Alert archive / South Dakota / Gregory County
Weather alerts in Gregory County, South Dakota, 2010
179 weather alerts in 2010, 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 2010. Tap one for its archive.
- Alerts
- 179
- Warnings
- 53
- Watches
- 42
- Advisories
- 33
- Busiest month
- June36 alerts
- Busiest day
- May 24, 20109 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
2 of 3 tornado warnings covering Gregory County in 2010 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 14 minutes after it went out.
Gregory County, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 2 | 33% | 2 | 100% | 14 min |
| Severe thunderstorm warnings | 29 | 17 | 41% | 15 | 80% | 17 min |
| Flash flood warnings | 2 | 2 | 0% | 2 | 50% | 16 min |
Each office's whole area, 2010
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Sioux Falls, SD: tornado warnings | 45 | 20 | 56% | 34 | 91% | 20 min |
| NWS Sioux Falls, SD: severe thunderstorm warnings | 320 | 241 | 25% | 508 | 87% | 20 min |
| NWS Sioux Falls, SD: flash flood warnings | 77 | 62 | 19% | 124 | 91% | 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 2, 4:08 AM CST | Wind Chill Advisory | FSD | 7 hr |
| Jan 5, 3:52 AM CST | Winter Weather Advisory | FSD | 35 hr |
| Jan 5, 2:53 PM CST | Blizzard Watch | FSD | 19 hr |
| Jan 6, 9:59 AM CST | Blizzard Warning | FSD | 23 hr |
| Jan 6, 9:14 PM CST | Wind Chill Warning | FSD | 39 hr |
| Jan 17, 3:14 PM CST | Dense Fog Advisory | FSD | 21 hr |
| Jan 18, 2:35 PM CST | Dense Fog Advisory | FSD | 19 hr |
| Jan 19, 2:21 PM CST | Winter Weather Advisory | FSD | 24 hr |
| Jan 20, 2:44 PM CST | Winter Storm Watch | FSD | 37 hr |
| Jan 22, 3:50 AM CST | Winter Weather Advisory | FSD | 34 hr |
| Jan 24, 3:43 AM CST | Wind Advisory | FSD | 41 hr |
| Jan 24, 6:23 PM CST | Winter Weather Advisory | FSD | 34 hr |
| Feb 3, 3:16 PM CST | Winter Weather Advisory | FSD | 47 hr |
| Feb 7, 4:06 AM CST | Winter Weather Advisory | FSD | 56 hr |
| Feb 13, 3:26 PM CST | Winter Weather Advisory | FSD | 45 hr |
| Mar 2, 9:41 PM CST | Dense Fog Advisory | FSD | 11 hr |
| Mar 5, 7:41 PM CST | Mesoscale Discussion | SPC | 5 hr |
| Mar 9, 3:17 PM CST | Dense Fog Advisory | FSD | 13 hr |
| Mar 10, 4:06 AM CST | Dense Fog Advisory | FSD | 24 hr |
| Mar 11, 4:08 AM CST | Winter Weather Advisory | FSD | 26 hr |
| Apr 1, 11:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Apr 13, 3:15 AM CDT | Wind Advisory | FSD | 19 hr |
| Apr 13, 3:44 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Apr 13, 5:38 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Apr 23, 5:32 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Apr 28, 3:30 AM CDT | Wind Advisory | FSD | 17 hr |
| May 1, 3:08 AM CDT | Wind Advisory | FSD | 16 hr |
| May 4, 4:02 AM CDT | Wind Advisory | FSD | 11 hr |
| May 5, 3:38 AM CDT | Wind Advisory | FSD | 12 hr |
| May 7, 3:38 AM CDT | Freeze Watch | FSD | 12 hr |
| May 7, 3:38 AM CDT | Wind Advisory | FSD | 17 hr |
| May 7, 3:35 PM CDT | Freeze Warning | FSD | 16 hr |
| May 22, 8:52 PM CDT | Tornado Watch | SPC | 4 hr |
| May 22, 9:59 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| May 23, 3:23 PM CDT | Wind Advisory | FSD | 30 hr |
| May 23, 10:19 PM CDT | Mesoscale Discussion | SPC | 86 min |
| May 23, 11:39 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 24, 2:12 AM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| May 24, 3:44 AM CDT | High Wind Warning | FSD | 11 hr |
| May 24, 6:06 AM CDT | Mesoscale Discussion | SPC | 114 min |
| May 24, 2:33 PM CDT | Tornado Watch | SPC | 5 hr |
| May 24, 2:54 PM CDT | Tornado Warning | FSD | 36 min |
| May 24, 3:27 PM CDT | Severe Thunderstorm Warning | FSD | 48 min |
| May 24, 6:03 PM CDT | Mesoscale Discussion | SPC | 87 min |
| May 24, 7:36 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 24, 7:53 PM CDT | Severe Thunderstorm Warning | FSD | 37 min |
| May 24, 8:18 PM CDT | Severe Thunderstorm Warning | FSD | 42 min |
| May 24, 8:28 PM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| May 24, 9:00 PM CDT | Severe Thunderstorm Warning | FSD | 30 min |
| May 29, 2:20 PM CDT | Mesoscale Discussion | SPC | 25 min |
| May 29, 3:25 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 29, 7:04 PM CDT | Severe Thunderstorm Warning | FSD | 41 min |
| May 29, 7:24 PM CDT | Mesoscale Discussion | SPC | 96 min |
