Alert archive / Missouri / Saint Louis County
Weather alerts in Saint Louis County, Missouri, 2021
131 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Saint Louis County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 131
- Warnings
- 48
- Watches
- 17
- Advisories
- 32
- Busiest month
- June26 alerts
- Busiest day
- June 19, 20219 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 Saint Louis County in 2021 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 15 minutes after it went out.
Saint Louis County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 2 | 33% | 1 | 100% | 15 min |
| Severe thunderstorm warnings | 24 | 19 | 21% | 73 | 79% | 29 min |
| Flash flood warnings | 2 | 2 | 0% | 5 | 100% | 46 min |
Each office's whole area, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS St. Louis, MO: tornado warnings | 60 | 17 | 72% | 45 | 71% | 17 min |
| NWS St. Louis, MO: severe thunderstorm warnings | 202 | 106 | 48% | 501 | 73% | 23 min |
| NWS St. Louis, MO: flash flood warnings | 47 | 32 | 32% | 113 | 90% | 98 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 1, 1:08 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Jan 3, 1:55 PM CST | Dense Fog Advisory | LSX | 30 hr |
| Jan 14, 2:33 PM CST | Winter Weather Advisory | LSX | 29 hr |
| Jan 26, 8:19 PM CST | Winter Weather Advisory | LSX | 19 hr |
| Feb 5, 2:19 PM CST | Winter Weather Advisory | LSX | 31 hr |
| Feb 8, 9:18 AM CST | Winter Weather Advisory | LSX | 19 hr |
| Feb 9, 4:02 AM CST | Winter Weather Advisory | LSX | 38 hr |
| Feb 13, 3:24 AM CST | Wind Chill Advisory | LSX | 3 days |
| Feb 13, 2:40 PM CST | Winter Weather Advisory | LSX | 56 hr |
| Feb 14, 2:44 PM CST | Winter Storm Warning | LSX | 31 hr |
| Feb 16, 3:26 AM CST | Winter Weather Advisory | LSX | 39 hr |
| Mar 10, 3:11 AM CST | Wind Advisory | LSX | 15 hr |
| Mar 11, 3:27 AM CST | Flood Watch | LSX | 55 hr |
| Mar 15, 2:49 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Mar 16, 12:58 AM CDT | Dense Fog Advisory | LSX | 9 hr |
| Mar 17, 8:51 AM CDT | Mesoscale Discussion | SPC | 84 min |
| Mar 17, 11:14 AM CDT | River Flood Warning | LSX | 4 days |
| Mar 17, 9:35 PM CDT | River Flood Warning | LSX | 4 days |
| Mar 18, 10:12 AM CDT | River Flood Warning | LSX | 21 days |
| Mar 19, 11:23 AM CDT | River Flood Warning | LSX | 3 days |
| Mar 19, 11:23 AM CDT | River Flood Warning | LSX | 24 hr |
| Mar 23, 12:44 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Mar 25, 3:16 AM CDT | Wind Advisory | LSX | 21 hr |
| Mar 27, 2:34 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Mar 27, 4:44 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Mar 27, 4:52 PM CDT | Severe Thunderstorm Warning | LSX | 38 min |
| Mar 27, 5:26 PM CDT | Severe Thunderstorm Warning | LSX | 38 min |
| Mar 27, 6:16 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Mar 30, 2:43 PM CDT | Freeze Warning | LSX | 42 hr |
| Mar 31, 4:31 AM CDT | Red Flag Warning | LSX | 14 hr |
| Mar 31, 2:44 PM CDT | Freeze Warning | LSX | 42 hr |
| Apr 7, 12:02 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Apr 7, 5:04 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Apr 7, 6:27 PM CDT | Severe Thunderstorm Warning | LSX | 49 min |
| Apr 10, 10:09 AM CDT | Wind Advisory | LSX | 14 hr |
| Apr 10, 9:13 PM CDT | River Flood Warning | LSX | 4 days |
