Alert archive / Colorado / Jefferson County
Weather alerts in Jefferson County, Colorado, 2025
142 weather alerts in 2025, 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 2025. Tap one for its archive.
- Alerts
- 142
- Warnings
- 43
- Watches
- 25
- Advisories
- 39
- Busiest month
- December20 alerts
- Busiest day
- August 23, 20256 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, 2025
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 13 | 5 | 62% | 8 | 63% | 16 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2025
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 32 | 10 | 69% | 25 | 56% | 13 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 363 | 126 | 65% | 369 | 75% | 20 min |
| NWS Denver/Boulder, CO: flash flood warnings | 22 | 2 | 91% | 5 | 60% | 42 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 3, 1:36 PM MST | Dense Fog Advisory | BOU | 20 hr |
| Jan 3, 1:49 PM MST | Winter Weather Advisory | BOU | 49 hr |
| Jan 6, 1:50 AM MST | Winter Weather Advisory | BOU | 34 hr |
| Jan 9, 2:07 PM MST | Winter Weather Advisory | BOU | 57 hr |
| Jan 16, 1:51 PM MST | Winter Weather Advisory | BOU | 51 hr |
| Jan 17, 2:02 PM MST | Cold Weather Advisory | BOU | 4 days |
| Jan 19, 3:28 AM MST | Extreme Cold Watch | BOU | 23 hr |
| Jan 20, 2:46 AM MST | Extreme Cold Warning | BOU | 30 hr |
| Jan 21, 5:01 PM MST | High Wind Warning | BOU | 6 hr |
| Jan 23, 1:53 PM MST | Winter Weather Advisory | BOU | 63 hr |
| Feb 1, 7:57 PM MST | High Wind Watch | BOU | 8 hr |
| Feb 2, 4:02 AM MST | High Wind Warning | BOU | 25 hr |
| Feb 6, 2:42 PM MST | Winter Weather Advisory | BOU | 40 hr |
| Feb 10, 2:11 PM MST | Winter Weather Advisory | BOU | 43 hr |
| Feb 12, 2:21 AM MST | Cold Weather Advisory | BOU | 30 hr |
| Feb 12, 2:22 PM MST | Winter Storm Watch | BOU | 13 hr |
| Feb 13, 2:55 AM MST | Winter Weather Advisory | BOU | 65 hr |
| Feb 15, 2:00 AM MST | Dense Fog Advisory | BOU | 9 hr |
| Feb 15, 2:13 PM MST | Winter Storm Watch | BOU | 12 hr |
| Feb 16, 2:22 AM MST | Winter Storm Warning | BOU | 51 hr |
| Feb 16, 2:22 AM MST | Winter Weather Advisory | BOU | 51 hr |
| Feb 20, 3:12 AM MST | Winter Weather Advisory | BOU | 29 hr |
| Feb 20, 10:02 PM MST | Winter Storm Warning | BOU | 10 hr |
| Mar 2, 2:34 AM MST | Winter Storm Watch | BOU | 33 hr |
| Mar 2, 2:38 PM MST | Winter Weather Advisory | BOU | 50 hr |
| Mar 3, 2:16 AM MST | Winter Storm Warning | BOU | 25 hr |
| Mar 5, 1:48 PM MST | Winter Weather Advisory | BOU | 54 hr |
| Mar 13, 2:02 PM MDT | Winter Weather Advisory | BOU | 24 hr |
| Mar 16, 2:48 AM MDT | Fire Weather Watch | BOU | 11 hr |
| Mar 16, 1:54 PM MDT | Red Flag Warning | BOU | 29 hr |
| Mar 17, 12:38 PM MDT | Winter Weather Advisory | BOU | 44 hr |
| Mar 17, 7:00 PM MDT | Red Flag Warning | BOU | 24 hr |
| Mar 20, 2:29 PM MDT | Winter Weather Advisory | BOU | 58 hr |
| Mar 21, 2:28 AM MDT | Fire Weather Watch | BOU | 13 hr |
| Mar 21, 3:09 PM MDT | Red Flag Warning | BOU | 29 hr |
| Mar 31, 3:44 AM MDT | Winter Weather Advisory | BOU | 50 hr |
| Apr 8, 2:01 PM MDT | Red Flag Warning | BOU | 29 hr |
| Apr 10, 2:31 AM MDT | Fire Weather Watch | BOU | 36 hr |
| Apr 11, 2:45 PM MDT | Red Flag Warning | BOU | 29 hr |
| Apr 15, 2:50 PM MDT | Fire Weather Watch | BOU | 36 hr |
| Apr 16, 2:13 PM MDT | Red Flag Warning | BOU | 29 hr |
| Apr 16, 2:33 PM MDT | Winter Storm Watch | BOU | 12 hr |
| Apr 16, 2:33 PM MDT | Winter Weather Advisory | BOU | 63 hr |
