Alert archive / South Carolina / Sumter County
Weather alerts in Sumter County, South Carolina, 2017
150 weather alerts in 2017, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Sumter County and its neighbors
Each county as a circle sized by its count in 2017. Tap one for its archive.
- Alerts
- 150
- Warnings
- 44
- Watches
- 13
- Advisories
- 48
- Busiest month
- May30 alerts
- Busiest day
- April 5, 20178 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
1 of 3 tornado warnings covering Sumter County in 2017 had a tornado report inside them.
Sumter County, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 1 | 67% | 0 | ||
| Severe thunderstorm warnings | 33 | 20 | 39% | 25 | 88% | 25 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2017
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Columbia, SC: tornado warnings | 29 | 12 | 59% | 33 | 85% | 11 min |
| NWS Columbia, SC: severe thunderstorm warnings | 205 | 135 | 34% | 331 | 85% | 23 min |
| NWS Columbia, SC: flash flood warnings | 19 | 13 | 32% | 40 | 93% | 36 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, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 3, 1:39 AM EST | Special Weather Statement | CAE | 66 min |
| Jan 3, 2:51 AM EST | Special Weather Statement | CAE | 39 min |
| Jan 7, 3:44 AM EST | Lake Wind Advisory | CAE | 14 hr |
| Jan 16, 10:51 PM EST | Dense Fog Advisory | CAE | 11 hr |
| Jan 21, 1:53 AM EST | Dense Fog Advisory | CAE | 9 hr |
| Jan 22, 3:26 AM EST | Lake Wind Advisory | CAE | 43 hr |
| Jan 22, 6:58 PM EST | Mesoscale Discussion | SPC | 92 min |
| Jan 25, 2:16 PM EST | Lake Wind Advisory | CAE | 29 hr |
| Jan 29, 2:50 AM EST | Lake Wind Advisory | CAE | 16 hr |
| Feb 8, 2:32 PM EST | Lake Wind Advisory | CAE | 28 hr |
| Feb 15, 10:06 AM EST | Special Weather Statement | CAE | 54 min |
| Feb 15, 10:35 AM EST | Severe Thunderstorm Warning | CAE | 40 min |
| Feb 25, 3:56 AM EST | Lake Wind Advisory | CAE | 18 hr |
| Mar 1, 3:11 AM EST | Lake Wind Advisory | CAE | 24 hr |
| Mar 1, 10:39 PM EST | Special Weather Statement | CAE | 2 hr |
| Mar 3, 3:13 AM EST | Freeze Warning | CAE | 30 hr |
| Mar 4, 9:09 AM EST | Freeze Warning | CAE | 24 hr |
| Mar 11, 2:37 PM EST | Winter Weather Advisory | CAE | 20 hr |
| Mar 12, 5:02 AM EDT | Freeze Warning | CAE | 29 hr |
| Mar 13, 1:36 PM EDT | Freeze Watch | CAE | 14 hr |
| Mar 14, 3:43 AM EDT | Freeze Warning | CAE | 30 hr |
| Mar 14, 3:43 AM EDT | Lake Wind Advisory | CAE | 31 hr |
| Mar 15, 10:28 AM EDT | Freeze Warning | CAE | 24 hr |
| Mar 16, 10:30 AM EDT | Freeze Warning | CAE | 24 hr |
| Mar 19, 2:38 PM EDT | Frost Advisory | CAE | 18 hr |
| Mar 21, 7:47 PM EDT | Mesoscale Discussion | SPC | 58 min |
| Mar 21, 8:35 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Mar 21, 10:34 PM EDT | Severe Thunderstorm Warning | CAE | 41 min |
| Mar 21, 10:51 PM EDT | Severe Thunderstorm Warning | CAE | 39 min |
| Mar 21, 10:58 PM EDT | Severe Thunderstorm Warning | CAE | 47 min |
| Mar 21, 11:18 PM EDT | Mesoscale Discussion | SPC | 57 min |
| Mar 31, 12:53 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 3, 3:52 AM EDT | Lake Wind Advisory | CAE | 20 hr |
| Apr 3, 2:07 PM EDT | Tornado Watch | SPC | 6 hr |
| Apr 3, 4:00 PM EDT | Mesoscale Discussion | SPC | 90 min |
| Apr 3, 4:51 PM EDT | Severe Thunderstorm Warning | CAE | 54 min |
| Apr 3, 4:55 PM EDT | Severe Thunderstorm Warning | CAE | 50 min |
| Apr 3, 5:11 PM EDT | Tornado Warning | CAE | 34 min |
| Apr 3, 5:46 PM EDT | Severe Thunderstorm Warning | CAE | 29 min |
| Apr 5, 4:12 AM EDT | Flash Flood Watch | CAE | 16 hr |
| Apr 5, 10:43 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 5, 12:54 PM EDT | Tornado Watch | SPC | 10 hr |
