Alert archive / Illinois / Lee County
Weather alerts in Lee County, Illinois, 2021
108 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Lee County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 108
- Warnings
- 22
- Watches
- 19
- Advisories
- 31
- Busiest month
- August31 alerts
- Busiest day
- August 10, 20217 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 Lee County in 2021 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 2 minutes after it went out.
Lee County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 3 | 1 | 67% | 1 | 100% | 2 min |
| Severe thunderstorm warnings | 10 | 8 | 20% | 18 | 67% | 32 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Chicago, IL: tornado warnings | 41 | 12 | 71% | 25 | 56% | 16 min |
| NWS Chicago, IL: severe thunderstorm warnings | 116 | 75 | 35% | 398 | 87% | 31 min |
| NWS Chicago, IL: flash flood warnings | 11 | 7 | 36% | 27 | 96% | 106 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, 3:04 PM CST | Dense Fog Advisory | LOT | 20 hr |
| Jan 3, 3:37 PM CST | Dense Fog Advisory | LOT | 29 hr |
| Jan 5, 3:18 PM CST | Dense Fog Advisory | LOT | 19 hr |
| Jan 24, 3:05 AM CST | Winter Storm Watch | LOT | 12 hr |
| Jan 24, 2:55 PM CST | Winter Storm Warning | LOT | 48 hr |
| Jan 29, 3:23 AM CST | Winter Storm Watch | LOT | 24 hr |
| Jan 29, 2:38 PM CST | Winter Storm Warning | LOT | 51 hr |
| Jan 30, 3:27 AM CST | Winter Weather Advisory | LOT | 39 hr |
| Jan 30, 6:23 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Feb 3, 3:03 AM CST | Winter Storm Watch | LOT | 11 hr |
| Feb 3, 5:47 AM CST | Dense Fog Advisory | LOT | 5 hr |
| Feb 3, 2:29 PM CST | Winter Storm Warning | LOT | 36 hr |
| Feb 3, 2:29 PM CST | Winter Weather Advisory | LOT | 46 hr |
| Feb 5, 2:24 PM CST | Winter Weather Advisory | LOT | 31 hr |
| Feb 6, 3:34 AM CST | Wind Chill Advisory | LOT | 32 hr |
| Feb 8, 11:13 AM CST | Winter Weather Advisory | LOT | 16 hr |
| Feb 8, 3:10 PM CST | Wind Chill Advisory | LOT | 19 hr |
| Feb 13, 3:33 AM CST | Wind Chill Warning | LOT | 31 hr |
| Feb 13, 3:33 AM CST | Wind Chill Advisory | LOT | 56 hr |
| Feb 14, 2:19 PM CST | Winter Weather Advisory | LOT | 43 hr |
| Feb 28, 6:29 AM CST | Dense Fog Advisory | LOT | 6 hr |
| Mar 10, 3:25 AM CST | Wind Advisory | LOT | 23 hr |
| Mar 15, 2:58 AM CDT | Winter Weather Advisory | LOT | 16 hr |
| Mar 17, 2:35 PM CDT | Wind Advisory | LOT | 28 hr |
| Mar 29, 2:56 AM CDT | Wind Advisory | LOT | 22 hr |
| Mar 29, 4:25 AM CDT | Red Flag Warning | LOT | 16 hr |
| Apr 19, 3:45 AM CDT | Freeze Watch | LOT | 11 hr |
| Apr 19, 2:58 PM CDT | Freeze Warning | LOT | 42 hr |
| Apr 21, 3:22 AM CDT | Freeze Warning | LOT | 29 hr |
| Apr 29, 5:06 PM CDT | Special Weather Statement | LOT | 54 min |
| Apr 30, 2:50 PM CDT | Wind Advisory | LOT | 28 hr |
| May 3, 4:39 PM CDT | Special Weather Statement | LOT | 66 min |
| May 7, 2:07 PM CDT | Frost Advisory | LOT | 18 hr |
| May 11, 2:11 PM CDT | Frost Advisory | LOT | 17 hr |
| Jun 7, 4:07 PM CDT | Special Weather Statement | LOT | 23 min |
| Jun 11, 1:07 PM CDT | Special Weather Statement | LOT | 113 min |
| Jun 11, 3:36 PM CDT | Severe Thunderstorm Warning | LOT | 54 min |
| Jun 17, 8:48 AM CDT | Special Weather Statement | LOT | 42 min |
| Jun 20, 10:57 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 8:10 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 20, 9:54 PM CDT | Mesoscale Discussion | SPC | 66 min |
| Jun 24, 2:19 PM CDT | Flash Flood Watch | LOT | 54 hr |
| Jun 28, 3:01 AM CDT | Flash Flood Watch | LOT | 40 hr |
| Jul 7, 2:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 14, 2:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jul 14, 11:17 PM CDT | Mesoscale Discussion | SPC | 58 min |
| Jul 14, 11:57 PM CDT | Severe Thunderstorm Watch | SPC | 3 hr |
| Jul 15, 12:39 AM CDT | Special Weather Statement | LOT | 51 min |
| Jul 15, 2:14 AM CDT | Mesoscale Discussion | SPC | 61 min |
| Jul 24, 3:00 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 24, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 29, 12:32 AM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 29, 1:00 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 6, 3:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Aug 9, 12:18 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 9, 2:43 PM CDT | Tornado Watch | SPC | 9 hr |