| Apr 11, 9:30 PM CDT | River Flood Warning | LSX | 4 days |
| Apr 18, 2:42 PM CDT | Freeze Watch | LSX | 22 hr |
| Apr 19, 1:01 PM CDT | Freeze Warning | LSX | 23 hr |
| Apr 19, 11:02 PM CDT | Freeze Warning | LSX | 34 hr |
| Apr 21, 3:08 AM CDT | Freeze Warning | LSX | 30 hr |
| May 3, 2:08 PM CDT | Mesoscale Discussion | SPC | 67 min |
| May 3, 2:47 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 3, 4:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| May 3, 5:15 PM CDT | Mesoscale Discussion | SPC | 90 min |
| May 6, 9:52 AM CDT | Mesoscale Discussion | SPC | 83 min |
| May 27, 11:04 AM CDT | Mesoscale Discussion | SPC | 86 min |
| May 27, 11:26 AM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| May 27, 11:50 AM CDT | Severe Thunderstorm Warning | LSX | 55 min |
| May 27, 12:39 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| May 27, 12:57 PM CDT | Mesoscale Discussion | SPC | 93 min |
| May 27, 1:09 PM CDT | Severe Thunderstorm Warning | LSX | 51 min |
| Jun 17, 2:12 PM CDT | Heat Advisory | LSX | 3 days |
| Jun 19, 2:12 PM CDT | Mesoscale Discussion | SPC | 93 min |
| Jun 19, 2:43 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jun 19, 4:16 PM CDT | Severe Thunderstorm Warning | LSX | 44 min |
| Jun 19, 4:43 PM CDT | Severe Thunderstorm Warning | LSX | 47 min |
| Jun 19, 5:09 PM CDT | Severe Thunderstorm Warning | LSX | 51 min |
| Jun 19, 5:11 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Jun 19, 5:17 PM CDT | Severe Thunderstorm Warning | LSX | 43 min |
| Jun 19, 5:25 PM CDT | Severe Thunderstorm Warning | LSX | 35 min |
| Jun 19, 6:00 PM CDT | Severe Thunderstorm Warning | LSX | 45 min |
| Jun 19, 8:00 PM CDT | Severe Thunderstorm Warning | LSX | 21 min |
| Jun 19, 9:49 PM CDT | Mesoscale Discussion | SPC | 56 min |
| Jun 23, 2:00 PM CDT | Flash Flood Watch | LSX | 3 days |
| Jun 24, 11:23 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 24, 11:47 PM CDT | Tornado Watch | SPC | 4 hr |
| Jun 25, 10:06 AM CDT | River Flood Warning | LSX | 21 days |
| Jun 25, 4:46 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 25, 5:06 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 25, 8:34 PM CDT | Mesoscale Discussion | SPC | 86 min |
| Jun 25, 10:31 PM CDT | Mesoscale Discussion | SPC | 59 min |
| Jun 26, 11:42 AM CDT | River Flood Warning | LSX | 8 days |
| Jun 26, 11:45 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 26, 2:47 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 26, 9:34 PM CDT | River Flood Warning | LSX | 3 days |
| Jun 27, 11:36 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 28, 2:05 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| Jul 9, 2:53 AM CDT | Flash Flood Watch | LSX | 47 hr |
| Jul 9, 8:18 PM CDT | Tornado Watch | SPC | 6 hr |
| Jul 9, 8:58 PM CDT | Severe Thunderstorm Warning | LSX | 62 min |
| Jul 9, 9:14 PM CDT | Severe Thunderstorm Warning | LSX | 48 min |
| Jul 9, 10:26 PM CDT | Mesoscale Discussion | SPC | 64 min |
| Jul 9, 11:59 PM CDT | Severe Thunderstorm Warning | LSX | 61 min |
| Jul 10, 12:41 AM CDT | Areal Flood Advisory | LSX | 3 hr |
| Jul 10, 12:42 AM CDT | Severe Thunderstorm Warning | LSX | 63 min |
| Jul 10, 2:01 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 10, 2:15 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| Jul 11, 6:04 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| Jul 23, 3:04 AM CDT | Heat Advisory | LSX | 41 hr |
