Alert archive / South Dakota / Gregory County
Weather alerts in Gregory County, South Dakota, 2012
81 weather alerts in 2012, 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 2012. Tap one for its archive.
- Alerts
- 81
- Warnings
- 14
- Watches
- 14
- Advisories
- 31
- Busiest month
- May17 alerts
- Busiest day
- May 5, 20126 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, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 8 | 3 | 63% | 0 | ||
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 21 | 7 | 67% | 15 | 73% | 12 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 230 | 174 | 24% | 342 | 92% | 19 min |
| NWS Sioux Falls, SD: flash flood warnings | 16 | 7 | 56% | 11 | 91% | 103 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 10, 2:38 PM CST | Wind Advisory | FSD | 27 hr |
| Jan 21, 11:08 AM CST | Wind Advisory | FSD | 4 hr |
| Jan 22, 3:30 AM CST | Winter Weather Advisory | FSD | 27 hr |
| Feb 19, 3:43 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 22, 4:09 PM CST | Wind Advisory | FSD | 26 hr |
| Feb 25, 8:49 PM CST | Wind Advisory | FSD | 21 hr |
| Feb 26, 4:06 AM CST | Winter Storm Watch | FSD | 23 hr |
| Feb 27, 3:25 AM CST | Winter Weather Advisory | FSD | 57 hr |
| Mar 2, 3:31 AM CST | Wind Advisory | FSD | 14 hr |
| Mar 3, 2:50 PM CST | Wind Advisory | FSD | 27 hr |
| Mar 17, 3:03 PM CDT | Wind Advisory | FSD | 29 hr |
| Mar 26, 3:28 AM CDT | Wind Advisory | FSD | 40 hr |
| Mar 26, 9:17 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Apr 1, 3:22 AM CDT | Wind Advisory | FSD | 42 hr |
| Apr 5, 3:03 PM CDT | Wind Advisory | FSD | 28 hr |
| Apr 7, 3:15 AM CDT | Wind Advisory | FSD | 16 hr |
| Apr 8, 2:05 PM CDT | Freeze Watch | FSD | 14 hr |
| Apr 9, 3:38 AM CDT | Freeze Warning | FSD | 29 hr |
| Apr 9, 7:41 PM CDT | Freeze Warning | FSD | 37 hr |
| Apr 14, 3:28 PM CDT | Wind Advisory | FSD | 28 hr |
| Apr 15, 5:10 PM CDT | High Wind Warning | FSD | 11 hr |
| Apr 15, 5:10 PM CDT | Wind Advisory | FSD | 3 hr |
| May 1, 3:35 PM CDT | Severe Thunderstorm Warning | FSD | 40 min |
| May 1, 4:58 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 4, 6:49 AM CDT | Mesoscale Discussion | SPC | 116 min |
| May 4, 2:00 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| May 4, 3:52 PM CDT | Mesoscale Discussion | SPC | 53 min |
| May 5, 6:37 AM CDT | Severe Thunderstorm Warning | FSD | 23 min |
| May 5, 6:49 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 5, 6:53 AM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| May 5, 3:06 PM CDT | Flash Flood Watch | FSD | 13 hr |
| May 5, 6:21 PM CDT | Mesoscale Discussion | SPC | 84 min |
| May 5, 6:46 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 5, 7:59 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| May 10, 9:33 PM CDT | Wind Advisory | FSD | 6 hr |
| May 21, 2:51 PM CDT | Wind Advisory | FSD | 29 hr |
| May 22, 2:59 PM CDT | Mesoscale Discussion | SPC | 91 min |
| May 26, 1:58 AM CDT | Mesoscale Discussion | SPC | 92 min |
| May 26, 4:20 AM CDT | Severe Thunderstorm Warning | FSD | 40 min |
| Jun 1, 3:04 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Jun 13, 5:38 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jun 19, 7:01 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 19, 11:20 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 20, 4:00 AM CDT | Mesoscale Discussion | SPC | 60 min |
| Jun 22, 11:43 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jun 23, 1:18 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Jun 25, 4:01 PM CDT | Heat Advisory | FSD | 28 hr |
| Jun 29, 7:59 AM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 1, 3:24 PM CDT | Heat Advisory | FSD | 5 days |
| Jul 13, 3:42 PM CDT | Heat Advisory | FSD | 3 days |
| Jul 17, 3:31 PM CDT | Heat Advisory | FSD | 28 hr |
| Jul 18, 3:54 PM CDT | Heat Advisory | FSD | 6 days |
| Jul 19, 5:42 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jul 19, 7:34 PM CDT | Severe Thunderstorm Warning | FSD | 41 min |
| Jul 19, 7:50 PM CDT | Severe Thunderstorm Warning | FSD | 40 min |
| Jul 21, 10:51 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jul 22, 10:58 PM CDT | Mesoscale Discussion | SPC | 107 min |
| Aug 1, 3:52 AM CDT | Heat Advisory | FSD | 15 hr |
| Aug 1, 2:53 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Aug 1, 3:19 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 1, 7:25 PM CDT | Severe Thunderstorm Warning | FSD | 35 min |
| Aug 3, 1:02 AM CDT | Mesoscale Discussion | SPC | 88 min |
| Aug 3, 2:14 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 3, 6:19 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 14, 3:23 PM CDT | Wind Advisory | FSD | 28 hr |
| Aug 22, 3:48 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Sep 3, 3:24 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Sep 3, 4:03 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 3, 7:18 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Sep 21, 3:41 PM CDT | Freeze Watch | FSD | 11 hr |
| Sep 22, 3:09 AM CDT | Freeze Warning | FSD | 29 hr |
| Oct 3, 3:32 PM CDT | Wind Advisory | FSD | 26 hr |
| Oct 16, 2:46 PM CDT | High Wind Watch | FSD | 24 hr |
| Oct 16, 2:46 PM CDT | Wind Advisory | FSD | 61 hr |
| Oct 16, 2:46 PM CDT | Wind Advisory | FSD | 61 hr |
| Oct 17, 3:51 AM CDT | High Wind Warning | FSD | 42 hr |
| Nov 10, 5:10 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Nov 21, 4:11 AM CST | Wind Advisory | FSD | 50 hr |
| Dec 8, 3:18 PM CST | Blizzard Warning | FSD | 30 hr |
| Dec 8, 3:44 PM CST | Wind Advisory | FSD | 29 hr |
| Dec 26, 3:31 PM CST | Winter Weather Advisory | FSD | 36 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 | 8 |
| Severe Thunderstorm Watch | 9 |
| Mesoscale Discussion | 22 |
| Flooding | |
| Flash Flood Watch | 1 |
| Winter | |
| Blizzard Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 4 |
| Heat | |
| Heat Advisory | 6 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 2 |
| Wind and dust | |
| High Wind Warning | 2 |
| High Wind Watch | 1 |
| Wind Advisory | 21 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20112013
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.