, 2:09 PM MST | Winter Storm Warning | BOU | 54 hr |
| Feb 1, 2:09 PM MST | Winter Weather Advisory | BOU | 54 hr |
| Feb 2, 2:23 PM MST | Winter Storm Watch | BOU | 18 hr |
| Feb 3, 5:53 PM MST | Dense Fog Advisory | BOU | 16 hr |
| Feb 4, 5:15 PM MST | Dense Fog Advisory | BOU | 18 hr |
| Feb 7, 3:32 AM MST | Winter Weather Advisory | BOU | 35 hr |
| Feb 7, 3:33 AM MST | High Wind Watch | BOU | 10 hr |
| Feb 7, 1:34 PM MST | High Wind Warning | BOU | 13 hr |
| Feb 8, 2:30 PM MST | Winter Storm Watch | BOU | 22 hr |
| Feb 9, 12:47 PM MST | Winter Weather Advisory | BOU | 40 hr |
| Feb 14, 2:18 PM MST | Winter Weather Advisory | BOU | 63 hr |
| Feb 15, 2:22 AM MST | Dense Fog Advisory | BOU | 8 hr |
| Feb 24, 1:49 AM MST | Fire Weather Watch | BOU | 12 hr |
| Feb 24, 1:49 AM MST | Red Flag Warning | BOU | 16 hr |
| Feb 24, 12:31 PM MST | Winter Storm Watch | BOU | 24 hr |
| Feb 24, 1:43 PM MST | Red Flag Warning | BOU | 34 hr |
| Feb 25, 2:13 AM MST | Fire Weather Watch | BOU | 11 hr |
| Feb 25, 12:59 PM MST | Winter Storm Warning | BOU | 58 hr |
| Feb 25, 1:32 PM MST | Red Flag Warning | BOU | 28 hr |
| Feb 27, 8:39 AM MST | Snow Squall Warning | BOU | 36 min |
| Feb 27, 9:09 AM MST | Snow Squall Warning | BOU | 51 min |
| Feb 29, 12:10 PM MST | Fire Weather Watch | BOU | 19 hr |
| Mar 1, 5:42 AM MST | Winter Storm Watch | BOU | 9 hr |
| Mar 1, 6:46 AM MST | Red Flag Warning | BOU | 36 hr |
| Mar 1, 2:21 PM MST | Winter Storm Warning | BOU | 67 hr |
| Mar 6, 1:50 AM MST | Winter Storm Watch | BOU | 24 hr |
| Mar 7, 1:50 AM MST | Winter Weather Advisory | BOU | 39 hr |
| Mar 11, 2:29 PM MDT | Winter Storm Watch | BOU | 47 hr |
| Mar 12, 2:12 PM MDT | Winter Storm Warning | BOU | 64 hr |
| Mar 23, 3:22 AM MDT | Winter Weather Advisory | BOU | 57 hr |
| Mar 23, 3:06 PM MDT | Winter Storm Watch | BOU | 13 hr |
| Mar 24, 3:53 AM MDT | Winter Storm Warning | BOU | 26 hr |
| Apr 4, 2:58 PM MDT | High Wind Watch | BOU | 36 hr |
| Apr 5, 2:52 AM MDT | Winter Weather Advisory | BOU | 57 hr |
| Apr 5, 11:50 AM MDT | High Wind Warning | BOU | 54 hr |
| Apr 5, 1:37 PM MDT | Red Flag Warning | BOU | 53 hr |
| Apr 14, 2:26 PM MDT | Winter Storm Watch | BOU | 12 hr |
| Apr 15, 2:42 AM MDT | Winter Storm Warning | BOU | 36 hr |
| Apr 19, 3:22 AM MDT | Winter Weather Advisory | BOU | 30 hr |
| Apr 20, 2:00 PM MDT | Dense Fog Advisory | BOU | 19 hr |
| Apr 25, 1:51 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Apr 26, 1:36 PM MDT | Winter Storm Warning | BOU | 34 hr |
| Apr 26, 6:22 PM MDT | Severe Thunderstorm Warning | BOU | 38 min |
| Apr 26, 6:38 PM MDT | Severe Thunderstorm Warning | BOU | 34 min |
| May 5, 3:13 AM MDT | Winter Weather Advisory | BOU | 39 hr |
| May 5, 3:14 AM MDT | High Wind Watch | BOU | 11 hr |
| May 5, 1:59 PM MDT | High Wind Warning | BOU | 37 hr |
| May 6, 1:24 PM MDT | Freeze Watch | BOU | 23 hr |
