Alert archive / Montana / Sheridan County
Weather alerts in Sheridan County, Montana, 2021
120 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Sheridan County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 120
- Warnings
- 44
- Watches
- 26
- Advisories
- 35
- Busiest month
- June29 alerts
- Busiest day
- July 8, 20217 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Sheridan County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 13 | 9 | 31% | 12 | 83% | 27 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 Glasgow, MT: tornado warnings | 4 | 0 | 100% | 0 | ||
| NWS Glasgow, MT: severe thunderstorm warnings | 87 | 53 | 39% | 188 | 74% | 29 min |
| NWS Glasgow, MT: flash flood warnings | 1 | 1 | 0% | 5 | 20% | 4 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 2, 7:17 AM MST | Winter Weather Advisory | GGW | 7 hr |
| Jan 4, 1:17 PM MST | Winter Weather Advisory | GGW | 23 hr |
| Jan 8, 6:13 PM MST | Dense Fog Advisory | GGW | 19 hr |
| Jan 11, 3:09 AM MST | High Wind Watch | GGW | 33 hr |
| Jan 12, 12:26 PM MST | High Wind Warning | GGW | 55 hr |
| Jan 23, 1:46 PM MST | Wind Chill Advisory | GGW | 45 hr |
| Jan 25, 2:55 PM MST | Wind Chill Advisory | GGW | 44 hr |
| Jan 30, 7:23 PM MST | Dense Fog Advisory | GGW | 16 hr |
| Jan 31, 9:59 PM MST | Dense Fog Advisory | GGW | 5 hr |
| Feb 2, 1:34 PM MST | Winter Weather Advisory | GGW | 23 hr |
| Feb 3, 12:21 PM MST | Wind Chill Advisory | GGW | 22 hr |
| Feb 4, 2:05 PM MST | Wind Chill Watch | GGW | 13 hr |
| Feb 4, 2:05 PM MST | Wind Chill Advisory | GGW | 13 hr |
| Feb 4, 2:05 PM MST | Wind Chill Advisory | GGW | 6 days |
| Feb 7, 2:49 AM MST | Wind Chill Warning | GGW | 7 days |
| Feb 14, 2:26 PM MST | Wind Chill Advisory | GGW | 21 hr |
| Feb 15, 11:58 AM MST | Wind Chill Advisory | GGW | 23 hr |
| Feb 17, 2:29 PM MST | Wind Chill Advisory | GGW | 19 hr |
| Feb 22, 1:42 AM MST | Winter Weather Advisory | GGW | 36 hr |
| Mar 4, 8:10 PM MST | Dense Fog Advisory | GGW | 14 hr |
| Mar 10, 6:43 AM MST | Dense Fog Advisory | GGW | 5 hr |
| Mar 21, 3:14 AM MDT | Red Flag Warning | GGW | 16 hr |
| Mar 26, 3:12 AM MDT | Fire Weather Watch | GGW | 24 hr |
| Mar 27, 3:15 AM MDT | Red Flag Warning | GGW | 41 hr |
| Mar 27, 6:59 AM MDT | Dense Fog Advisory | GGW | 3 hr |
| Mar 27, 2:16 PM MDT | High Wind Watch | GGW | 13 hr |
| Mar 28, 3:11 AM MDT | High Wind Warning | GGW | 45 hr |
| Mar 30, 2:05 PM MDT | Fire Weather Watch | GGW | 25 hr |
| Mar 31, 2:50 PM MDT | Red Flag Warning | GGW | 30 hr |
| Apr 11, 8:34 PM MDT | Winter Weather Advisory | GGW | 57 hr |
| Apr 28, 3:00 PM MDT | Fire Weather Watch | GGW | 24 hr |
| Apr 29, 2:42 PM MDT | Fire Weather Watch | GGW | 37 hr |
| Apr 29, 2:42 PM MDT | Red Flag Warning | GGW | 34 hr |
| May 1, 3:14 AM MDT | Red Flag Warning | GGW | 17 hr |
| May 6, 1:35 PM MDT | Fire Weather Watch | GGW | 14 hr |
| May 7, 3:05 AM MDT | Red Flag Warning | GGW | 17 hr |