| May 29, 7:44 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| May 29, 9:31 PM CDT | Severe Thunderstorm Warning | FSD | 29 min |
| May 29, 9:33 PM CDT | Flash Flood Watch | FSD | 6 hr |
| May 31, 3:22 PM CDT | Mesoscale Discussion | SPC | 113 min |
| May 31, 4:41 PM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| May 31, 5:14 PM CDT | Severe Thunderstorm Warning | FSD | 31 min |
| May 31, 5:44 PM CDT | Severe Thunderstorm Warning | FSD | 32 min |
| Jun 1, 8:26 AM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| Jun 1, 8:44 AM CDT | Flash Flood Warning | FSD | 102 min |
| Jun 1, 8:46 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 1, 12:37 PM CDT | Mesoscale Discussion | SPC | 53 min |
| Jun 3, 3:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 3, 5:57 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 3, 6:29 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jun 3, 7:12 PM CDT | Severe Thunderstorm Warning | FSD | 48 min |
| Jun 3, 9:15 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Jun 10, 1:41 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 10, 3:20 PM CDT | Flash Flood Watch | FSD | 22 hr |
| Jun 10, 7:27 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 11, 3:31 PM CDT | Flash Flood Watch | FSD | 18 hr |
| Jun 12, 6:09 AM CDT | Flash Flood Warning | FSD | 6 hr |
| Jun 12, 12:03 PM CDT | Areal Flood Warning | FSD | 36 hr |
| Jun 14, 12:01 AM CDT | Areal Flood Warning | FSD | 12 hr |
| Jun 14, 12:00 PM CDT | Areal Flood Warning | FSD | 36 hr |
| Jun 16, 12:00 AM CDT | Areal Flood Warning | FSD | 27 hr |
| Jun 17, 3:05 AM CDT | Areal Flood Warning | FSD | 27 hr |
| Jun 18, 6:49 AM CDT | Areal Flood Warning | FSD | 12 hr |
| Jun 18, 6:56 PM CDT | Areal Flood Warning | FSD | 15 hr |
| Jun 19, 9:00 AM CDT | Areal Flood Warning | FSD | 12 hr |
| Jun 19, 10:08 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Jun 19, 10:39 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 20, 9:35 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Jun 20, 9:57 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 21, 4:43 AM CDT | Mesoscale Discussion | SPC | 32 min |
| Jun 21, 9:51 AM CDT | Areal Flood Warning | FSD | 45 hr |
| Jun 22, 11:21 AM CDT | Flash Flood Watch | FSD | 17 hr |
| Jun 22, 7:08 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 22, 7:56 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 22, 9:59 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jun 22, 10:43 PM CDT | Severe Thunderstorm Warning | FSD | 47 min |
| Jun 23, 7:06 AM CDT | Areal Flood Warning | FSD | 15 hr |
| Jun 24, 3:42 AM CDT | Areal Flood Warning | FSD | 42 hr |
| Jun 26, 4:50 PM CDT | Tornado Watch | SPC | 7 hr |
| Jul 3, 3:29 AM CDT | Flash Flood Watch | FSD | 24 hr |
| Jul 3, 5:27 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Jul 3, 6:17 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 3, 8:32 PM CDT | Severe Thunderstorm Warning | FSD | 43 min |
| Jul 3, 8:45 PM CDT | Mesoscale Discussion | SPC | 60 min |
| Jul 3, 9:10 PM CDT | Severe Thunderstorm Warning | FSD | 35 min |
| Jul 3, 10:04 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jul 3, 10:35 PM CDT | Areal Flood Warning | FSD | 9 hr |
| Jul 6, 1:32 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 6, 2:23 PM CDT | Tornado Watch | SPC | 7 hr |
| Jul 6, 5:59 PM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 6, 8:04 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jul 10, 1:36 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 10, 2:27 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 10, 5:17 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jul 17, 4:05 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Jul 17, 4:37 PM CDT | Tornado Watch | SPC | 5 hr |
| Jul 17, 5:50 PM CDT | Severe Thunderstorm Warning | FSD | 16 min |
| Jul 19, 3:00 AM CDT | Mesoscale Discussion | SPC | 60 min |
| Jul 19, 6:31 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 21, 1:22 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Jul 21, 3:27 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 21, 8:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jul 23, 3:43 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 23, 6:58 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jul 23, 7:25 PM CDT | Tornado Warning | FSD | 35 min |
