Alert archive / Colorado / Washington County
Weather alerts in Washington County, Colorado, 2020
148 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Washington County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 148
- Warnings
- 75
- Watches
- 20
- Advisories
- 9
- Busiest month
- July39 alerts
- Busiest day
- May 4, 20208 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 Washington County in 2020 had a tornado report inside them; 0 of 8 tornado reports fell inside a warning.
Washington County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 8 | 0% | |
| Severe thunderstorm warnings | 45 | 21 | 53% | 33 | 52% | 22 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Denver/Boulder, CO: tornado warnings | 5 | 2 | 60% | 25 | 16% | 13 min |
| NWS Denver/Boulder, CO: severe thunderstorm warnings | 220 | 86 | 61% | 308 | 72% | 26 min |
| NWS Denver/Boulder, CO: flash flood warnings | 5 | 1 | 80% | 1 | 100% | 29 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 6, 4:55 AM MST | High Wind Warning | BOU | 28 hr |
| Jan 16, 2:09 PM MST | High Wind Warning | BOU | 36 hr |
| Feb 2, 3:45 PM MST | Winter Weather Advisory | BOU | 42 hr |
| Feb 24, 3:42 AM MST | Winter Weather Advisory | BOU | 37 hr |
| Mar 4, 8:20 AM MST | Red Flag Warning | BOU | 9 hr |
| Mar 17, 1:15 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Mar 17, 8:25 PM MDT | Dense Fog Advisory | BOU | 13 hr |
| Mar 18, 1:02 PM MDT | Blizzard Warning | BOU | 35 hr |
| Mar 19, 4:45 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Mar 26, 2:48 PM MDT | Winter Weather Advisory | BOU | 45 hr |
| Mar 27, 2:23 PM MDT | Blizzard Warning | BOU | 22 hr |
| Apr 28, 3:27 AM MDT | Red Flag Warning | BOU | 17 hr |
| May 1, 5:19 PM MDT | Mesoscale Discussion | SPC | 116 min |
| May 1, 7:29 PM MDT | Special Weather Statement | BOU | 31 min |
| May 2, 8:09 PM MDT | Special Weather Statement | BOU | 51 min |
| May 2, 8:51 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| May 3, 2:44 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 3, 8:05 PM MDT | Severe Thunderstorm Warning | BOU | 25 min |
| May 3, 8:30 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| May 3, 8:59 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 3, 11:18 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| May 3, 11:48 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| May 4, 12:12 AM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| May 4, 12:28 AM MDT | Severe Thunderstorm Warning | BOU | 32 min |
| May 4, 12:39 AM MDT | Mesoscale Discussion | SPC | 3 hr |
| May 5, 2:31 PM MDT | Frost Advisory | BOU | 17 hr |
| May 7, 6:00 PM MDT | High Wind Warning | BOU | 2 hr |
| May 9, 3:03 AM MDT | Frost Advisory | BOU | 29 hr |
| May 11, 5:15 AM MDT | Frost Advisory | BOU | 2 hr |
| May 15, 2:15 PM MDT | Mesoscale Discussion | SPC | 90 min |
| May 15, 5:44 PM MDT | Special Weather Statement | BOU | 46 min |
| May 20, 1:02 AM MDT | Special Weather Statement | BOU | 43 min |
| Jun 3, 1:05 PM MDT | Mesoscale Discussion | SPC | 85 min |
| Jun 4, 2:39 PM MDT | Severe Thunderstorm Warning | BOU | 51 min |
| Jun 4, 3:29 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Jun 5, 12:50 PM MDT | High Wind Warning | BOU | 31 hr |
| Jun 5, 3:37 PM MDT | Red Flag Warning | BOU | 53 hr |
| Jun 6, 11:29 AM MDT | Mesoscale Discussion | SPC | 91 min |
| Jun 6, 12:21 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 6, 2:15 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Jun 6, 5:14 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 6, 5:18 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| Jun 6, 5:58 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jun 6, 5:58 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jun 6, 6:36 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jun 8, 3:28 AM MDT | High Wind Warning | BOU | 36 hr |
