Alert archive / South Dakota / Gregory County
Weather alerts in Gregory County, South Dakota, 2016
86 weather alerts in 2016, 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 2016. Tap one for its archive.
- Alerts
- 86
- Warnings
- 24
- Watches
- 18
- Advisories
- 16
- Busiest month
- May17 alerts
- Busiest day
- May 23, 20166 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, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 12 | 5 | 58% | 5 | 100% | 17 min |
| Flash flood warnings | 2 | 1 | 50% | 0 |
Each office's whole area, 2016
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 10 | 1 | 90% | 6 | 17% | 6 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 182 | 116 | 36% | 239 | 82% | 17 min |
| NWS Sioux Falls, SD: flash flood warnings | 34 | 13 | 62% | 23 | 100% | 64 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 16, 3:32 AM CST | Wind Chill Advisory | FSD | 53 hr |
| Jan 24, 3:11 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 1, 3:30 PM CST | Winter Weather Advisory | FSD | 33 hr |
| Feb 5, 3:57 AM CST | High Wind Watch | FSD | 35 hr |
| Feb 6, 3:15 PM CST | High Wind Warning | FSD | 30 hr |
| Feb 18, 3:46 AM CST | High Wind Watch | FSD | 11 hr |
| Feb 18, 2:51 PM CST | High Wind Warning | FSD | 21 hr |
| Feb 18, 2:51 PM CST | Wind Advisory | FSD | 24 hr |
| Feb 29, 1:06 PM CST | Mesoscale Discussion | SPC | 24 min |
| Mar 21, 3:37 PM CDT | Winter Storm Watch | FSD | 37 hr |
| Mar 22, 3:19 PM CDT | Winter Storm Warning | FSD | 40 hr |
| Mar 23, 12:08 PM CDT | Mesoscale Discussion | SPC | 6 hr |
| Apr 5, 4:00 PM CDT | Wind Advisory | FSD | 22 hr |
| Apr 6, 2:53 PM CDT | Wind Advisory | FSD | 27 hr |
| May 9, 2:26 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 10, 2:42 PM CDT | Mesoscale Discussion | SPC | 93 min |
| May 10, 3:12 PM CDT | Severe Thunderstorm Warning | FSD | 19 min |
| May 13, 3:44 PM CDT | Frost Advisory | FSD | 17 hr |
| May 22, 7:33 PM CDT | Mesoscale Discussion | SPC | 87 min |
| May 22, 8:22 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 22, 8:34 PM CDT | Severe Thunderstorm Warning | FSD | 41 min |
| May 22, 9:13 PM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| May 22, 10:06 PM CDT | Severe Thunderstorm Warning | FSD | 39 min |
| May 22, 10:45 PM CDT | Flash Flood Warning | FSD | 6 hr |
| May 25, 2:52 PM CDT | Mesoscale Discussion | SPC | 53 min |
| May 25, 6:10 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 25, 6:39 PM CDT | Severe Thunderstorm Warning | FSD | 51 min |
| May 25, 7:23 PM CDT | Severe Thunderstorm Warning | FSD | 52 min |
| May 30, 2:16 PM CDT | Mesoscale Discussion | SPC | 59 min |
| May 30, 2:48 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 30, 6:37 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Jun 9, 3:07 PM CDT | Heat Advisory | FSD | 54 hr |
| Jun 12, 1:41 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 17, 10:33 PM CDT | Severe Thunderstorm Warning | FSD | 42 min |
| Jun 18, 3:14 AM CDT | Heat Advisory | FSD | 41 hr |
| Jun 19, 3:38 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 19, 5:33 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 21, 9:49 PM CDT | Mesoscale Discussion | SPC | 26 min |
| Jun 21, 10:21 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 29, 9:17 PM CDT | Severe Thunderstorm Warning | FSD | 58 min |
| Jul 6, 6:48 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jul 6, 7:38 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 6, 8:45 PM CDT | Severe Thunderstorm Warning | FSD | 30 min |
| Jul 9, 3:07 PM CDT | Heat Advisory | FSD | 24 hr |
| Jul 10, 3:06 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Jul 16, 5:09 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jul 16, 10:58 PM CDT | Severe Thunderstorm Warning | FSD | 32 min |
| Jul 18, 3:57 AM CDT | Excessive Heat Watch | FSD | 24 hr |
| Jul 19, 4:06 AM CDT | Excessive Heat Warning | FSD | 5 days |
| Jul 26, 12:09 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jul 26, 5:32 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jul 26, 6:05 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 26, 7:42 PM CDT | Severe Thunderstorm Warning | FSD | 48 min |
| Jul 26, 8:58 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Jul 30, 7:28 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jul 31, 12:53 AM CDT | Mesoscale Discussion | SPC | 97 min |
| Aug 3, 6:40 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 9, 2:40 PM CDT | Heat Advisory | FSD | 29 hr |
| Aug 11, 6:29 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 11, 9:17 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Aug 14, 5:42 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 14, 6:15 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 14, 9:04 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Aug 18, 3:30 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 18, 9:36 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Sep 4, 4:53 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 4, 9:49 PM CDT | Severe Thunderstorm Warning | FSD | 56 min |
| Sep 4, 10:40 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Sep 5, 3:34 PM CDT | Flash Flood Watch | FSD | 15 hr |
| Sep 6, 2:20 AM CDT | Flash Flood Warning | FSD | 3 hr |
| Sep 8, 7:44 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 3, 3:16 AM CDT | Wind Advisory | FSD | 16 hr |
| Oct 6, 2:43 PM CDT | Frost Advisory | FSD | 18 hr |
| Oct 6, 2:43 PM CDT | Freeze Warning | FSD | 18 hr |
| Oct 11, 2:59 PM CDT | Freeze Watch | FSD | 13 hr |
| Oct 12, 3:39 AM CDT | Freeze Warning | FSD | 29 hr |
| Nov 16, 3:33 AM CST | Winter Storm Watch | FSD | 24 hr |
| Nov 17, 3:34 AM CST | Winter Storm Warning | FSD | 38 hr |
| Nov 18, 2:42 AM CST | Mesoscale Discussion | SPC | 4 hr |
| Dec 14, 3:35 AM CST | Winter Storm Watch | FSD | 32 hr |
| Dec 15, 4:22 AM CST | Winter Storm Warning | FSD | 56 hr |
| Dec 16, 4:02 AM CST | Wind Chill Warning | FSD | 56 hr |
| Dec 20, 8:31 PM CST | Wind Advisory | FSD | 21 hr |
| Dec 25, 3:07 PM CST | Wind Advisory | FSD | 27 hr |
| Dec 25, 8:54 PM CST | High Wind Warning | FSD | 18 hr |
| Dec 25, 8:54 PM CST | Wind Advisory | FSD | 21 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20152017
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.