Alert archive / South Dakota / Dewey County
Weather alerts in Dewey County, South Dakota, 2020
142 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Dewey County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 142
- Warnings
- 55
- Watches
- 16
- Advisories
- 38
- Busiest month
- July45 alerts
- Busiest day
- July 22, 202012 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Dewey County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 42 | 19 | 55% | 14 | 100% | 24 min |
| Flash flood warnings | 2 | 0 | 100% | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Aberdeen, SD: tornado warnings | 11 | 3 | 73% | 16 | 19% | 6 min |
| NWS Aberdeen, SD: severe thunderstorm warnings | 262 | 160 | 39% | 356 | 78% | 19 min |
| NWS Aberdeen, SD: flash flood warnings | 4 | 1 | 75% | 1 | 100% | 205 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, 12:29 PM MST | Wind Advisory | ABR | 23 hr |
| Jan 15, 2:54 AM MST | Wind Chill Advisory | ABR | 32 hr |
| Jan 17, 2:31 AM MST | High Wind Warning | ABR | 26 hr |
| Jan 18, 2:38 AM MST | Wind Chill Advisory | ABR | 8 hr |
| Jan 18, 2:38 AM MST | Wind Chill Advisory | ABR | 32 hr |
| Jan 24, 2:55 AM MST | Dense Fog Advisory | ABR | 31 hr |
| Jan 26, 12:16 PM MST | Winter Weather Advisory | ABR | 11 hr |
| Jan 28, 7:10 PM MST | Dense Fog Advisory | ABR | 16 hr |
| Jan 29, 2:02 PM MST | Dense Fog Advisory | ABR | 21 hr |
| Feb 8, 2:24 AM MST | Winter Weather Advisory | ABR | 26 hr |
| Feb 8, 9:28 AM MST | Winter Storm Warning | ABR | 21 hr |
| Feb 11, 1:38 PM MST | Wind Chill Advisory | ABR | 43 hr |
| Feb 11, 1:38 PM MST | Winter Weather Advisory | ABR | 27 hr |
| Feb 17, 12:14 AM MST | Dense Fog Advisory | ABR | 8 hr |
| Feb 24, 2:05 AM MST | Winter Weather Advisory | ABR | 28 hr |
| Mar 3, 8:37 AM MST | Wind Advisory | ABR | 8 hr |
| Mar 4, 1:44 PM MST | Wind Advisory | ABR | 27 hr |
| Mar 4, 3:51 PM MST | Mesoscale Discussion | SPC | 114 min |
| Mar 27, 7:56 AM MDT | Dense Fog Advisory | ABR | 3 hr |
| Apr 1, 3:00 AM MDT | Winter Weather Advisory | ABR | 51 hr |
| Apr 1, 1:44 PM MDT | Winter Storm Warning | ABR | 24 hr |
| Apr 8, 2:14 AM MDT | Wind Advisory | ABR | 17 hr |
| Apr 20, 2:34 AM MDT | Wind Advisory | ABR | 15 hr |
| Apr 27, 1:54 PM MDT | Wind Advisory | ABR | 30 hr |
| May 8, 8:36 PM MDT | Wind Advisory | ABR | 23 hr |
| May 23, 6:53 PM MDT | Mesoscale Discussion | SPC | 97 min |
| May 24, 2:55 AM MDT | Areal Flood Warning | ABR | 6 hr |
| Jun 2, 3:56 AM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 4, 2:27 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 6, 2:33 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Jun 6, 4:49 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 6, 7:29 PM MDT | Mesoscale Discussion | SPC | 91 min |
| Jun 6, 8:24 PM MDT | Severe Thunderstorm Warning | ABR | 51 min |
| Jun 6, 8:36 PM MDT | Severe Thunderstorm Warning | ABR | 39 min |
| Jun 6, 9:12 PM MDT | Severe Thunderstorm Warning | ABR | 48 min |
| Jun 7, 7:15 PM MDT | Severe Thunderstorm Warning | ABR | 34 min |
| Jun 7, 9:50 PM MDT | Severe Thunderstorm Warning | ABR | 25 min |
| Jun 14, 1:20 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jun 14, 2:20 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 16, 2:16 AM MDT | Wind Advisory | ABR | 18 hr |
| Jun 16, 9:09 PM MDT | Severe Thunderstorm Warning | ABR | 38 min |
| Jun 16, 9:27 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 21, 1:05 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 2:41 PM MDT | Heat Advisory | ABR | 28 hr |
