Alert archive / Colorado / Jefferson County
Weather alerts in Jefferson County, Colorado, 2015
138 weather alerts in 2015, 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 2015. Tap one for its archive.
- Alerts
- 138
- Warnings
- 52
- Watches
- 23
- Advisories
- 46
- Busiest month
- June38 alerts
- Busiest day
- June 5, 20159 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 1 tornado warnings covering Jefferson County in 2015 had a tornado report inside them.
Jefferson County, 2015
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 16 | 9 | 44% | 12 | 50% | 6 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2015
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 59 | 12 | 80% | 29 | 52% | 13 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 193 | 70 | 64% | 208 | 67% | 15 min |
| NWS Denver/Boulder, CO: flash flood warnings | 33 | 5 | 85% | 9 | 100% | 37 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 4, 5:49 AM MST | High Wind Watch | BOU | 23 hr |
| Jan 5, 4:39 AM MST | High Wind Warning | BOU | 15 hr |
| Jan 7, 12:38 AM MST | Dense Fog Advisory | BOU | 8 hr |
| Jan 7, 3:25 AM MST | Winter Weather Advisory | BOU | 6 hr |
| Jan 8, 3:08 PM MST | Winter Weather Advisory | BOU | 17 hr |
| Jan 16, 7:05 PM MST | High Wind Warning | BOU | 5 hr |
| Jan 21, 2:28 AM MST | Winter Weather Advisory | BOU | 18 hr |
| Jan 31, 10:49 PM MST | Winter Weather Advisory | BOU | 8 hr |
| Feb 3, 5:14 AM MST | Winter Storm Warning | BOU | 13 hr |
| Feb 3, 6:11 PM MST | Winter Storm Warning | BOU | 27 hr |
| Feb 15, 3:56 AM MST | Winter Weather Advisory | BOU | 40 hr |
| Feb 15, 1:38 PM MST | Winter Storm Warning | BOU | 30 hr |
| Feb 17, 9:02 PM MST | Winter Weather Advisory | BOU | 18 hr |
| Feb 19, 2:26 PM MST | Winter Storm Watch | BOU | 22 hr |
| Feb 20, 4:25 AM MST | Winter Storm Warning | BOU | 67 hr |
| Feb 21, 12:38 PM MST | Mesoscale Discussion | SPC | 5 hr |
| Feb 24, 3:13 PM MST | Winter Storm Watch | BOU | 13 hr |
| Feb 25, 4:18 AM MST | Winter Storm Warning | BOU | 24 hr |
| Feb 25, 4:18 AM MST | Winter Weather Advisory | BOU | 24 hr |
| Mar 3, 4:27 AM MST | Winter Weather Advisory | BOU | 25 hr |
| Mar 17, 3:36 PM MDT | Winter Storm Watch | BOU | 14 hr |
| Mar 18, 6:00 AM MDT | Winter Storm Warning | BOU | 23 hr |
| Mar 18, 6:00 AM MDT | Winter Weather Advisory | BOU | 27 hr |
| Mar 23, 2:40 PM MDT | Red Flag Warning | BOU | 27 hr |
| Mar 28, 4:55 AM MDT | Red Flag Warning | BOU | 13 hr |
| Apr 7, 4:36 AM MDT | Red Flag Warning | BOU | 15 hr |
| Apr 11, 9:10 PM MDT | Red Flag Warning | BOU | 22 hr |
| Apr 15, 5:42 AM MDT | Winter Storm Watch | BOU | 8 hr |
| Apr 15, 1:40 PM MDT | Winter Storm Warning | BOU | 56 hr |
| Apr 25, 3:28 PM MDT | Winter Storm Watch | BOU | 14 hr |
| Apr 26, 5:18 AM MDT | Winter Storm Warning | BOU | 23 hr |
| May 1, 12:31 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 1, 3:12 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| May 5, 4:21 AM MDT | Flash Flood Watch | BOU | 13 hr |
| May 7, 2:39 PM MDT | Winter Storm Watch | BOU | 39 hr |
| May 8, 11:08 AM MDT | Areal Flood Advisory | BOU | 60 hr |
| May 8, 1:13 PM MDT | Special Weather Statement | BOU | 47 min |
| May 8, 2:16 PM MDT | Areal Flood Advisory | BOU | 89 min |
| May 9, 5:10 AM MDT | Flash Flood Watch | BOU | 15 hr |
| May 9, 5:15 AM MDT | Winter Storm Warning | BOU | 25 hr |
| May 9, 8:50 AM MDT | Areal Flood Warning | BOU | 12 hr |
