Alert archive / Missouri / Jefferson County
Weather alerts in Jefferson County, Missouri, 2018
111 weather alerts in 2018, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Jefferson County and its neighbors
Each county as a circle sized by its count in 2018. Tap one for its archive.
- Alerts
- 111
- Warnings
- 44
- Watches
- 13
- Advisories
- 29
- Busiest month
- June27 alerts
- Busiest day
- June 26, 20186 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Jefferson County, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 16 | 10 | 38% | 9 | 78% | 18 min |
| Flash flood warnings | 4 | 3 | 25% | 2 | 100% | 163 min |
Each office's whole area, 2018
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS St. Louis, MO: tornado warnings | 20 | 3 | 85% | 19 | 42% | 14 min |
| NWS St. Louis, MO: severe thunderstorm warnings | 218 | 101 | 54% | 375 | 80% | 23 min |
| NWS St. Louis, MO: flash flood warnings | 45 | 19 | 58% | 48 | 85% | 90 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 6, 3:35 AM CST | Winter Weather Advisory | LSX | 44 hr |
| Jan 8, 3:36 PM CST | Dense Fog Advisory | LSX | 20 hr |
| Jan 9, 3:28 PM CST | Dense Fog Advisory | LSX | 18 hr |
| Jan 11, 3:14 AM CST | Winter Weather Advisory | LSX | 27 hr |
| Jan 11, 8:43 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 14, 3:22 PM CST | Wind Chill Advisory | LSX | 45 hr |
| Jan 14, 3:22 PM CST | Winter Weather Advisory | LSX | 21 hr |
| Feb 5, 11:15 AM CST | Winter Weather Advisory | LSX | 13 hr |
| Feb 6, 3:34 AM CST | Winter Weather Advisory | LSX | 25 hr |
| Feb 10, 4:20 AM CST | Winter Weather Advisory | LSX | 29 hr |
| Feb 17, 9:16 AM CST | Winter Weather Advisory | LSX | 4 hr |
| Feb 20, 2:50 PM CST | Winter Weather Advisory | LSX | 44 hr |
| Feb 20, 2:59 PM CST | Flood Watch | LSX | 15 hr |
| Feb 20, 9:18 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 21, 3:33 AM CST | Winter Weather Advisory | LSX | 31 hr |
| Feb 22, 3:24 PM CST | Flood Watch | LSX | 52 hr |
| Feb 24, 4:56 AM CST | Areal Flood Advisory | LSX | 4 hr |
| Feb 24, 7:42 AM CST | River Flood Warning | LSX | 3 days |
| Feb 24, 4:23 PM CST | Flash Flood Warning | LSX | 6 hr |
| Feb 24, 9:50 PM CST | Areal Flood Warning | LSX | 12 hr |
| Feb 25, 8:09 AM CST | River Flood Warning | LSX | 4 days |
| Feb 25, 8:09 AM CST | River Flood Warning | LSX | 4 days |
| Feb 25, 8:09 AM CST | River Flood Warning | LSX | 4 days |
| Feb 25, 8:21 PM CST | River Flood Warning | LSX | 5 days |
| Mar 25, 3:16 PM CDT | Flood Watch | LSX | 54 hr |
| Mar 29, 4:18 PM CDT | River Flood Warning | LSX | 64 hr |
| Mar 29, 4:18 PM CDT | River Flood Warning | LSX | 4 days |
| Mar 29, 7:59 PM CDT | River Flood Warning | LSX | 71 hr |
| Mar 29, 8:06 PM CDT | River Flood Warning | LSX | 49 hr |
| Mar 31, 3:36 PM CDT | Winter Weather Advisory | LSX | 30 hr |
| Apr 2, 10:46 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Apr 2, 11:13 PM CDT | Severe Thunderstorm Warning | LSX | 32 min |
| Apr 3, 1:33 PM CDT | Tornado Watch | SPC | 7 hr |
| Apr 3, 2:51 PM CDT | Severe Thunderstorm Warning | LSX | 39 min |
| Apr 13, 5:27 PM CDT | Tornado Watch | SPC | 8 hr |
| Apr 13, 8:42 PM CDT | Mesoscale Discussion | SPC | 63 min |
| Apr 13, 9:53 PM CDT | Severe Thunderstorm Warning | LSX | 67 min |
| Apr 15, 3:52 AM CDT | Freeze Warning | LSX | 29 hr |
| Apr 16, 3:25 AM CDT | Frost Advisory | LSX | 30 hr |
| Apr 16, 3:25 AM CDT | Freeze Warning | LSX | 30 hr |
| Apr 18, 10:24 AM CDT | Wind Advisory | LSX | 9 hr |
| Apr 19, 2:46 AM CDT | Frost Advisory | LSX | 30 hr |
| May 2, 10:20 PM CDT | Mesoscale Discussion | SPC | 115 min |
| May 2, 11:09 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 3, 2:32 AM CDT | Mesoscale Discussion | SPC | 88 min |
| May 14, 1:20 PM CDT | Severe Thunderstorm Watch | SPC | 11 hr |
| May 14, 5:52 PM CDT | Special Weather Statement | LSX | 38 min |
| May 14, 6:29 PM CDT | Severe Thunderstorm Warning | LSX | 61 min |
| May 19, 3:09 PM CDT | Special Weather Statement | LSX | 51 min |