| Aug 9, 2:46 PM CDT | Heat Advisory | LOT | 28 hr |
| Aug 9, 5:11 PM CDT | Tornado Warning | LOT | 49 min |
| Aug 9, 5:53 PM CDT | Mesoscale Discussion | SPC | 67 min |
| Aug 9, 6:00 PM CDT | Tornado Warning | LOT | 26 min |
| Aug 10, 3:07 PM CDT | Heat Advisory | LOT | 28 hr |
| Aug 10, 3:10 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 10, 3:47 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 10, 5:21 PM CDT | Special Weather Statement | LOT | 54 min |
| Aug 10, 5:39 PM CDT | Severe Thunderstorm Warning | LOT | 81 min |
| Aug 10, 5:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 10, 6:10 PM CDT | Severe Thunderstorm Warning | LOT | 65 min |
| Aug 11, 8:25 AM CDT | Severe Thunderstorm Warning | LOT | 50 min |
| Aug 11, 8:34 AM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 11, 8:41 AM CDT | Severe Thunderstorm Warning | LOT | 49 min |
| Aug 11, 8:52 AM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 11, 7:35 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Aug 11, 8:22 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 11, 11:06 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 23, 2:52 PM CDT | Special Weather Statement | LOT | 38 min |
| Aug 23, 3:06 PM CDT | Severe Thunderstorm Warning | LOT | 24 min |
| Aug 23, 3:47 PM CDT | Special Weather Statement | LOT | 43 min |
| Aug 24, 3:19 AM CDT | Heat Advisory | LOT | 17 hr |
| Aug 24, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 24, 5:10 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 24, 5:26 PM CDT | Severe Thunderstorm Warning | LOT | 64 min |
| Aug 24, 6:09 PM CDT | Severe Thunderstorm Warning | LOT | 66 min |
| Aug 25, 4:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Aug 29, 1:18 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Sep 7, 12:25 PM CDT | Mesoscale Discussion | SPC | 65 min |
| Sep 7, 1:12 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Sep 7, 1:13 PM CDT | Special Weather Statement | LOT | 32 min |
| Sep 7, 1:23 PM CDT | Severe Thunderstorm Warning | LOT | 67 min |
| Sep 20, 10:07 PM CDT | Special Weather Statement | LOT | 38 min |
| Sep 20, 10:48 PM CDT | Special Weather Statement | LOT | 42 min |
| Oct 8, 5:52 AM CDT | Dense Fog Advisory | LOT | 3 hr |
| Oct 8, 9:45 PM CDT | Dense Fog Advisory | LOT | 6 hr |
| Oct 11, 12:37 PM CDT | Mesoscale Discussion | SPC | 113 min |
| Oct 11, 3:10 PM CDT | Tornado Watch | SPC | 6 hr |
| Oct 11, 6:09 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Oct 11, 6:44 PM CDT | Severe Thunderstorm Warning | LOT | 61 min |
| Oct 11, 6:49 PM CDT | Tornado Warning | LOT | 13 min |
| Oct 22, 1:29 PM CDT | Frost Advisory | LOT | 19 hr |
| Oct 31, 2:37 AM CDT | Freeze Warning | LOT | 30 hr |
| Nov 27, 8:13 AM CST | Winter Weather Advisory | LOT | 3 hr |
| Dec 3, 10:49 PM CST | Dense Fog Advisory | LOT | 3 hr |
| Dec 5, 1:54 PM CST | Wind Advisory | LOT | 22 hr |
| Dec 10, 2:56 AM CST | Wind Advisory | LOT | 36 hr |
| Dec 14, 3:19 AM CST | High Wind Watch | LOT | 24 hr |
| Dec 15, 3:09 AM CST | High Wind Warning | LOT | 30 hr |
| Dec 15, 9:44 PM CST | Severe Thunderstorm Watch | SPC | 3 hr |
| Dec 27, 2:03 PM CST | Winter Weather Advisory | LOT | 28 hr |
| Dec 28, 8:59 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 | 10 |
| Tornado Warning | 3 |
| Severe Thunderstorm Watch | 10 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 24 |
| Special Weather Statement | 12 |
| Flooding | |
| Flash Flood Watch | 2 |
| Winter | |
| Winter Storm Warning | 3 |
| Winter Storm Watch | 3 |
| Winter Weather Advisory | 8 |
| Heat | |
| Heat Advisory | 3 |
| Cold | |
| Freeze Warning | 3 |
| Wind Chill Warning | 1 |
| Freeze Watch | 1 |
| Frost Advisory | 3 |
| Wind Chill Advisory | 3 |
| Wind and dust | |
| High Wind Warning | 1 |
| High Wind Watch | 1 |
| Wind Advisory | 6 |
| Fire | |
| Red Flag Warning | 1 |
| Fog and smoke | |
| Dense Fog Advisory | 8 |
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.