| Jun 8, 11:46 PM MDT | Severe Thunderstorm Warning | BOU | 29 min |
| Jun 9, 12:43 AM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jun 15, 3:54 PM MDT | Red Flag Warning | BOU | 28 hr |
| Jun 26, 12:07 PM MDT | Mesoscale Discussion | SPC | 113 min |
| Jun 26, 1:12 PM MDT | Severe Thunderstorm Watch | SPC | 10 hr |
| Jun 26, 3:51 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Jun 26, 6:27 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jun 26, 7:08 PM MDT | Severe Thunderstorm Warning | BOU | 37 min |
| Jun 28, 3:11 PM MDT | Red Flag Warning | BOU | 29 hr |
| Jul 2, 12:56 PM MDT | Special Weather Statement | BOU | 34 min |
| Jul 2, 1:42 PM MDT | Severe Thunderstorm Warning | BOU | 33 min |
| Jul 2, 1:51 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jul 2, 1:58 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 2, 2:36 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jul 2, 3:15 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 3, 5:22 PM MDT | Severe Thunderstorm Warning | BOU | 23 min |
| Jul 3, 5:48 PM MDT | Severe Thunderstorm Warning | BOU | 27 min |
| Jul 3, 6:13 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jul 3, 7:01 PM MDT | Severe Thunderstorm Warning | BOU | 44 min |
| Jul 6, 3:05 PM MDT | Red Flag Warning | BOU | 29 hr |
| Jul 7, 4:45 PM MDT | Special Weather Statement | BOU | 45 min |
| Jul 7, 5:33 PM MDT | Special Weather Statement | BOU | 42 min |
| Jul 7, 7:30 PM MDT | Special Weather Statement | BOU | 45 min |
| Jul 7, 7:45 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 7, 10:26 PM MDT | Special Weather Statement | BOU | 64 min |
| Jul 9, 2:37 PM MDT | Mesoscale Discussion | SPC | 83 min |
| Jul 9, 5:11 PM MDT | Special Weather Statement | BOU | 49 min |
| Jul 9, 5:25 PM MDT | Severe Thunderstorm Warning | BOU | 39 min |
| Jul 12, 2:07 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 12, 3:18 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| Jul 12, 3:56 PM MDT | Severe Thunderstorm Warning | BOU | 34 min |
| Jul 13, 2:08 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 13, 2:36 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 13, 4:29 PM MDT | Severe Thunderstorm Warning | BOU | 61 min |
| Jul 13, 5:59 PM MDT | Severe Thunderstorm Warning | BOU | 61 min |
| Jul 14, 12:53 PM MDT | Mesoscale Discussion | SPC | 97 min |
| Jul 16, 4:31 PM MDT | Special Weather Statement | BOU | 44 min |
| Jul 19, 12:36 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jul 19, 4:06 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 19, 5:31 PM MDT | Severe Thunderstorm Warning | BOU | 44 min |
| Jul 19, 5:47 PM MDT | Severe Thunderstorm Warning | BOU | 43 min |
| Jul 21, 1:12 PM MDT | Mesoscale Discussion | SPC | 93 min |
| Jul 21, 1:33 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 21, 7:15 PM MDT | Mesoscale Discussion | SPC | 90 min |
| Jul 21, 9:28 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Jul 21, 10:15 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Jul 24, 3:51 PM MDT | Severe Thunderstorm Warning | BOU | 24 min |
| Jul 28, 5:50 PM MDT | Special Weather Statement | BOU | 40 min |
| Aug 4, 12:52 PM MDT | Mesoscale Discussion | SPC | 113 min |
| Aug 4, 1:46 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 4, 4:16 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Aug 4, 4:50 PM MDT | Special Weather Statement | BOU | 55 min |
