Alert archive / Wyoming / Niobrara County
Weather alerts in Niobrara County, Wyoming, 2021
106 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Niobrara County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 106
- Warnings
- 33
- Watches
- 15
- Advisories
- 15
- Busiest month
- July24 alerts
- Busiest day
- June 9, 20216 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
1 of 1 tornado warnings covering Niobrara County in 2021 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 29 minutes after it went out.
Niobrara County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 1 | 0% | 1 | 100% | 29 min |
| Severe thunderstorm warnings | 17 | 7 | 59% | 8 | 63% | 15 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Cheyenne, WY: tornado warnings | 5 | 1 | 80% | 9 | 11% | 29 min |
| NWS Cheyenne, WY: severe thunderstorm warnings | 144 | 82 | 43% | 200 | 78% | 20 min |
| NWS Cheyenne, WY: flash flood warnings | 13 | 9 | 31% | 19 | 84% | 35 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 11, 12:27 AM MST | High Wind Warning | CYS | 5 days |
| Jan 11, 2:31 AM MST | High Wind Watch | CYS | 55 hr |
| Jan 22, 12:46 PM MST | Winter Weather Advisory | CYS | 38 hr |
| Feb 8, 1:52 PM MST | Wind Chill Advisory | CYS | 19 hr |
| Feb 9, 1:47 PM MST | Wind Chill Advisory | CYS | 3 days |
| Feb 10, 3:30 PM MST | Winter Storm Warning | CYS | 4 days |
| Feb 10, 3:30 PM MST | Winter Weather Advisory | CYS | 4 days |
| Feb 13, 12:49 PM MST | Wind Chill Warning | CYS | 46 hr |
| Mar 8, 3:19 AM MST | Winter Storm Watch | CYS | 22 hr |
| Mar 9, 1:25 AM MST | Winter Storm Warning | CYS | 40 hr |
| Mar 10, 12:12 AM MST | Mesoscale Discussion | SPC | 6 hr |
| Mar 10, 2:15 PM MST | Winter Storm Watch | CYS | 48 hr |
| Mar 11, 2:31 PM MST | Winter Storm Warning | CYS | 3 days |
| Mar 12, 2:11 PM MST | Blizzard Warning | CYS | 59 hr |
| Mar 14, 1:55 AM MST | Mesoscale Discussion | SPC | 6 hr |
| Mar 27, 1:54 PM MDT | High Wind Watch | CYS | 37 hr |
| Mar 27, 1:54 PM MDT | High Wind Warning | CYS | 55 hr |
| Apr 6, 2:55 AM MDT | Winter Weather Advisory | CYS | 23 hr |
| Apr 6, 7:17 PM MDT | Winter Storm Warning | CYS | 14 hr |
| Apr 13, 3:12 AM MDT | Winter Weather Advisory | CYS | 3 days |
| Apr 18, 2:57 AM MDT | Winter Weather Advisory | CYS | 46 hr |
| May 1, 6:29 PM MDT | Special Weather Statement | CYS | 46 min |
| May 13, 3:56 PM MDT | Special Weather Statement | CYS | 49 min |
| May 20, 12:58 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| May 20, 7:27 PM MDT | Severe Thunderstorm Warning | CYS | 35 min |
| May 23, 10:53 AM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 23, 12:06 PM MDT | Tornado Watch | SPC | 8 hr |
| May 23, 1:59 PM MDT | Severe Thunderstorm Warning | CYS | 19 min |
| May 23, 5:25 PM MDT | Mesoscale Discussion | SPC | 95 min |
| May 26, 11:45 AM MDT | Mesoscale Discussion | SPC | 2 hr |
| May 26, 1:27 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 26, 4:14 PM MDT | Special Weather Statement | CYS | 46 min |
| May 26, 4:30 PM MDT | Severe Thunderstorm Warning | CYS | 25 min |
| May 26, 5:02 PM MDT | Special Weather Statement | CYS | 28 min |
| May 28, 6:58 PM MDT | Special Weather Statement | CYS | 47 min |
| May 28, 8:44 PM MDT | Special Weather Statement | CYS | 46 min |
| May 28, 9:05 PM MDT | Severe Thunderstorm Warning | CYS | 40 min |
| May 28, 9:15 PM MDT | Areal Flood Advisory | CYS | 72 min |
| Jun 5, 7:16 PM MDT | Severe Thunderstorm Warning | CYS | 28 min |
| Jun 5, 7:53 PM MDT | Severe Thunderstorm Warning | CYS | 22 min |
| Jun 7, 2:49 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Jun 7, 5:37 PM MDT | Special Weather Statement | CYS | 53 min |
| Jun 8, 5:51 PM MDT | Special Weather Statement | CYS | 39 min |
| Jun 8, 6:37 PM MDT | Mesoscale Discussion | SPC | 83 min |
| Jun 8, 8:21 PM MDT | Special Weather Statement | CYS | 54 min |
| Jun 8, 8:35 PM MDT | Severe Thunderstorm Warning | CYS | 55 min |
| Jun 8, 9:33 PM MDT | Special Weather Statement | CYS | 57 min |
| Jun 9, 2:11 PM MDT | High Wind Watch | CYS | 12 hr |
| Jun 9, 2:11 PM MDT | High Wind Warning | CYS | 39 hr |
| Jun 10, 2:51 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jun 10, 8:27 PM MDT | Special Weather Statement | CYS | 48 min |