| May 9, 9:09 AM MDT | Winter Storm Watch | BOU | 4 hr |
| May 10, 5:26 AM MDT | Frost Advisory | BOU | 26 hr |
| May 10, 5:56 AM MDT | Winter Storm Warning | BOU | 3 hr |
| May 16, 1:56 PM MDT | Special Weather Statement | BOU | 49 min |
| May 16, 2:04 PM MDT | Areal Flood Advisory | BOU | 116 min |
| May 17, 3:02 PM MDT | Winter Storm Watch | BOU | 20 hr |
| May 18, 10:34 AM MDT | Winter Storm Warning | BOU | 31 hr |
| May 18, 5:41 PM MDT | Flash Flood Watch | BOU | 10 hr |
| May 21, 4:40 AM MDT | Winter Weather Advisory | BOU | 25 hr |
| May 23, 12:54 PM MDT | Tornado Watch | SPC | 6 hr |
| May 23, 1:38 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Jun 3, 2:03 PM MDT | Tornado Watch | SPC | 7 hr |
| Jun 3, 4:23 PM MDT | Severe Thunderstorm Warning | BOU | 37 min |
| Jun 3, 4:59 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jun 3, 5:29 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Jun 3, 6:29 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Jun 3, 7:14 PM MDT | Mesoscale Discussion | SPC | 61 min |
| Jun 4, 2:20 PM MDT | Tornado Watch | SPC | 8 hr |
| Jun 4, 9:42 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jun 4, 9:47 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jun 4, 11:00 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jun 4, 11:16 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jun 5, 12:42 AM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jun 5, 12:48 AM MDT | Areal Flood Advisory | BOU | 117 min |
| Jun 5, 4:27 AM MDT | Flash Flood Watch | BOU | 18 hr |
| Jun 5, 12:49 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Jun 5, 1:09 PM MDT | Tornado Watch | SPC | 6 hr |
| Jun 5, 9:11 PM MDT | Areal Flood Advisory | BOU | 94 min |
| Jun 10, 11:17 AM MDT | River Flood Advisory | BOU | 52 hr |
| Jun 10, 11:41 AM MDT | Flash Flood Watch | BOU | 39 hr |
| Jun 11, 10:35 AM MDT | River Flood Warning | BOU | 55 hr |
| Jun 11, 4:58 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jun 11, 6:43 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Jun 11, 11:23 PM MDT | Areal Flood Warning | BOU | 6 hr |
| Jun 12, 5:16 AM MDT | Areal Flood Warning | BOU | 4 hr |
| Jun 14, 5:56 AM MDT | River Flood Warning | BOU | 24 hr |
| Jun 15, 8:24 PM MDT | River Flood Warning | BOU | 37 hr |
| Jun 17, 11:00 AM MDT | River Flood Warning | BOU | 4 days |
| Jun 17, 2:56 PM MDT | Areal Flood Warning | BOU | 72 hr |
| Jun 17, 5:54 PM MDT | Severe Thunderstorm Warning | BOU | 22 min |
| Jun 18, 8:53 PM MDT | Severe Thunderstorm Warning | BOU | 29 min |
| Jun 20, 3:55 AM MDT | Areal Flood Warning | BOU | 60 hr |
| Jun 22, 9:34 AM MDT | Areal Flood Advisory | BOU | 60 hr |
| Jun 24, 2:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Jun 24, 4:45 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Jun 25, 2:30 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 25, 4:25 PM MDT | Mesoscale Discussion | SPC | 95 min |
| Jun 25, 6:34 PM MDT | Severe Thunderstorm Warning | BOU | 41 min |
| Jun 25, 6:39 PM MDT | Areal Flood Advisory | BOU | 111 min |
| Jul 1, 2:43 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 1, 2:53 PM MDT | Special Weather Statement | BOU | 37 min |
| Jul 9, 8:13 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Jul 21, 12:46 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Jul 21, 1:45 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Aug 10, 1:01 PM MDT | Special Weather Statement | BOU | 59 min |