| Aug 4, 5:03 PM MDT | Severe Thunderstorm Warning | BOU | 42 min |
| Aug 4, 5:13 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Aug 4, 5:42 PM MDT | Severe Thunderstorm Warning | BOU | 48 min |
| Aug 5, 12:27 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 5, 1:26 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 5, 5:21 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Aug 5, 5:30 PM MDT | Severe Thunderstorm Warning | BOU | 45 min |
| Aug 5, 5:58 PM MDT | Severe Thunderstorm Warning | BOU | 47 min |
| Aug 6, 12:45 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 6, 5:13 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 1:17 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Aug 11, 2:11 PM MDT | Special Weather Statement | BOU | 34 min |
| Aug 15, 1:42 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 15, 5:15 PM MDT | Severe Thunderstorm Warning | BOU | 30 min |
| Aug 15, 5:39 PM MDT | Severe Thunderstorm Warning | BOU | 36 min |
| Aug 15, 5:47 PM MDT | Special Weather Statement | BOU | 13 min |
| Aug 15, 6:03 PM MDT | Tornado Warning | BOU | 27 min |
| Aug 16, 12:56 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 16, 1:45 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 16, 5:47 PM MDT | Mesoscale Discussion | SPC | 88 min |
| Aug 16, 6:25 PM MDT | Special Weather Statement | BOU | 50 min |
| Aug 19, 6:59 PM MDT | Severe Thunderstorm Warning | BOU | 46 min |
| Aug 29, 12:15 PM MDT | Mesoscale Discussion | SPC | 90 min |
| Aug 29, 3:21 PM MDT | Red Flag Warning | BOU | 29 hr |
| Sep 4, 2:40 PM MDT | Fire Weather Watch | BOU | 13 hr |
| Sep 4, 2:40 PM MDT | Red Flag Warning | BOU | 3 days |
| Sep 7, 3:41 AM MDT | Freeze Warning | BOU | 55 hr |
| Sep 25, 12:45 PM MDT | Red Flag Warning | BOU | 31 hr |
| Oct 4, 4:01 AM MDT | Red Flag Warning | BOU | 38 hr |
| Oct 9, 2:49 AM MDT | Fire Weather Watch | BOU | 13 hr |
| Oct 9, 3:43 PM MDT | Fire Weather Watch | BOU | 12 hr |
| Oct 9, 3:43 PM MDT | Red Flag Warning | BOU | 28 hr |
| Oct 10, 3:44 AM MDT | Red Flag Warning | BOU | 40 hr |
| Oct 11, 3:45 AM MDT | Fire Weather Watch | BOU | 11 hr |
| Oct 11, 2:48 PM MDT | Red Flag Warning | BOU | 27 hr |
| Oct 12, 3:02 PM MDT | Red Flag Warning | BOU | 27 hr |
| Oct 13, 1:54 PM MDT | Red Flag Warning | BOU | 28 hr |
| Oct 14, 3:44 PM MDT | Frost Advisory | BOU | 17 hr |
| Oct 15, 3:25 PM MDT | Freeze Warning | BOU | 17 hr |
| Oct 23, 2:46 PM MDT | Winter Storm Watch | BOU | 24 hr |
| Oct 24, 2:41 PM MDT | Winter Weather Advisory | BOU | 39 hr |
| Nov 5, 4:02 AM MST | Fire Weather Watch | BOU | 9 hr |
| Nov 5, 1:03 PM MST | Red Flag Warning | BOU | 28 hr |
| Nov 6, 2:45 PM MST | High Wind Watch | BOU | 14 hr |
| Nov 7, 5:12 AM MST | High Wind Warning | BOU | 30 hr |
| Nov 8, 4:09 AM MST | Red Flag Warning | BOU | 13 hr |
| Nov 12, 8:51 PM MST | High Wind Watch | BOU | 17 hr |
| Nov 13, 1:45 PM MST | High Wind Warning | BOU | 51 hr |
| Dec 21, 7:52 PM MST | High Wind Watch | BOU | 8 hr |
| Dec 22, 3:48 AM MST | High Wind Warning | BOU | 33 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 | 45 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 10 |
| Mesoscale Discussion | 28 |
| Special Weather Statement | 16 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 4 |
| Cold | |
| Freeze Warning | 2 |
| Frost Advisory | 4 |
| Wind and dust | |
| High Wind Warning | 8 |
| High Wind Watch | 3 |
| Fire | |
| Red Flag Warning | 17 |
| Fire Weather Watch | 5 |
| Fog and smoke | |
| Dense Fog Advisory | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
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.