| May 7, 3:09 AM MDT | Winter Weather Advisory | BOU | 21 hr |
| May 7, 4:07 PM MDT | Frost Advisory | BOU | 16 hr |
| May 9, 3:35 AM MDT | Winter Weather Advisory | BOU | 30 hr |
| May 12, 12:31 AM MDT | Winter Weather Advisory | BOU | 14 hr |
| May 13, 3:03 PM MDT | Special Weather Statement | BOU | 27 min |
| Jun 7, 2:23 PM MDT | Severe Thunderstorm Warning | BOU | 40 min |
| Jun 7, 9:08 PM MDT | Special Weather Statement | BOU | 37 min |
| Jun 8, 11:51 AM MDT | Mesoscale Discussion | SPC | 114 min |
| Jun 8, 12:26 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jun 9, 1:56 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 9, 7:00 PM MDT | Special Weather Statement | BOU | 30 min |
| Jun 14, 1:08 PM MDT | Special Weather Statement | BOU | 37 min |
| Jun 14, 1:34 PM MDT | Special Weather Statement | BOU | 26 min |
| Jun 14, 1:44 PM MDT | Mesoscale Discussion | SPC | 61 min |
| Jun 14, 1:52 PM MDT | Severe Thunderstorm Warning | BOU | 38 min |
| Jun 16, 2:42 PM MDT | Fire Weather Watch | BOU | 12 hr |
| Jun 16, 2:42 PM MDT | Red Flag Warning | BOU | 30 hr |
| Jun 20, 5:01 PM MDT | Special Weather Statement | BOU | 44 min |
| Jun 22, 2:15 PM MDT | Heat Advisory | BOU | 3 days |
| Jun 26, 2:53 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 27, 8:48 PM MDT | Special Weather Statement | BOU | 57 min |
| Jun 29, 6:18 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| Jul 7, 2:12 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 10, 12:24 PM MDT | Heat Advisory | BOU | 56 hr |
| Jul 10, 12:24 PM MDT | Heat Advisory | BOU | 3 days |
| Jul 10, 12:24 PM MDT | Heat Advisory | BOU | 4 days |
| Jul 13, 7:59 PM MDT | Fire Weather Watch | BOU | 8 hr |
| Jul 14, 4:25 AM MDT | Red Flag Warning | BOU | 17 hr |
| Jul 15, 2:49 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Jul 17, 12:20 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jul 17, 1:37 PM MDT | Special Weather Statement | BOU | 23 min |
| Jul 17, 1:59 PM MDT | Special Weather Statement | BOU | 31 min |
| Jul 18, 4:01 PM MDT | Mesoscale Discussion | SPC | 89 min |
| Jul 20, 8:19 PM MDT | Mesoscale Discussion | SPC | 56 min |
| Jul 20, 8:32 PM MDT | Severe Thunderstorm Warning | BOU | 28 min |
| Jul 29, 2:41 AM MDT | Heat Advisory | BOU | 41 hr |
| Aug 2, 1:42 PM MDT | Heat Advisory | BOU | 54 hr |
| Aug 4, 12:46 PM MDT | Special Weather Statement | BOU | 29 min |
| Aug 4, 1:29 PM MDT | Special Weather Statement | BOU | 46 min |
| Aug 5, 5:35 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Aug 8, 5:07 PM MDT | Flash Flood Warning | BOU | 2 hr |
| Aug 10, 4:34 PM MDT | Flash Flood Warning | BOU | 3 hr |
| Aug 12, 9:50 AM MDT | Flood Watch | BOU | 14 hr |
| Aug 13, 10:29 AM MDT | Flood Watch | BOU | 10 hr |
| Aug 13, 6:15 PM MDT | Flash Flood Warning | BOU | 58 min |
| Sep 4, 3:21 PM MDT | Special Weather Statement | BOU | 39 min |