| Apr 24, 2:45 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 4, 2:26 PM MDT | Winter Storm Watch | BOU | 24 hr |
| May 5, 2:14 PM MDT | Winter Storm Warning | BOU | 43 hr |
| May 5, 2:14 PM MDT | Winter Weather Advisory | BOU | 43 hr |
| May 14, 3:56 PM MDT | Mesoscale Discussion | SPC | 94 min |
| May 17, 2:33 PM MDT | Winter Weather Advisory | BOU | 37 hr |
| May 18, 3:03 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| May 24, 12:24 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 24, 5:09 PM MDT | Severe Thunderstorm Warning | BOU | 51 min |
| May 24, 5:46 PM MDT | Mesoscale Discussion | SPC | 89 min |
| May 24, 6:57 PM MDT | Severe Thunderstorm Warning | BOU | 48 min |
| May 24, 7:13 PM MDT | Dense Fog Advisory | BOU | 10 hr |
| May 27, 1:43 AM MDT | Dense Fog Advisory | BOU | 7 hr |
| May 27, 4:37 PM MDT | Mesoscale Discussion | SPC | 53 min |
| May 31, 4:05 PM MDT | Special Weather Statement | BOU | 25 min |
| Jun 1, 12:53 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 1, 3:59 PM MDT | Special Weather Statement | BOU | 31 min |
| Jun 1, 4:38 PM MDT | Severe Thunderstorm Warning | BOU | 37 min |
| Jun 5, 1:56 PM MDT | Special Weather Statement | BOU | 49 min |
| Jun 5, 5:49 PM MDT | Areal Flood Advisory | BOU | 56 min |
| Jun 8, 2:50 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jun 8, 6:23 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Jun 12, 8:02 PM MDT | Special Weather Statement | BOU | 28 min |
| Jun 13, 12:41 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 17, 10:48 AM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 17, 11:35 AM MDT | Severe Thunderstorm Warning | BOU | 40 min |
| Jun 17, 12:55 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 17, 1:58 PM MDT | Special Weather Statement | BOU | 47 min |
| Jun 18, 1:51 PM MDT | Heat Advisory | BOU | 3 days |
| Jun 25, 7:59 PM MDT | Areal Flood Advisory | BOU | 99 min |
| Jun 30, 3:54 PM MDT | Severe Thunderstorm Warning | BOU | 36 min |
| Jun 30, 4:25 PM MDT | Severe Thunderstorm Warning | BOU | 50 min |
| Jul 5, 1:04 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Jul 6, 6:12 PM MDT | Special Weather Statement | BOU | 48 min |
| Jul 7, 1:23 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 7, 2:28 PM MDT | Heat Advisory | BOU | 55 hr |
| Jul 10, 1:32 PM MDT | Special Weather Statement | BOU | 28 min |
| Jul 10, 1:51 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jul 11, 2:36 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jul 16, 1:36 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Jul 16, 2:45 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 16, 2:47 PM MDT | Severe Thunderstorm Warning | BOU | 28 min |
| Jul 16, 10:02 PM MDT | Flash Flood Warning | BOU | 118 min |
| Jul 16, 11:29 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Jul 20, 6:44 PM MDT | Special Weather Statement | BOU | 46 min |
| Jul 23, 2:43 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 24, 1:41 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 30, 12:10 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 30, 1:04 PM MDT | Special Weather Statement | BOU | 26 min |
| Jul 31, 1:49 PM MDT | Mesoscale Discussion | SPC | 56 min |
| Jul 31, 2:24 PM MDT | Special Weather Statement | BOU | 36 min |
| Aug 2, 3:21 PM MDT | Special Weather Statement | BOU | 39 min |
| Aug 5, 1:45 PM MDT | Heat Advisory | BOU | 53 hr |
| Aug 6, 2:47 PM MDT | Fire Weather Watch | BOU | 18 hr |
| Aug 7, 9:07 AM MDT | Red Flag Warning | BOU | 35 hr |