| May 20, 10:55 PM CDT | Special Weather Statement | LSX | 50 min |
| May 27, 3:28 PM CDT | Severe Thunderstorm Warning | LSX | 32 min |
| Jun 2, 9:12 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 2, 8:04 PM CDT | Severe Thunderstorm Warning | LSX | 41 min |
| Jun 9, 10:51 AM CDT | Severe Thunderstorm Warning | LSX | 39 min |
| Jun 9, 11:09 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 14, 5:18 PM CDT | Mesoscale Discussion | SPC | 57 min |
| Jun 14, 5:37 PM CDT | Severe Thunderstorm Warning | LSX | 38 min |
| Jun 14, 6:08 PM CDT | Severe Thunderstorm Warning | LSX | 52 min |
| Jun 14, 6:42 PM CDT | Severe Thunderstorm Warning | LSX | 48 min |
| Jun 14, 7:23 PM CDT | Severe Thunderstorm Warning | LSX | 52 min |
| Jun 15, 3:53 AM CDT | Excessive Heat Warning | LSX | 5 days |
| Jun 25, 3:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Jun 25, 3:32 PM CDT | Excessive Heat Watch | LSX | 36 hr |
| Jun 25, 8:08 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 26, 2:19 AM CDT | Mesoscale Discussion | SPC | 116 min |
| Jun 26, 5:34 AM CDT | Severe Thunderstorm Warning | LSX | 26 min |
| Jun 26, 7:39 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 26, 2:22 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 26, 5:10 PM CDT | Special Weather Statement | LSX | 50 min |
| Jun 27, 3:46 AM CDT | Heat Advisory | LSX | 5 days |
| Jun 28, 2:00 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 28, 8:03 AM CDT | Severe Thunderstorm Warning | LSX | 42 min |
| Jun 28, 8:43 AM CDT | Mesoscale Discussion | SPC | 62 min |
| Jun 28, 1:04 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 28, 3:52 PM CDT | Excessive Heat Warning | LSX | 3 days |
| Jun 28, 5:22 PM CDT | Severe Thunderstorm Warning | LSX | 83 min |
| Jun 28, 7:38 PM CDT | Special Weather Statement | LSX | 37 min |
| Jun 28, 8:07 PM CDT | Flash Flood Warning | LSX | 6 hr |
| Jul 3, 3:31 AM CDT | Heat Advisory | LSX | 64 hr |
| Jul 12, 3:35 AM CDT | Heat Advisory | LSX | 64 hr |
| Jul 27, 1:19 AM CDT | Dense Fog Advisory | LSX | 7 hr |
| Jul 29, 3:25 PM CDT | Severe Thunderstorm Warning | LSX | 50 min |
| Aug 7, 2:45 PM CDT | Severe Thunderstorm Warning | LSX | 45 min |
| Aug 10, 4:56 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 10, 5:56 PM CDT | Special Weather Statement | LSX | 49 min |
| Aug 20, 11:46 AM CDT | Mesoscale Discussion | SPC | 119 min |
| Aug 20, 12:46 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 24, 3:33 PM CDT | Heat Advisory | LSX | 4 days |
| Aug 26, 3:43 AM CDT | Excessive Heat Warning | LSX | 63 hr |
| Sep 6, 3:21 AM CDT | Flash Flood Watch | LSX | 60 hr |
| Sep 6, 11:27 AM CDT | River Flood Warning | LSX | 6 days |
| Sep 7, 8:02 PM CDT | Flash Flood Warning | LSX | 6 hr |
| Sep 7, 8:34 PM CDT | Flash Flood Warning | LSX | 5 hr |
| Sep 8, 1:31 AM CDT | Areal Flood Warning | LSX | 12 hr |
| Sep 8, 8:44 AM CDT | Areal Flood Warning | LSX | 6 hr |
| Sep 8, 1:28 PM CDT | Areal Flood Warning | LSX | 6 hr |
| Sep 9, 7:42 AM CDT | River Flood Warning | LSX | 3 hr |
| Oct 6, 12:39 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 7, 5:33 AM CDT | Dense Fog Advisory | LSX | 3 hr |
| Oct 7, 1:33 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 8, 11:36 AM CDT | River Flood Warning | LSX | 17 days |
| Oct 15, 4:02 AM CDT | Frost Advisory | LSX | 29 hr |
| Oct 20, 3:18 AM CDT | Freeze Warning | LSX | 29 hr |
| Nov 3, 3:03 AM CDT | Dense Fog Advisory | LSX | 6 hr |
| Nov 9, 10:52 AM CST | Winter Weather Advisory | LSX | 10 hr |
| Nov 11, 2:00 PM CST | Winter Weather Advisory | LSX | 36 hr |
| Nov 13, 2:28 PM CST | Winter Storm Watch | LSX | 12 hr |
| Nov 14, 2:32 AM CST | Winter Storm Warning | LSX | 36 hr |
| Nov 14, 2:32 AM CST | Winter Weather Advisory | LSX | 36 hr |
| Nov 25, 11:22 AM CST | Wind Advisory | LSX | 19 hr |
| Dec 15, 8:11 PM CST | River Flood Warning | LSX | 48 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 archive20172019
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.