| Jun 28, 7:09 PM MDT | Mesoscale Discussion | SPC | 66 min |
| Jun 28, 7:55 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 28, 8:09 PM MDT | Severe Thunderstorm Warning | ABR | 44 min |
| Jun 28, 9:11 PM MDT | Severe Thunderstorm Warning | ABR | 49 min |
| Jun 28, 10:16 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Jul 2, 1:15 PM MDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 2, 5:16 PM MDT | Mesoscale Discussion | SPC | 119 min |
| Jul 2, 5:59 PM MDT | Severe Thunderstorm Warning | ABR | 46 min |
| Jul 2, 6:46 PM MDT | Severe Thunderstorm Warning | ABR | 44 min |
| Jul 2, 7:07 PM MDT | Severe Thunderstorm Warning | ABR | 38 min |
| Jul 4, 3:30 AM MDT | Severe Thunderstorm Warning | ABR | 45 min |
| Jul 4, 6:01 AM MDT | Severe Thunderstorm Warning | ABR | 44 min |
| Jul 5, 2:32 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Jul 5, 3:41 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 5, 5:29 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 5, 11:14 PM MDT | Special Weather Statement | ABR | 31 min |
| Jul 7, 7:02 PM MDT | Mesoscale Discussion | SPC | 118 min |
| Jul 7, 7:17 PM MDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 10, 8:13 AM MDT | Mesoscale Discussion | SPC | 62 min |
| Jul 10, 12:26 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 10, 1:08 PM MDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 10, 2:43 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 16, 1:23 PM MDT | Heat Advisory | ABR | 30 hr |
| Jul 20, 11:16 AM MDT | Mesoscale Discussion | SPC | 119 min |
| Jul 20, 12:13 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 20, 12:28 PM MDT | Severe Thunderstorm Warning | ABR | 62 min |
| Jul 20, 1:21 PM MDT | Severe Thunderstorm Warning | ABR | 54 min |
| Jul 22, 5:38 AM MDT | Severe Thunderstorm Warning | ABR | 67 min |
| Jul 22, 7:07 AM MDT | Severe Thunderstorm Warning | ABR | 38 min |
| Jul 22, 7:08 AM MDT | Severe Thunderstorm Warning | ABR | 52 min |
| Jul 22, 7:09 AM MDT | Severe Thunderstorm Warning | ABR | 36 min |
| Jul 22, 7:44 AM MDT | Severe Thunderstorm Warning | ABR | 12 min |
| Jul 22, 7:47 AM MDT | Severe Thunderstorm Warning | ABR | 43 min |
| Jul 22, 7:49 AM MDT | Mesoscale Discussion | SPC | 86 min |
| Jul 22, 8:04 AM MDT | Flash Flood Warning | ABR | 3 hr |
| Jul 22, 8:10 AM MDT | Severe Thunderstorm Warning | ABR | 50 min |
| Jul 22, 8:46 AM MDT | Severe Thunderstorm Warning | ABR | 44 min |
| Jul 22, 9:12 AM MDT | Flash Flood Warning | ABR | 3 hr |
| Jul 22, 11:02 AM MDT | Areal Flood Warning | ABR | 3 hr |
| Jul 23, 2:03 AM MDT | Heat Advisory | ABR | 65 hr |
| Jul 24, 1:50 PM MDT | Mesoscale Discussion | SPC | 115 min |
| Jul 24, 2:21 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 24, 6:28 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 25, 7:34 PM MDT | Severe Thunderstorm Warning | ABR | 25 min |
| Jul 31, 1:54 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 31, 3:48 PM MDT | Severe Thunderstorm Warning | ABR | 27 min |
| Jul 31, 4:23 PM MDT | Severe Thunderstorm Warning | ABR | 37 min |
| Jul 31, 4:36 PM MDT | Special Weather Statement | ABR | 39 min |
| Jul 31, 4:57 PM MDT | Severe Thunderstorm Warning | ABR | 48 min |
| Jul 31, 5:04 PM MDT | Severe Thunderstorm Warning | ABR | 41 min |
| Aug 6, 4:01 AM MDT | Dense Fog Advisory | ABR | 5 hr |
| Aug 7, 12:10 AM MDT | Severe Thunderstorm Warning | ABR | 50 min |