| May 7, 1:44 PM MDT | Winter Weather Advisory | GGW | 40 hr |
| May 16, 1:52 PM MDT | Fire Weather Watch | GGW | 14 hr |
| May 17, 3:35 AM MDT | Red Flag Warning | GGW | 17 hr |
| May 29, 5:24 PM MDT | Special Weather Statement | GGW | 51 min |
| Jun 2, 10:52 AM MDT | Fire Weather Watch | GGW | 26 hr |
| Jun 3, 2:32 AM MDT | Heat Advisory | GGW | 18 hr |
| Jun 3, 1:12 PM MDT | Red Flag Warning | GGW | 35 hr |
| Jun 5, 2:55 AM MDT | Red Flag Warning | GGW | 18 hr |
| Jun 6, 3:01 AM MDT | Red Flag Warning | GGW | 17 hr |
| Jun 8, 3:07 AM MDT | Flash Flood Watch | GGW | 24 hr |
| Jun 8, 2:39 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 8, 3:52 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 8, 6:15 PM MDT | Mesoscale Discussion | SPC | 90 min |
| Jun 8, 6:53 PM MDT | Severe Thunderstorm Warning | GGW | 56 min |
| Jun 8, 8:57 PM MDT | Severe Thunderstorm Warning | GGW | 27 min |
| Jun 10, 1:56 PM MDT | Mesoscale Discussion | SPC | 94 min |
| Jun 10, 2:30 PM MDT | Tornado Watch | SPC | 6 hr |
| Jun 10, 3:14 PM MDT | Severe Thunderstorm Warning | GGW | 61 min |
| Jun 10, 3:31 PM MDT | Severe Thunderstorm Warning | GGW | 59 min |
| Jun 10, 4:23 PM MDT | Severe Thunderstorm Warning | GGW | 67 min |
| Jun 10, 4:36 PM MDT | Mesoscale Discussion | SPC | 114 min |
| Jun 10, 7:30 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 10, 8:09 PM MDT | Severe Thunderstorm Warning | GGW | 32 min |
| Jun 10, 8:54 PM MDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 10, 9:05 PM MDT | Special Weather Statement | GGW | 40 min |
| Jun 10, 9:48 PM MDT | Severe Thunderstorm Warning | GGW | 57 min |
| Jun 14, 3:02 AM MDT | Heat Advisory | GGW | 42 hr |
| Jun 14, 3:10 AM MDT | Fire Weather Watch | GGW | 24 hr |
| Jun 14, 1:45 PM MDT | Red Flag Warning | GGW | 56 hr |
| Jun 16, 2:20 PM MDT | Red Flag Warning | GGW | 31 hr |
| Jun 24, 5:15 PM MDT | Severe Thunderstorm Warning | GGW | 46 min |
| Jun 29, 2:30 AM MDT | Excessive Heat Watch | GGW | 24 hr |
| Jun 30, 2:13 AM MDT | Excessive Heat Warning | GGW | 5 days |
| Jul 8, 4:37 AM MDT | Special Weather Statement | GGW | 53 min |
| Jul 8, 5:25 AM MDT | Special Weather Statement | GGW | 50 min |
| Jul 8, 1:35 PM MDT | Severe Thunderstorm Warning | GGW | 55 min |
| Jul 8, 2:26 PM MDT | Severe Thunderstorm Warning | GGW | 64 min |
| Jul 8, 2:34 PM MDT | Mesoscale Discussion | SPC | 86 min |
| Jul 8, 3:21 PM MDT | Severe Thunderstorm Warning | GGW | 54 min |
| Jul 8, 4:14 PM MDT | Severe Thunderstorm Warning | GGW | 61 min |
| Jul 14, 1:30 PM MDT | Excessive Heat Watch | GGW | 44 hr |
| Jul 16, 9:12 AM MDT | Excessive Heat Warning | GGW | 6 days |
| Jul 18, 1:52 PM MDT | Red Flag Warning | GGW | 33 hr |
| Jul 21, 3:05 PM MDT | Fire Weather Watch | GGW | 23 hr |
| Jul 22, 2:16 PM MDT | Red Flag Warning | GGW | 31 hr |
| Jul 22, 4:07 PM MDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 22, 7:11 PM MDT | Severe Thunderstorm Warning | GGW | 64 min |