| Apr 5, 2:43 PM EDT | Wind Advisory | CAE | 30 hr |
| Apr 5, 3:12 PM EDT | Severe Thunderstorm Warning | CAE | 63 min |
| Apr 5, 3:33 PM EDT | Areal Flood Advisory | CAE | 117 min |
| Apr 5, 4:04 PM EDT | Severe Thunderstorm Warning | CAE | 41 min |
| Apr 5, 4:17 PM EDT | Severe Thunderstorm Warning | CAE | 43 min |
| Apr 6, 8:46 PM EDT | Lake Wind Advisory | CAE | 24 hr |
| Apr 20, 3:43 AM EDT | Dense Fog Advisory | CAE | 6 hr |
| Apr 23, 10:59 AM EDT | Flash Flood Watch | CAE | 37 hr |
| Apr 23, 2:24 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 23, 10:32 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 24, 2:28 AM EDT | Areal Flood Advisory | CAE | 62 min |
| Apr 24, 6:32 AM EDT | Areal Flood Advisory | CAE | 118 min |
| Apr 24, 8:56 AM EDT | Areal Flood Advisory | CAE | 64 min |
| Apr 24, 9:37 AM EDT | Areal Flood Advisory | CAE | 53 min |
| Apr 30, 2:22 PM EDT | Lake Wind Advisory | CAE | 30 hr |
| May 1, 7:58 PM EDT | Special Weather Statement | CAE | 62 min |
| May 4, 7:29 PM EDT | Special Weather Statement | CAE | 46 min |
| May 4, 8:20 PM EDT | Special Weather Statement | CAE | 40 min |
| May 4, 8:26 PM EDT | Tornado Warning | CAE | 34 min |
| May 4, 8:49 PM EDT | Tornado Watch | SPC | 6 hr |
| May 4, 11:24 PM EDT | Mesoscale Discussion | SPC | 66 min |
| May 5, 1:19 AM EDT | Areal Flood Advisory | CAE | 116 min |
| May 5, 2:10 AM EDT | Areal Flood Advisory | CAE | 2 hr |
| May 12, 6:33 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 22, 11:16 AM EDT | Flash Flood Watch | CAE | 58 hr |
| May 22, 3:22 PM EDT | Severe Thunderstorm Warning | CAE | 38 min |
| May 23, 2:45 PM EDT | Tornado Watch | SPC | 8 hr |
| May 24, 11:03 AM EDT | Tornado Watch | SPC | 10 hr |
| May 24, 2:10 PM EDT | Mesoscale Discussion | SPC | 95 min |
| May 24, 5:25 PM EDT | Mesoscale Discussion | SPC | 65 min |
| May 25, 1:12 PM EDT | Special Weather Statement | CAE | 48 min |
| May 28, 4:56 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 28, 7:06 PM EDT | Severe Thunderstorm Warning | CAE | 54 min |
| May 28, 7:06 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 28, 7:24 PM EDT | Severe Thunderstorm Warning | CAE | 51 min |
| May 28, 7:53 PM EDT | Severe Thunderstorm Warning | CAE | 52 min |
| May 28, 8:09 PM EDT | Severe Thunderstorm Warning | CAE | 42 min |
| May 28, 8:20 PM EDT | Mesoscale Discussion | SPC | 85 min |
| May 28, 8:44 PM EDT | Severe Thunderstorm Warning | CAE | 31 min |
| May 29, 3:15 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 29, 4:59 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 29, 7:32 PM EDT | Severe Thunderstorm Warning | CAE | 28 min |
| May 29, 7:52 PM EDT | Severe Thunderstorm Warning | CAE | 53 min |
| May 29, 8:40 PM EDT | Severe Thunderstorm Warning | CAE | 35 min |
| May 29, 8:57 PM EDT | Severe Thunderstorm Warning | CAE | 63 min |
| Jun 5, 6:42 PM EDT | Severe Thunderstorm Warning | CAE | 27 min |
| Jun 14, 1:17 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 15, 5:24 PM EDT | Special Weather Statement | CAE | 36 min |
| Jun 15, 6:01 PM EDT | Special Weather Statement | CAE | 29 min |
| Jun 16, 1:27 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 16, 5:52 PM EDT | Special Weather Statement | CAE | 38 min |
| Jun 24, 2:05 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 1, 10:02 PM EDT | Severe Thunderstorm Warning | CAE | 43 min |
| Jul 1, 10:27 PM EDT | Severe Thunderstorm Warning | CAE | 36 min |
| Jul 5, 6:46 PM EDT | Mesoscale Discussion | SPC | 89 min |
| Jul 6, 7:53 PM EDT | Severe Thunderstorm Warning | CAE | 67 min |
| Jul 7, 6:25 PM EDT | Severe Thunderstorm Warning | CAE | 50 min |
| Jul 8, 7:27 PM EDT | Severe Thunderstorm Warning | CAE | 63 min |
