Alert archive / South Dakota / Gregory County
Weather alerts in Gregory County, South Dakota, 2023
103 weather alerts in 2023, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Gregory County and its neighbors
Each county as a circle sized by its count in 2023. Tap one for its archive.
- Alerts
- 103
- Warnings
- 24
- Watches
- 16
- Advisories
- 37
- Busiest month
- July24 alerts
- Busiest day
- June 24, 20237 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Gregory County, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 12 | 7 | 42% | 4 | 100% | 24 min |
| Flash flood warnings | 1 | 0 | 100% | 0 |
Each office's whole area, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 23 | 6 | 74% | 16 | 50% | 13 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 228 | 126 | 45% | 282 | 82% | 18 min |
| NWS Sioux Falls, SD: flash flood warnings | 9 | 3 | 67% | 12 | 75% | 47 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, Central Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 1, 2:10 PM CST | Winter Storm Warning | FSD | 61 hr |
| Jan 3, 12:06 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 3, 3:04 AM CST | Winter Weather Advisory | FSD | 45 hr |
| Jan 3, 6:09 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 12, 6:49 PM CST | Dense Fog Advisory | FSD | 17 hr |
| Jan 17, 3:11 PM CST | Winter Storm Warning | FSD | 42 hr |
| Jan 20, 10:08 PM CST | Dense Fog Advisory | FSD | 5 hr |
| Jan 26, 3:33 AM CST | Winter Storm Watch | FSD | 24 hr |
| Jan 26, 3:40 AM CST | Wind Advisory | FSD | 29 hr |
| Jan 27, 3:12 AM CST | Winter Storm Warning | FSD | 39 hr |
| Jan 27, 9:51 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 28, 1:41 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Jan 29, 1:48 PM CST | Wind Chill Advisory | FSD | 22 hr |
| Jan 30, 2:28 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Feb 9, 2:50 AM CST | Wind Advisory | FSD | 14 hr |
| Feb 14, 2:51 AM CST | Winter Weather Advisory | FSD | 30 hr |
| Feb 19, 2:50 PM CST | Winter Storm Watch | FSD | 36 hr |
| Feb 21, 2:52 AM CST | Winter Storm Warning | FSD | 57 hr |
| Feb 23, 2:25 PM CST | Wind Chill Advisory | FSD | 20 hr |
| Feb 28, 3:00 PM CST | Wind Advisory | FSD | 21 hr |
| Mar 6, 1:10 AM CST | Dense Fog Advisory | FSD | 8 hr |
| Mar 8, 3:30 AM CST | Winter Weather Advisory | FSD | 45 hr |
| Mar 10, 3:05 AM CST | Winter Weather Advisory | FSD | 36 hr |
| Mar 11, 2:41 PM CST | Wind Advisory | FSD | 18 hr |
| Mar 15, 3:29 AM CDT | Winter Storm Watch | FSD | 12 hr |
| Mar 15, 3:26 PM CDT | Winter Weather Advisory | FSD | 40 hr |
| Mar 25, 2:27 AM CDT | Dense Fog Advisory | FSD | 10 hr |
| Mar 29, 2:39 PM CDT | Winter Storm Watch | FSD | 24 hr |
| Mar 30, 3:01 PM CDT | Blizzard Warning | FSD | 38 hr |
| Mar 30, 3:01 PM CDT | Winter Weather Advisory | FSD | 38 hr |
| Apr 2, 3:03 AM CDT | Winter Storm Watch | FSD | 36 hr |
| Apr 3, 2:42 PM CDT | Winter Weather Advisory | FSD | 45 hr |
| Apr 10, 3:30 AM CDT | Fire Weather Watch | FSD | 10 hr |
| Apr 10, 1:44 PM CDT | Red Flag Warning | FSD | 31 hr |
| Apr 12, 3:16 PM CDT | Red Flag Warning | FSD | 29 hr |
| May 6, 5:32 PM CDT | Mesoscale Discussion | SPC | 88 min |
| May 12, 12:17 PM CDT | Mesoscale Discussion | SPC | 118 min |
| May 12, 1:09 PM CDT | Tornado Watch | SPC | 8 hr |
| Jun 23, 9:07 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Jun 23, 9:24 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 23, 11:18 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Jun 24, 1:53 AM CDT | Flash Flood Warning | FSD | 3 hr |
| Jun 24, 2:52 AM CDT | Severe Thunderstorm Warning | FSD | 38 min |
| Jun 24, 2:53 PM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| Jun 24, 3:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jun 27, 7:26 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 27, 8:29 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jun 27, 9:38 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jul 3, 3:48 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Jul 3, 11:29 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 4, 1:25 AM CDT | Mesoscale Discussion | SPC | 95 min |