| Jun 10, 8:43 PM MDT | Severe Thunderstorm Warning | CYS | 35 min |
| Jun 13, 1:16 PM MDT | Mesoscale Discussion | SPC | 89 min |
| Jun 13, 3:04 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 14, 1:24 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 24, 4:56 PM MDT | Special Weather Statement | CYS | 34 min |
| Jun 24, 6:38 PM MDT | Special Weather Statement | CYS | 22 min |
| Jul 2, 4:59 PM MDT | Special Weather Statement | CYS | 31 min |
| Jul 2, 5:07 PM MDT | Special Weather Statement | CYS | 38 min |
| Jul 2, 5:28 PM MDT | Special Weather Statement | CYS | 47 min |
| Jul 2, 5:42 PM MDT | Severe Thunderstorm Warning | CYS | 48 min |
| Jul 2, 6:30 PM MDT | Severe Thunderstorm Warning | CYS | 30 min |
| Jul 2, 7:00 PM MDT | Severe Thunderstorm Warning | CYS | 60 min |
| Jul 2, 7:05 PM MDT | Special Weather Statement | CYS | 40 min |
| Jul 5, 2:46 PM MDT | Special Weather Statement | CYS | 44 min |
| Jul 7, 2:11 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 7, 2:59 PM MDT | Special Weather Statement | CYS | 31 min |
| Jul 7, 3:58 PM MDT | Severe Thunderstorm Warning | CYS | 47 min |
| Jul 7, 7:15 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 9, 2:16 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 9, 7:25 PM MDT | Severe Thunderstorm Warning | CYS | 50 min |
| Jul 9, 8:04 PM MDT | Severe Thunderstorm Warning | CYS | 41 min |
| Jul 9, 8:31 PM MDT | Tornado Warning | CYS | 44 min |
| Jul 13, 2:21 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Jul 13, 4:25 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 13, 7:35 PM MDT | Mesoscale Discussion | SPC | 85 min |
| Jul 17, 5:25 PM MDT | Special Weather Statement | CYS | 35 min |
| Jul 26, 7:34 PM MDT | Heat Advisory | CYS | 49 hr |
| Jul 30, 12:29 AM MDT | Special Weather Statement | CYS | 61 min |
| Jul 30, 12:54 AM MDT | Areal Flood Advisory | CYS | 3 hr |
| Jul 30, 2:05 AM MDT | Special Weather Statement | CYS | 25 min |
| Aug 6, 1:43 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 6, 3:29 PM MDT | Severe Thunderstorm Warning | CYS | 61 min |
| Aug 6, 4:08 PM MDT | Special Weather Statement | CYS | 52 min |
| Sep 3, 4:14 AM MDT | Special Weather Statement | CYS | 46 min |
| Sep 3, 1:20 PM MDT | Mesoscale Discussion | SPC | 55 min |
| Sep 3, 5:31 PM MDT | Severe Thunderstorm Warning | CYS | 26 min |
| Sep 3, 6:11 PM MDT | Special Weather Statement | CYS | 34 min |
| Sep 3, 6:20 PM MDT | Severe Thunderstorm Warning | CYS | 25 min |
| Sep 3, 6:30 PM MDT | Special Weather Statement | CYS | 30 min |
| Sep 30, 2:24 PM MDT | Frost Advisory | CYS | 18 hr |
| Oct 11, 3:24 AM MDT | Winter Storm Warning | CYS | 57 hr |
| Oct 13, 1:27 AM MDT | Blizzard Warning | CYS | 11 hr |
| Oct 13, 3:58 AM MDT | Mesoscale Discussion | SPC | 6 hr |
| Oct 18, 1:43 PM MDT | Winter Weather Advisory | CYS | 40 hr |
| Oct 26, 8:07 AM MDT | Dense Fog Advisory | CYS | 113 min |
| Oct 30, 2:41 PM MDT | Winter Weather Advisory | CYS | 45 hr |
| Nov 2, 8:11 AM MDT | Dense Fog Advisory | CYS | 4 hr |
| Nov 15, 2:13 AM MST | High Wind Watch | CYS | 23 hr |
| Dec 2, 12:46 PM MST | High Wind Watch | CYS | 62 hr |
| Dec 3, 12:51 PM MST | High Wind Warning | CYS | 52 hr |
| Dec 7, 1:38 PM MST | Winter Storm Watch | CYS | 25 hr |
| Dec 8, 10:37 AM MST | Winter Storm Warning | CYS | 52 hr |
| Dec 14, 4:08 AM MST | High Wind Warning | CYS | 49 hr |
| Dec 25, 1:04 PM MST | High Wind Watch | CYS | 15 hr |
| Dec 25, 1:04 PM MST | High Wind Warning | CYS | 39 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 | 17 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 5 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 17 |
| Special Weather Statement | 26 |
| Flooding | |
| Areal Flood Advisory | 2 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Warning | 6 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 7 |
| Heat | |
| Heat Advisory | 1 |
| Cold | |
| Wind Chill Warning | 1 |
| Frost Advisory | 1 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 6 |
| High Wind Watch | 6 |
| 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 archive20202022
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.