Alert archive / South Dakota / Union County
Weather alerts in Union County, South Dakota, 2012
95 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Union County and its neighbors
Each county as a circle sized by its count in 2012. Tap one for its archive.
- Alerts
- 95
- Warnings
- 21
- Watches
- 16
- Advisories
- 36
- Busiest month
- May36 alerts
- Busiest day
- May 27, 20127 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Union County, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 7 | 7 | 0% | 6 | 83% | 14 min |
| Flash flood warnings | 2 | 1 | 50% | 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 18, 3:15 PM CST | Winter Weather Advisory | FSD | 47 hr |
| Jan 22, 3:30 AM CST | Winter Weather Advisory | FSD | 27 hr |
| Jan 24, 2:47 PM CST | Winter Weather Advisory | FSD | 11 hr |
| Jan 25, 8:27 AM CST | Dense Fog Advisory | FSD | 4 hr |
| Feb 1, 9:43 PM CST | Winter Storm Watch | FSD | 14 hr |
| Feb 5, 11:52 PM CST | Dense Fog Advisory | FSD | 11 hr |
| Feb 12, 2:08 PM CST | Winter Weather Advisory | FSD | 22 hr |
| Feb 13, 8:59 PM CST | Dense Fog Advisory | FSD | 13 hr |
| Feb 19, 3:43 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Feb 22, 4:02 PM CST | Winter Storm Warning | FSD | 29 hr |
| Feb 22, 4:09 PM CST | Wind Advisory | FSD | 26 hr |
| Feb 22, 10:39 PM CST | Winter Weather Advisory | FSD | 22 hr |
| Feb 25, 8:49 PM CST | Wind Advisory | FSD | 21 hr |
| Feb 28, 6:18 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Feb 28, 2:30 PM CST | Wind Advisory | FSD | 28 hr |
| Mar 3, 2:50 PM CST | Wind Advisory | FSD | 27 hr |
| Mar 16, 5:35 AM CDT | Dense Fog Advisory | FSD | 5 hr |
| Mar 26, 3:28 AM CDT | Wind Advisory | FSD | 40 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 14, 7:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Apr 15, 7:42 PM CDT | High Wind Warning | FSD | 10 hr |
| Apr 27, 10:41 AM CDT | Wind Advisory | FSD | 11 hr |
| May 1, 2:30 PM CDT | Mesoscale Discussion | SPC | 60 min |
| May 1, 2:59 PM CDT | Tornado Watch | SPC | 6 hr |
| May 2, 3:34 PM CDT | Mesoscale Discussion | SPC | 86 min |
| May 2, 10:43 PM CDT | Mesoscale Discussion | SPC | 62 min |
| May 4, 1:50 PM CDT | Mesoscale Discussion | SPC | 25 min |
| May 4, 2:00 PM CDT | Severe Thunderstorm Watch | SPC | 9 hr |
| May 4, 3:00 PM CDT | Severe Thunderstorm Warning | FSD | 30 min |
| May 4, 3:52 PM CDT | Mesoscale Discussion | SPC | 53 min |
| May 4, 9:54 PM CDT | Mesoscale Discussion | SPC | 96 min |
| May 5, 6:49 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 5, 2:09 PM CDT | Mesoscale Discussion | SPC | 96 min |
| May 5, 3:06 PM CDT | Flash Flood Watch | FSD | 13 hr |
| May 5, 3:52 PM CDT | Mesoscale Discussion | SPC | 83 min |
| May 5, 5:31 PM CDT | Tornado Watch | SPC | 5 hr |
| May 5, 10:03 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 6, 4:45 AM CDT | River Flood Warning | FSD | 7 days |
| May 6, 4:45 AM CDT | River Flood Warning | FSD | 7 days |
| May 21, 2:51 PM CDT | Wind Advisory | FSD | 29 hr |
| May 23, 3:50 AM CDT | Flash Flood Watch | FSD | 29 hr |
| May 23, 2:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 23, 4:07 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 23, 8:56 PM CDT | Mesoscale Discussion | SPC | 94 min |
| May 24, 9:14 AM CDT | River Flood Warning | FSD | 24 hr |
| May 24, 9:14 AM CDT | River Flood Warning | FSD | 24 hr |
| May 27, 3:42 AM CDT | Flash Flood Watch | FSD | 24 hr |
| May 27, 2:58 PM CDT | Mesoscale Discussion | SPC | 62 min |
| May 27, 3:42 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 27, 5:27 PM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| May 27, 6:43 PM CDT | River Flood Warning | FSD | 5 days |
| May 27, 6:43 PM CDT | River Flood Warning | FSD | 6 days |
| May 27, 6:55 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 27, 7:11 PM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| May 27, 7:22 PM CDT | Flash Flood Warning | FSD | 7 hr |
| May 27, 9:18 PM CDT | Severe Thunderstorm Warning | FSD | 27 min |
| May 27, 9:32 PM CDT | Flash Flood Warning | FSD | 4 hr |
| May 27, 9:42 PM CDT | Severe Thunderstorm Warning | FSD | 10 min |
| Jun 19, 7:01 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 23, 1:18 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Jun 26, 2:53 PM CDT | Heat Advisory | FSD | 29 hr |
| Jun 29, 7:59 AM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 1, 3:24 PM CDT | Heat Advisory | FSD | 5 days |
| Jul 4, 3:31 PM CDT | Excessive Heat Warning | FSD | 51 hr |
| Jul 5, 5:52 PM CDT | Mesoscale Discussion | SPC | 53 min |
| 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 25, 2:52 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Aug 1, 3:52 AM CDT | Heat Advisory | FSD | 15 hr |
| Aug 1, 8:19 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Aug 3, 6:19 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 3, 7:33 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 15, 2:56 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Aug 26, 2:25 AM CDT | Dense Fog Advisory | FSD | 9 hr |
| Sep 4, 7:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Sep 4, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Sep 4, 8:14 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Sep 4, 8:57 PM CDT | Severe Thunderstorm Warning | FSD | 48 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 | Wind Advisory | FSD | 61 hr |
| Oct 16, 2:46 PM CDT | Wind Advisory | FSD | 61 hr |
| Oct 23, 9:40 PM CDT | Dense Fog Advisory | FSD | 6 hr |
| Nov 21, 4:11 AM CST | Wind Advisory | FSD | 50 hr |
| Dec 8, 3:44 PM CST | Wind Advisory | FSD | 29 hr |
| Dec 18, 3:52 PM CST | Winter Weather Advisory | FSD | 44 hr |
| Dec 19, 3:50 PM CST | Winter Weather Advisory | FSD | 12 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 | 7 |
| Severe Thunderstorm Watch | 8 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 22 |
| Flooding | |
| Flash Flood Warning | 2 |
| River Flood Warning | 6 |
| Flash Flood Watch | 3 |
| Winter | |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 9 |
| Heat | |
| Excessive Heat Warning | 1 |
| Heat Advisory | 6 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 2 |
| Wind and dust | |
| High Wind Warning | 1 |
| Wind Advisory | 15 |
| 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 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.