| Jul 11, 11:34 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jul 12, 12:10 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 12, 2:39 AM CDT | Mesoscale Discussion | SPC | 96 min |
| Jul 12, 2:43 AM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| Jul 12, 3:27 AM CDT | Severe Thunderstorm Warning | FSD | 48 min |
| Jul 13, 1:58 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 14, 5:34 PM CDT | Severe Thunderstorm Warning | FSD | 41 min |
| Jul 14, 6:06 PM CDT | Severe Thunderstorm Warning | FSD | 39 min |
| Jul 18, 6:20 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 18, 8:43 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Jul 18, 9:33 PM CDT | Severe Thunderstorm Warning | FSD | 57 min |
| Jul 18, 10:15 PM CDT | Severe Thunderstorm Warning | FSD | 30 min |
| Jul 18, 11:12 PM CDT | Severe Thunderstorm Warning | FSD | 38 min |
| Jul 18, 11:27 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Jul 19, 3:56 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 25, 3:13 AM CDT | Heat Advisory | FSD | 17 hr |
| Jul 25, 7:14 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 26, 4:14 AM CDT | Heat Advisory | FSD | 16 hr |
| Jul 26, 2:50 PM CDT | Heat Advisory | FSD | 29 hr |
| Jul 26, 4:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 28, 2:46 AM CDT | Heat Advisory | FSD | 17 hr |
| Aug 10, 3:50 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Aug 10, 4:56 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 10, 6:25 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 18, 2:40 PM CDT | Heat Advisory | FSD | 30 hr |
| Aug 19, 2:45 PM CDT | Excessive Heat Watch | FSD | 24 hr |
| Aug 20, 2:41 PM CDT | Excessive Heat Warning | FSD | 4 days |
| Sep 1, 2:09 PM CDT | Heat Advisory | FSD | 53 hr |
| Sep 7, 2:15 PM CDT | Severe Thunderstorm Warning | FSD | 45 min |
| Sep 21, 12:29 AM CDT | Severe Thunderstorm Warning | FSD | 31 min |
| Sep 21, 2:28 AM CDT | Severe Thunderstorm Warning | FSD | 31 min |
| Sep 26, 6:12 AM CDT | Dense Fog Advisory | FSD | 4 hr |
| Sep 27, 4:19 AM CDT | Dense Fog Advisory | FSD | 7 hr |
| Sep 30, 4:27 AM CDT | Dense Fog Advisory | FSD | 5 hr |
| Oct 5, 3:08 AM CDT | Freeze Watch | FSD | 24 hr |
| Oct 5, 2:26 PM CDT | Wind Advisory | FSD | 23 hr |
| Oct 6, 2:48 AM CDT | Freeze Warning | FSD | 30 hr |
| Oct 11, 3:38 PM CDT | Wind Advisory | FSD | 47 hr |
| Oct 11, 8:50 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 17, 8:25 PM CDT | Wind Advisory | FSD | 20 hr |
| Oct 30, 2:37 PM CDT | Wind Advisory | FSD | 19 hr |
| Nov 13, 2:28 PM CST | Red Flag Warning | FSD | 4 hr |
| Nov 25, 1:22 PM CST | Wind Advisory | FSD | 24 hr |
| Dec 4, 2:45 PM CST | Wind Advisory | FSD | 3 hr |
| Dec 8, 1:57 PM CST | Wind Advisory | FSD | 28 hr |
| Dec 23, 2:51 PM CST | Winter Storm Watch | FSD | 13 hr |
| Dec 24, 3:27 AM CST | Blizzard Warning | FSD | 47 hr |
| Dec 25, 3:41 AM CST | Winter Weather Advisory | FSD | 50 hr |
| Dec 25, 7:00 AM CST | Mesoscale Discussion | SPC | 6 hr |
| Dec 25, 3:31 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 25, 7:56 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Dec 31, 7:44 AM CST | Dense Fog Advisory | FSD | 2 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 | 12 |
| Severe Thunderstorm Watch | 6 |
| Tornado Watch | 1 |
| Mesoscale Discussion | 26 |
| Flooding | |
| Flash Flood Warning | 1 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Warning | 4 |
| Winter Storm Watch | 6 |
| Winter Weather Advisory | 8 |
| Heat | |
| Excessive Heat Warning | 1 |
| Excessive Heat Watch | 1 |
| Heat Advisory | 6 |
| Cold | |
| Freeze Warning | 1 |
| Freeze Watch | 1 |
| Wind Chill Advisory | 4 |
| Wind and dust | |
| Wind Advisory | 11 |
| Fire | |
| Red Flag Warning | 3 |
| Fire Weather Watch | 1 |
| 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 archive20222024
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.