| Sep 5, 12:32 AM MDT | Areal Flood Advisory | BOU | 118 min |
| Sep 10, 2:01 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Sep 11, 2:14 PM MDT | Red Flag Warning | BOU | 30 hr |
| Sep 17, 10:33 AM MDT | Mesoscale Discussion | SPC | 117 min |
| Sep 17, 1:50 PM MDT | Special Weather Statement | BOU | 25 min |
| Sep 17, 2:11 PM MDT | Special Weather Statement | BOU | 34 min |
| Sep 20, 2:51 PM MDT | Winter Weather Advisory | BOU | 42 hr |
| Oct 3, 2:18 PM MDT | Fire Weather Watch | BOU | 23 hr |
| Oct 4, 1:27 PM MDT | Red Flag Warning | BOU | 30 hr |
| Oct 21, 2:05 AM MDT | Winter Weather Advisory | BOU | 10 hr |
| Oct 24, 3:04 AM MDT | Red Flag Warning | BOU | 15 hr |
| Oct 28, 3:04 PM MDT | Freeze Watch | BOU | 23 hr |
| Oct 29, 1:59 PM MDT | Freeze Warning | BOU | 43 hr |
| Nov 2, 2:34 PM MDT | Winter Weather Advisory | BOU | 43 hr |
| Nov 3, 2:06 PM MST | Winter Storm Warning | BOU | 19 hr |
| Nov 4, 2:48 PM MST | Winter Storm Watch | BOU | 13 hr |
| Nov 5, 3:38 AM MST | Winter Weather Advisory | BOU | 61 hr |
| Nov 7, 3:51 AM MST | Winter Storm Watch | BOU | 10 hr |
| Nov 7, 1:43 PM MST | Winter Storm Warning | BOU | 46 hr |
| Nov 7, 1:43 PM MST | Winter Weather Advisory | BOU | 46 hr |
| Nov 8, 12:51 PM MST | Mesoscale Discussion | SPC | 4 hr |
| Nov 24, 1:38 PM MST | Winter Storm Watch | BOU | 12 hr |
| Nov 25, 1:15 AM MST | Winter Storm Warning | BOU | 61 hr |
| Nov 25, 1:15 AM MST | Winter Weather Advisory | BOU | 61 hr |
| Dec 9, 10:10 AM MST | Winter Weather Advisory | BOU | 13 hr |
| Dec 15, 2:52 AM MST | High Wind Warning | BOU | 23 hr |
| Dec 18, 9:53 AM MST | High Wind Warning | BOU | 20 hr |
| Dec 26, 2:05 PM MST | Winter Weather Advisory | BOU | 40 hr |
| Dec 27, 2:29 PM MST | Winter Weather Advisory | BOU | 45 hr |
| Dec 28, 1:52 PM MST | Winter Weather Advisory | BOU | 51 hr |
| Dec 28, 2:12 PM MST | High Wind Watch | BOU | 24 hr |
| Dec 28, 2:27 PM MST | Fire Weather Watch | BOU | 13 hr |
| Dec 29, 3:35 AM MST | Red Flag Warning | BOU | 37 hr |
| Dec 29, 2:17 PM MST | High Wind Warning | BOU | 27 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 | 6 |
| Severe Thunderstorm Watch | 1 |
| Mesoscale Discussion | 11 |
| Special Weather Statement | 14 |
| Flooding | |
| Flash Flood Warning | 3 |
| Flood Watch | 2 |
| Areal Flood Advisory | 2 |
| Winter | |
| Snow Squall Warning | 2 |
| Winter Storm Warning | 12 |
| Winter Storm Watch | 14 |
| Winter Weather Advisory | 27 |
| Heat | |
| Heat Advisory | 6 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Freeze Watch | 2 |
| Wind Chill Watch | 1 |
| Frost Advisory | 1 |
| Wind and dust | |
| High Wind Warning | 7 |
| High Wind Watch | 4 |
| Fire | |
| Red Flag Warning | 11 |
| Fire Weather Watch | 8 |
| Fog and smoke | |
| Dense Fog Advisory | 4 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20232025
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.