| Jul 25, 10:11 AM CDT | Flash Flood Warning | LSX | 3 hr |
| Jul 27, 2:47 AM CDT | Heat Advisory | LSX | 66 hr |
| Aug 8, 11:40 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 8, 12:44 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 8, 2:37 PM CDT | Heat Advisory | LSX | 4 days |
| Aug 8, 3:00 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 9, 12:53 AM CDT | Areal Flood Advisory | LSX | 4 hr |
| Aug 10, 3:20 AM CDT | Excessive Heat Warning | LSX | 65 hr |
| Aug 10, 10:45 AM CDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 12, 5:19 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 12, 5:51 PM CDT | Severe Thunderstorm Warning | LSX | 54 min |
| Aug 12, 6:06 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 12, 6:37 PM CDT | Severe Thunderstorm Warning | LSX | 53 min |
| Aug 12, 6:41 PM CDT | Areal Flood Advisory | LSX | 4 hr |
| Aug 22, 2:59 PM CDT | Heat Advisory | LSX | 6 days |
| Aug 23, 3:33 PM CDT | Severe Thunderstorm Warning | LSX | 27 min |
| Aug 26, 2:25 PM CDT | Severe Thunderstorm Warning | LSX | 50 min |
| Aug 26, 3:10 PM CDT | Severe Thunderstorm Warning | LSX | 50 min |
| Aug 30, 2:38 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| Aug 30, 2:54 PM CDT | Flash Flood Warning | LSX | 3 hr |
| Aug 30, 4:04 PM CDT | Areal Flood Advisory | LSX | 3 hr |
| Sep 14, 3:18 PM CDT | Mesoscale Discussion | SPC | 117 min |
| Oct 11, 9:06 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Oct 24, 12:40 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 24, 2:06 PM CDT | Tornado Watch | SPC | 9 hr |
| Oct 24, 5:11 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Oct 24, 9:08 PM CDT | Severe Thunderstorm Warning | LSX | 54 min |
| Nov 2, 2:04 PM CDT | Freeze Warning | LSX | 19 hr |
| Dec 10, 2:28 AM CST | Dense Fog Advisory | LSX | 9 hr |
| Dec 10, 5:17 PM CST | Tornado Watch | SPC | 6 hr |
| Dec 10, 5:27 PM CST | Mesoscale Discussion | SPC | 3 hr |
| Dec 10, 7:02 PM CST | Mesoscale Discussion | SPC | 58 min |
| Dec 10, 7:35 PM CST | Tornado Warning | LSX | 40 min |
| Dec 10, 8:06 PM CST | Tornado Warning | LSX | 39 min |
| Dec 10, 8:29 PM CST | Severe Thunderstorm Warning | LSX | 30 min |
| Dec 10, 9:07 PM CST | Severe Thunderstorm Warning | LSX | 38 min |
| Dec 10, 9:39 PM CST | Tornado Warning | LSX | 51 min |
| Dec 14, 2:20 PM CST | Wind Advisory | LSX | 36 hr |
| Dec 25, 11:55 PM CST | Dense Fog Advisory | LSX | 12 hr |
| Dec 29, 10:09 PM CST | Dense Fog Advisory | LSX | 14 hr |
| Dec 30, 9:23 PM CST | Dense Fog Advisory | LSX | 15 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 | 24 |
| Tornado Warning | 3 |
| Severe Thunderstorm Watch | 9 |
| Tornado Watch | 4 |
| Mesoscale Discussion | 34 |
| Flooding | |
| Flash Flood Warning | 2 |
| River Flood Warning | 10 |
| Flash Flood Watch | 2 |
| Flood Watch | 1 |
| Areal Flood Advisory | 9 |
| Winter | |
| Winter Storm Warning | 1 |
| Winter Weather Advisory | 7 |
| Heat | |
| Excessive Heat Warning | 1 |
| Heat Advisory | 5 |
| Cold | |
| Freeze Warning | 6 |
| Freeze Watch | 1 |
| Wind Chill Advisory | 1 |
| Wind and dust | |
| Wind Advisory | 4 |
| Fire | |
| Red Flag Warning | 1 |
| 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 archive20202022
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.