| Jul 8, 8:55 PM EDT | Severe Thunderstorm Warning | CAE | 24 min |
| Jul 15, 1:38 PM EDT | Mesoscale Discussion | SPC | 67 min |
| Jul 16, 2:18 PM EDT | Special Weather Statement | CAE | 27 min |
| Jul 16, 2:57 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 16, 6:39 PM EDT | Areal Flood Advisory | CAE | 2 hr |
| Jul 19, 2:47 PM EDT | Severe Thunderstorm Warning | CAE | 43 min |
| Jul 19, 2:52 PM EDT | Severe Thunderstorm Warning | CAE | 53 min |
| Jul 19, 3:48 PM EDT | Severe Thunderstorm Warning | CAE | 57 min |
| Jul 20, 4:14 PM EDT | Special Weather Statement | CAE | 31 min |
| Jul 22, 2:38 AM EDT | Heat Advisory | CAE | 15 hr |
| Jul 23, 5:41 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Jul 24, 5:49 PM EDT | Special Weather Statement | CAE | 41 min |
| Jul 25, 7:09 PM EDT | Areal Flood Advisory | CAE | 111 min |
| Aug 4, 9:02 PM EDT | Severe Thunderstorm Warning | CAE | 28 min |
| Aug 11, 7:19 AM EDT | Dense Fog Advisory | CAE | 3 hr |
| Aug 14, 7:54 PM EDT | Special Weather Statement | CAE | 36 min |
| Aug 28, 2:47 PM EDT | Lake Wind Advisory | CAE | 13 hr |
| Sep 1, 3:06 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 5, 11:32 PM EDT | Special Weather Statement | CAE | 28 min |
| Sep 6, 1:29 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Sep 6, 1:51 PM EDT | Severe Thunderstorm Warning | CAE | 40 min |
| Sep 6, 4:24 PM EDT | Special Weather Statement | CAE | 36 min |
| Sep 6, 4:28 PM EDT | Severe Thunderstorm Warning | CAE | 47 min |
| Sep 9, 2:52 PM EDT | Lake Wind Advisory | CAE | 24 hr |
| Sep 10, 3:16 PM EDT | Wind Advisory | CAE | 30 hr |
| Sep 11, 8:09 PM EDT | Areal Flood Advisory | CAE | 3 hr |
| Sep 11, 8:54 PM EDT | Lake Wind Advisory | CAE | 5 hr |
| Oct 15, 6:11 AM EDT | Dense Fog Advisory | CAE | 4 hr |
| Oct 16, 2:00 PM EDT | Lake Wind Advisory | CAE | 18 hr |
| Oct 23, 1:07 PM EDT | Mesoscale Discussion | SPC | 113 min |
| Oct 23, 1:13 PM EDT | Tornado Warning | CAE | 29 min |
| Oct 23, 2:00 PM EDT | Tornado Watch | SPC | 8 hr |
| Oct 23, 4:33 PM EDT | Mesoscale Discussion | SPC | 57 min |
| Oct 23, 6:52 PM EDT | Special Weather Statement | CAE | 53 min |
| Oct 23, 6:59 PM EDT | Mesoscale Discussion | SPC | 91 min |
| Oct 29, 3:53 AM EDT | Lake Wind Advisory | CAE | 22 hr |
| Nov 4, 11:42 PM EDT | Dense Fog Advisory | CAE | 10 hr |
| Nov 5, 9:53 PM EST | Dense Fog Advisory | CAE | 12 hr |
| Nov 10, 2:40 AM EST | Freeze Warning | CAE | 30 hr |
| Nov 10, 7:06 PM EST | Lake Wind Advisory | CAE | 18 hr |
| Nov 13, 8:21 AM EST | Dense Fog Advisory | CAE | 3 hr |
| Nov 18, 7:01 PM EST | Lake Wind Advisory | CAE | 12 hr |
| Nov 19, 1:34 PM EST | Frost Advisory | CAE | 15 hr |
| Nov 19, 1:34 PM EST | Freeze Warning | CAE | 19 hr |
| Nov 22, 1:37 AM EST | Dense Fog Advisory | CAE | 8 hr |
| Dec 1, 5:49 AM EST | Dense Fog Advisory | CAE | 5 hr |
| Dec 5, 8:51 AM EST | Dense Fog Advisory | CAE | 2 hr |
| Dec 12, 4:19 AM EST | Lake Wind Advisory | CAE | 24 hr |
| Dec 23, 3:14 AM EST | Lake Wind Advisory | CAE | 15 hr |
| Dec 24, 12:01 PM EST | Lake Wind Advisory | CAE | 19 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 | 33 |
| Tornado Warning | 3 |
| Severe Thunderstorm Watch | 3 |
| Tornado Watch | 6 |
| Mesoscale Discussion | 27 |
| Special Weather Statement | 18 |
| Flooding | |
| Flash Flood Watch | 3 |
| Areal Flood Advisory | 10 |
| Winter | |
| Winter Weather Advisory | 1 |
| Heat | |
| Heat Advisory | 1 |
| Cold | |
| Freeze Warning | 8 |
| Freeze Watch | 1 |
| Frost Advisory | 2 |
| Wind and dust | |
| Lake Wind Advisory | 21 |
| Wind Advisory | 2 |
| Fog and smoke | |
| Dense Fog Advisory | 11 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20162018
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.