| Aug 11, 6:50 AM MDT | Severe Thunderstorm Warning | ABR | 25 min |
| Aug 11, 7:06 AM MDT | Severe Thunderstorm Warning | ABR | 24 min |
| Aug 11, 5:59 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 6:38 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 11, 9:03 PM MDT | Mesoscale Discussion | SPC | 117 min |
| Aug 11, 10:34 PM MDT | Special Weather Statement | ABR | 56 min |
| Aug 11, 11:26 PM MDT | Special Weather Statement | ABR | 64 min |
| Aug 11, 11:36 PM MDT | Mesoscale Discussion | SPC | 84 min |
| Aug 11, 11:43 PM MDT | Severe Thunderstorm Warning | ABR | 47 min |
| Aug 18, 2:28 AM MDT | Severe Thunderstorm Warning | ABR | 27 min |
| Aug 18, 3:33 AM MDT | Severe Thunderstorm Warning | ABR | 57 min |
| Aug 23, 4:10 PM MDT | Mesoscale Discussion | SPC | 95 min |
| Aug 25, 2:23 AM MDT | Heat Advisory | ABR | 17 hr |
| Aug 26, 2:48 PM MDT | Severe Thunderstorm Warning | ABR | 42 min |
| Aug 26, 2:59 PM MDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 26, 3:01 PM MDT | Severe Thunderstorm Warning | ABR | 44 min |
| Aug 26, 3:27 PM MDT | Severe Thunderstorm Warning | ABR | 48 min |
| Aug 26, 4:13 PM MDT | Severe Thunderstorm Warning | ABR | 47 min |
| Aug 26, 4:18 PM MDT | Severe Thunderstorm Warning | ABR | 57 min |
| Aug 26, 5:11 PM MDT | Severe Thunderstorm Warning | ABR | 30 min |
| Aug 27, 5:31 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 27, 8:20 PM MDT | Mesoscale Discussion | SPC | 85 min |
| Aug 27, 8:38 PM MDT | Severe Thunderstorm Warning | ABR | 37 min |
| Aug 27, 9:54 PM MDT | Severe Thunderstorm Warning | ABR | 36 min |
| Sep 2, 2:24 AM MDT | Wind Advisory | ABR | 24 hr |
| Sep 8, 2:29 PM MDT | Freeze Warning | ABR | 18 hr |
| Sep 26, 12:44 PM MDT | Wind Advisory | ABR | 3 hr |
| Sep 29, 1:30 PM MDT | Wind Advisory | ABR | 30 hr |
| Oct 12, 5:51 PM MDT | Wind Advisory | ABR | 4 hr |
| Oct 13, 2:52 PM MDT | High Wind Warning | ABR | 27 hr |
| Oct 20, 3:13 PM MDT | Winter Storm Watch | ABR | 23 hr |
| Oct 21, 2:08 PM MDT | Winter Storm Warning | ABR | 30 hr |
| Oct 21, 8:56 PM MDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 23, 2:13 AM MDT | Winter Storm Watch | ABR | 11 hr |
| Oct 23, 1:35 PM MDT | Winter Storm Warning | ABR | 43 hr |
| Oct 30, 2:40 AM MDT | High Wind Watch | ABR | 10 hr |
| Oct 30, 12:47 PM MDT | Wind Advisory | ABR | 30 hr |
| Oct 31, 10:47 AM MDT | High Wind Warning | ABR | 8 hr |
| Nov 7, 12:21 PM MST | Wind Advisory | ABR | 29 hr |
| Nov 13, 1:05 PM MST | Wind Advisory | ABR | 31 hr |
| Dec 11, 4:48 AM MST | Dense Fog Advisory | ABR | 6 hr |
| Dec 11, 7:35 PM MST | Dense Fog Advisory | ABR | 15 hr |
| Dec 20, 2:22 AM MST | Wind Advisory | ABR | 17 hr |
| Dec 21, 1:01 PM MST | High Wind Watch | ABR | 25 hr |
| Dec 22, 1:23 PM MST | Winter Weather Advisory | ABR | 24 hr |
| Dec 22, 1:31 PM MST | High Wind Warning | ABR | 24 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 | 42 |
| Severe Thunderstorm Watch | 12 |
| Mesoscale Discussion | 29 |
| Special Weather Statement | 4 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 2 |
| Winter | |
| Winter Storm Warning | 4 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 6 |
| Heat | |
| Heat Advisory | 4 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Advisory | 4 |
| Wind and dust | |
| High Wind Warning | 4 |
| High Wind Watch | 2 |
| Wind Advisory | 16 |
| Fog and smoke | |
| Dense Fog Advisory | 8 |
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.