| Aug 10, 1:53 PM MDT | Special Weather Statement | BOU | 52 min |
| Aug 13, 5:24 PM MDT | Areal Flood Advisory | BOU | 2 hr |
| Aug 14, 4:02 PM MDT | Areal Flood Advisory | BOU | 3 hr |
| Aug 14, 4:36 PM MDT | Flash Flood Warning | BOU | 3 hr |
| Aug 16, 12:08 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 17, 2:32 PM MDT | Severe Thunderstorm Warning | BOU | 16 min |
| Aug 17, 2:32 PM MDT | Tornado Watch | SPC | 7 hr |
| Aug 17, 3:07 PM MDT | Severe Thunderstorm Warning | BOU | 38 min |
| Aug 17, 3:18 PM MDT | Tornado Warning | BOU | 27 min |
| Sep 29, 1:48 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Sep 29, 3:40 PM MDT | Special Weather Statement | BOU | 50 min |
| Sep 29, 4:43 PM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| Sep 29, 4:55 PM MDT | Severe Thunderstorm Warning | BOU | 35 min |
| Oct 2, 2:09 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 20, 5:40 AM MDT | Winter Weather Advisory | BOU | 30 hr |
| Oct 22, 10:07 AM MDT | Winter Weather Advisory | BOU | 5 hr |
| Oct 22, 6:19 PM MDT | Winter Weather Advisory | BOU | 10 hr |
| Oct 23, 3:54 AM MDT | Frost Advisory | BOU | 28 hr |
| Oct 27, 3:13 AM MDT | Frost Advisory | BOU | 29 hr |
| Nov 4, 3:35 AM MST | Winter Weather Advisory | BOU | 32 hr |
| Nov 10, 5:05 AM MST | Winter Storm Warning | BOU | 30 hr |
| Nov 10, 5:05 AM MST | Winter Weather Advisory | BOU | 30 hr |
| Nov 15, 3:36 PM MST | Winter Storm Watch | BOU | 14 hr |
| Nov 16, 5:57 AM MST | Winter Storm Warning | BOU | 26 hr |
| Nov 16, 5:57 AM MST | Winter Weather Advisory | BOU | 26 hr |
| Nov 18, 3:29 AM MST | High Wind Warning | BOU | 9 hr |
| Nov 19, 3:35 AM MST | Winter Weather Advisory | BOU | 41 hr |
| Nov 25, 10:25 AM MST | Winter Weather Advisory | BOU | 42 hr |
| Nov 30, 3:38 PM MST | Winter Weather Advisory | BOU | 20 hr |
| Dec 9, 5:45 AM MST | High Wind Warning | BOU | 21 hr |
| Dec 10, 2:56 PM MST | Winter Storm Watch | BOU | 17 hr |
| Dec 11, 8:14 AM MST | Winter Weather Advisory | BOU | 31 hr |
| Dec 14, 3:45 AM MST | Winter Weather Advisory | BOU | 37 hr |
| Dec 14, 3:12 PM MST | Winter Storm Warning | BOU | 26 hr |
| Dec 17, 4:01 PM MST | High Wind Warning | BOU | 19 hr |
| Dec 21, 4:49 AM MST | High Wind Watch | BOU | 10 hr |
| Dec 21, 5:00 AM MST | Winter Storm Warning | BOU | 64 hr |
| Dec 21, 5:00 AM MST | Winter Weather Advisory | BOU | 10 hr |
| Dec 21, 2:49 PM MST | High Wind Warning | BOU | 12 hr |
| Dec 23, 3:14 AM MST | Dense Fog Advisory | BOU | 7 hr |
| Dec 23, 9:04 PM MST | Winter Weather Advisory | BOU | 6 hr |
| Dec 24, 2:59 AM MST | Winter Weather Advisory | BOU | 49 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 | 16 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 1 |
| Tornado Watch | 5 |
| Mesoscale Discussion | 11 |
| Special Weather Statement | 6 |
| Flooding | |
| Areal Flood Warning | 5 |
| Flash Flood Warning | 1 |
| River Flood Warning | 4 |
| Flash Flood Watch | 5 |
| Areal Flood Advisory | 16 |
| River Flood Advisory | 1 |
| Winter | |
| Winter Storm Warning | 15 |
| Winter Storm Watch | 10 |
| Winter Weather Advisory | 24 |
| Cold | |
| Frost Advisory | 3 |
| Wind and dust | |
| High Wind Warning | 6 |
| High Wind Watch | 2 |
| Fire | |
| Red Flag Warning | 4 |
| Fog and smoke | |
| Dense Fog Advisory | 2 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20142016
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.