| Aug 10, 12:14 PM MDT | Special Weather Statement | BOU | 46 min |
| Aug 12, 2:33 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Aug 13, 2:50 PM MDT | Red Flag Warning | BOU | 29 hr |
| Aug 22, 1:49 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Aug 22, 5:57 PM MDT | Special Weather Statement | BOU | 33 min |
| Aug 23, 1:21 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Aug 23, 3:29 PM MDT | Special Weather Statement | BOU | 46 min |
| Aug 23, 3:49 PM MDT | Severe Thunderstorm Warning | BOU | 26 min |
| Aug 23, 4:13 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Aug 23, 4:23 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Aug 23, 4:54 PM MDT | Severe Thunderstorm Warning | BOU | 36 min |
| Aug 28, 6:27 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Sep 22, 2:13 PM MDT | Winter Weather Advisory | BOU | 28 hr |
| Oct 15, 2:02 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Oct 17, 1:34 PM MDT | Frost Advisory | BOU | 42 hr |
| Oct 17, 1:39 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Oct 18, 1:26 PM MDT | Fire Weather Watch | BOU | 24 hr |
| Oct 19, 1:32 PM MDT | Red Flag Warning | BOU | 28 hr |
| Oct 20, 2:06 AM MDT | Freeze Warning | BOU | 30 hr |
| Oct 27, 12:27 PM MDT | Freeze Warning | BOU | 22 hr |
| Oct 27, 12:27 PM MDT | Freeze Warning | BOU | 46 hr |
| Nov 6, 7:21 AM MST | Red Flag Warning | BOU | 10 hr |
| Nov 28, 2:29 AM MST | Winter Weather Advisory | BOU | 32 hr |
| Nov 29, 2:03 PM MST | Winter Weather Advisory | BOU | 39 hr |
| Dec 1, 1:52 PM MST | Winter Weather Advisory | BOU | 54 hr |
| Dec 4, 2:20 AM MST | Winter Storm Watch | BOU | 12 hr |
| Dec 4, 2:21 PM MST | Winter Storm Warning | BOU | 57 hr |
| Dec 7, 12:57 PM MST | High Wind Watch | BOU | 20 hr |
| Dec 8, 9:12 AM MST | High Wind Watch | BOU | 18 hr |
| Dec 8, 9:12 AM MST | High Wind Warning | BOU | 39 hr |
| Dec 10, 3:39 AM MST | High Wind Warning | BOU | 31 hr |
| Dec 11, 8:16 AM MST | Red Flag Warning | BOU | 9 hr |
| Dec 15, 12:55 PM MST | High Wind Watch | BOU | 13 hr |
| Dec 15, 1:20 PM MST | Fire Weather Watch | BOU | 14 hr |
| Dec 16, 1:51 AM MST | High Wind Warning | BOU | 58 hr |
| Dec 16, 3:06 AM MST | Red Flag Warning | BOU | 39 hr |
| Dec 17, 2:26 PM MST | High Wind Watch | BOU | 51 hr |
| Dec 17, 3:24 PM MST | Fire Weather Watch | BOU | 35 hr |
| Dec 18, 2:44 PM MST | Red Flag Warning | BOU | 33 hr |
| Dec 18, 6:01 PM MST | High Wind Warning | BOU | 26 hr |
| Dec 19, 2:07 AM MST | Winter Weather Advisory | BOU | 43 hr |
| Dec 21, 2:31 PM MST | Fire Weather Watch | BOU | 11 hr |
| Dec 22, 1:48 AM MST | Red Flag Warning | BOU | 15 hr |
| Dec 26, 2:40 PM MST | Winter Weather Advisory | BOU | 44 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 | 13 |
| Severe Thunderstorm Watch | 2 |
| Mesoscale Discussion | 21 |
| Special Weather Statement | 14 |
| Flooding | |
| Flash Flood Warning | 1 |
| Areal Flood Advisory | 4 |
| Winter | |
| Winter Storm Warning | 5 |
| Winter Storm Watch | 6 |
| Winter Weather Advisory | 25 |
| Heat | |
| Heat Advisory | 3 |
| Cold | |
| Extreme Cold Warning | 1 |
| Freeze Warning | 3 |
| Extreme Cold Watch | 1 |
| Cold Weather Advisory | 2 |
| Frost Advisory | 1 |
| Wind and dust | |
| High Wind Warning | 6 |
| High Wind Watch | 5 |
| Fire | |
| Red Flag Warning | 14 |
| Fire Weather Watch | 11 |
| 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 archive20242026
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.