| Jul 22, 8:04 PM MDT | Mesoscale Discussion | SPC | 116 min |
| Jul 22, 8:28 PM MDT | Special Weather Statement | GGW | 62 min |
| Jul 24, 1:56 PM MDT | Excessive Heat Watch | GGW | 23 hr |
| Jul 25, 1:20 PM MDT | Excessive Heat Warning | GGW | 57 hr |
| Aug 14, 2:37 AM MDT | Fire Weather Watch | GGW | 12 hr |
| Aug 14, 2:12 PM MDT | Red Flag Warning | GGW | 4 days |
| Aug 18, 2:11 AM MDT | Special Weather Statement | GGW | 64 min |
| Aug 27, 2:55 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 4, 2:33 PM MDT | Fire Weather Watch | GGW | 24 hr |
| Sep 5, 2:30 PM MDT | Red Flag Warning | GGW | 30 hr |
| Sep 8, 1:38 PM MDT | Red Flag Warning | GGW | 30 hr |
| Sep 14, 1:08 PM MDT | Red Flag Warning | GGW | 30 hr |
| Sep 16, 2:32 PM MDT | Red Flag Warning | GGW | 55 hr |
| Sep 28, 3:38 AM MDT | Red Flag Warning | GGW | 17 hr |
| Oct 3, 2:57 AM MDT | Fire Weather Watch | GGW | 11 hr |
| Oct 3, 1:27 PM MDT | Red Flag Warning | GGW | 55 hr |
| Oct 5, 3:38 AM MDT | Fire Weather Watch | GGW | 10 hr |
| Oct 5, 2:03 PM MDT | Red Flag Warning | GGW | 29 hr |
| Oct 12, 10:22 AM MDT | Winter Weather Advisory | GGW | 32 hr |
| Nov 13, 12:54 AM MST | Winter Weather Advisory | GGW | 5 hr |
| Nov 14, 2:33 PM MST | High Wind Watch | GGW | 12 hr |
| Nov 15, 2:33 AM MST | High Wind Warning | GGW | 62 hr |
| Dec 2, 1:05 PM MST | Winter Storm Watch | GGW | 14 hr |
| Dec 3, 2:56 AM MST | Winter Storm Warning | GGW | 48 hr |
| Dec 5, 3:06 AM MST | Wind Chill Advisory | GGW | 35 hr |
| Dec 5, 10:14 AM MST | Winter Weather Advisory | GGW | 4 hr |
| Dec 5, 1:46 PM MST | Winter Weather Advisory | GGW | 4 hr |
| Dec 14, 11:19 AM MST | Winter Weather Advisory | GGW | 29 hr |
| Dec 15, 12:41 PM MST | Wind Chill Advisory | GGW | 20 hr |
| Dec 16, 1:31 PM MST | Wind Chill Advisory | GGW | 45 hr |
| Dec 16, 1:31 PM MST | Winter Weather Advisory | GGW | 27 hr |
| Dec 19, 9:52 AM MST | Wind Chill Advisory | GGW | 23 hr |
| Dec 23, 10:16 PM MST | Special Weather Statement | GGW | 59 min |
| Dec 24, 1:27 PM MST | Wind Chill Advisory | GGW | 20 hr |
| Dec 25, 1:02 PM MST | Wind Chill Advisory | GGW | 19 hr |
| Dec 25, 1:02 PM MST | Winter Weather Advisory | GGW | 33 hr |
| Dec 26, 2:13 PM MST | Wind Chill Warning | GGW | 6 days |
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 | 3 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 8 |
| Special Weather Statement | 7 |
| Flooding | |
| Flash Flood Watch | 1 |
| Winter | |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 13 |
| Heat | |
| Excessive Heat Warning | 3 |
| Excessive Heat Watch | 3 |
| Heat Advisory | 2 |
| Cold | |
| Wind Chill Warning | 2 |
| Wind Chill Watch | 1 |
| Wind Chill Advisory | 14 |
| Wind and dust | |
| High Wind Warning | 3 |
| High Wind Watch | 3 |
| Fire | |
| Red Flag Warning | 22 |
| Fire Weather Watch | 13 |
| Fog and smoke | |
| Dense Fog Advisory | 6 |
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.