| Jul 23, 7:40 PM CDT | Severe Thunderstorm Warning | FSD | 50 min |
| Jul 23, 7:43 PM CDT | Tornado Warning | FSD | 32 min |
| Jul 23, 8:14 PM CDT | Severe Thunderstorm Warning | FSD | 46 min |
| Jul 23, 8:30 PM CDT | Tornado Watch | SPC | 5 hr |
| Jul 27, 3:09 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 1, 4:49 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 1, 5:15 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 1, 8:03 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Aug 2, 1:44 PM CDT | Mesoscale Discussion | SPC | 61 min |
| Aug 3, 3:02 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Aug 3, 5:56 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 3, 6:55 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Aug 3, 8:58 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Aug 7, 3:43 PM CDT | Heat Advisory | FSD | 48 hr |
| Aug 8, 2:32 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 9, 3:14 PM CDT | Flash Flood Watch | FSD | 24 hr |
| Aug 10, 3:10 AM CDT | Severe Thunderstorm Warning | FSD | 35 min |
| Aug 12, 2:05 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Aug 19, 5:30 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 19, 7:46 PM CDT | Severe Thunderstorm Warning | FSD | 59 min |
| Aug 19, 8:11 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Aug 30, 2:45 PM CDT | Mesoscale Discussion | SPC | 30 min |
| Aug 30, 3:23 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 30, 5:09 PM CDT | Severe Thunderstorm Warning | FSD | 36 min |
| Aug 30, 5:31 PM CDT | Severe Thunderstorm Warning | FSD | 29 min |
| Aug 30, 5:42 PM CDT | Severe Thunderstorm Warning | FSD | 33 min |
| Aug 30, 6:31 PM CDT | Severe Thunderstorm Warning | FSD | 29 min |
| Sep 1, 5:35 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Sep 1, 6:40 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Sep 1, 11:28 PM CDT | Mesoscale Discussion | SPC | 62 min |
| Sep 2, 3:52 AM CDT | Wind Advisory | FSD | 15 hr |
| Sep 5, 2:19 PM CDT | Wind Advisory | FSD | 41 hr |
| Sep 14, 5:43 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Sep 14, 6:22 PM CDT | Tornado Watch | SPC | 4 hr |
| Sep 14, 8:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Sep 14, 9:54 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 20, 8:34 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Sep 22, 8:48 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Sep 22, 11:11 AM CDT | Severe Thunderstorm Warning | FSD | 34 min |
| Sep 22, 4:00 PM CDT | Tornado Watch | SPC | 7 hr |
| Sep 22, 7:41 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 1, 3:02 PM CDT | Frost Advisory | FSD | 18 hr |
| Oct 9, 2:00 PM CDT | Mesoscale Discussion | SPC | 90 min |
| Oct 24, 3:21 PM CDT | High Wind Watch | FSD | 24 hr |
| Oct 25, 3:37 PM CDT | High Wind Watch | FSD | 24 hr |
| Oct 25, 3:37 PM CDT | High Wind Warning | FSD | 51 hr |
| Nov 3, 9:12 AM CDT | Wind Advisory | FSD | 9 hr |
| Nov 20, 7:52 PM CST | Winter Weather Advisory | FSD | 13 hr |
| Nov 23, 2:59 PM CST | Winter Weather Advisory | FSD | 29 hr |
| Nov 28, 4:04 PM CST | Winter Weather Advisory | FSD | 50 hr |
| Dec 10, 2:59 PM CST | Wind Advisory | FSD | 24 hr |
| Dec 10, 10:46 PM CST | Winter Weather Advisory | FSD | 16 hr |
| Dec 11, 3:12 PM CST | Wind Chill Advisory | FSD | 21 hr |
| Dec 29, 3:41 AM CST | Winter Storm Watch | FSD | 36 hr |
| Dec 29, 3:27 PM CST | Winter Storm Warning | FSD | 69 hr |
| Dec 31, 3:53 AM CST | Blizzard Warning | FSD | 32 hr |
| Dec 31, 11:22 AM CST | Mesoscale Discussion | SPC | 5 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 | 29 |
| Tornado Warning | 3 |
| Severe Thunderstorm Watch | 21 |
| Tornado Watch | 9 |
| Mesoscale Discussion | 51 |
| Flooding | |
| Areal Flood Warning | 12 |
| Flash Flood Warning | 2 |
| Flash Flood Watch | 6 |
| Winter | |
| Blizzard Warning | 2 |
| Winter Storm Warning | 1 |
| Blizzard Watch | 1 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 12 |
| Heat | |
| Heat Advisory | 1 |
| Cold | |
| Freeze Warning | 1 |
| Wind Chill Warning | 1 |
| Freeze Watch | 1 |
| Frost Advisory | 1 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 2 |
| High Wind Watch | 2 |
| Wind Advisory | 12 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20092011
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.