Alert archive / Illinois / Lake County
Weather alerts in Lake County, Illinois, 2021
119 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Lake County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 119
- Warnings
- 15
- Watches
- 15
- Advisories
- 43
- Busiest month
- August32 alerts
- Busiest day
- August 24, 20215 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Lake County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 6 | 5 | 17% | 33 | 94% | 36 min |
| Flash flood warnings | 1 | 1 | 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 24, 3:05 AM CST | Winter Storm Watch | LOT | 12 hr |
| Jan 24, 2:55 PM CST | Winter Storm Warning | LOT | 48 hr |
| Jan 24, 3:08 PM CST | Lakeshore Flood Advisory | LOT | 45 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 29, 2:43 PM CST | Lakeshore Flood Advisory | LOT | 60 hr |
| Feb 3, 2:29 PM CST | Winter Weather Advisory | LOT | 46 hr |
| Feb 6, 3:34 AM CST | Wind Chill Advisory | LOT | 32 hr |
| Feb 11, 4:10 PM CST | Winter Weather Advisory | LOT | 12 hr |
| Feb 13, 3:33 AM CST | Wind Chill Advisory | LOT | 56 hr |
| Feb 14, 2:19 PM CST | Winter Storm Warning | LOT | 49 hr |
| Feb 14, 2:19 PM CST | Winter Weather Advisory | LOT | 43 hr |
| Feb 15, 2:52 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 28, 6:29 AM CST | Dense Fog Advisory | LOT | 6 hr |
| Mar 9, 8:46 AM CST | River Flood Advisory | LOT | 52 hr |
| Mar 10, 3:25 AM CST | Wind Advisory | LOT | 23 hr |
| Mar 10, 9:34 PM CST | River Flood Advisory | LOT | 9 hr |
| Mar 11, 6:16 AM CST | River Flood Warning | LOT | 48 hr |
| Mar 11, 8:12 PM CST | River Flood Advisory | LOT | 60 hr |
| Mar 15, 2:58 AM CDT | Winter Weather Advisory | LOT | 16 hr |
| Mar 17, 3:39 AM CDT | Lakeshore Flood Advisory | LOT | 46 hr |
| Mar 17, 2:35 PM CDT | Wind Advisory | LOT | 28 hr |
| Mar 25, 3:29 AM CDT | Wind Advisory | LOT | 23 hr |
| Mar 25, 3:42 AM CDT | Lakeshore Flood Advisory | LOT | 33 hr |
| Mar 29, 2:56 AM CDT | Wind Advisory | LOT | 22 hr |
| Apr 7, 3:20 PM CDT | Special Weather Statement | LOT | 40 min |
| 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, 6:01 PM CDT | Special Weather Statement | LOT | 59 min |
| Apr 29, 6:44 PM CDT | Special Weather Statement | LOT | 46 min |
| Apr 30, 2:50 PM CDT | Wind Advisory | LOT | 28 hr |
| May 7, 2:07 PM CDT | Frost Advisory | LOT | 18 hr |
| May 10, 2:23 PM CDT | Frost Advisory | LOT | 18 hr |
| May 11, 2:11 PM CDT | Frost Advisory | LOT | 17 hr |
| May 12, 2:41 PM CDT | Frost Advisory | LOT | 16 hr |
| May 24, 1:43 AM CDT | Dense Fog Advisory | LOT | 4 hr |
| May 26, 9:19 PM CDT | Beach Hazards Statement | LOT | 3 days |
| Jun 12, 1:23 PM CDT | Special Weather Statement | LOT | 112 min |
| Jun 12, 1:26 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 15, 2:54 AM CDT | Beach Hazards Statement | LOT | 28 hr |
| Jun 18, 4:07 AM CDT | Special Weather Statement | LOT | 23 min |
| Jun 20, 9:40 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 20, 11:08 PM CDT | Areal Flood Advisory | LOT | 4 hr |
| Jun 28, 3:01 AM CDT | Flash Flood Watch | LOT | 40 hr |
| Jun 30, 4:01 AM CDT | Beach Hazards Statement | LOT | 59 hr |
| Jul 7, 2:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 10, 11:06 AM CDT | Beach Hazards Statement | LOT | 40 hr |
| Jul 14, 2:01 PM CDT | Mesoscale Discussion | SPC | 119 min |
| Jul 15, 2:14 AM CDT | Mesoscale Discussion | SPC | 61 min |
| Jul 19, 3:52 PM CDT | Beach Hazards Statement | LOT | 44 hr |
| Jul 24, 3:00 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 24, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jul 24, 3:34 PM CDT | Special Weather Statement | LOT | 41 min |
| Jul 28, 4:32 AM CDT | Special Weather Statement | LOT | 43 min |
| Jul 28, 3:44 PM CDT | Beach Hazards Statement | LOT | 51 hr |
| Jul 29, 12:32 AM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 29, 1:00 AM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jul 29, 1:34 AM CDT | Mesoscale Discussion | SPC | 86 min |
| Jul 29, 1:49 AM CDT | Severe Thunderstorm Warning | LOT | 71 min |
| Jul 31, 2:51 AM CDT | Beach Hazards Statement | LOT | 52 hr |
| Aug 6, 3:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Aug 6, 8:49 PM CDT | Special Weather Statement | LOT | 56 min |
| Aug 8, 4:07 PM CDT | Special Weather Statement | LOT | 38 min |
| Aug 8, 6:20 PM CDT | Special Weather Statement | LOT | 25 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, 5:53 PM CDT | Mesoscale Discussion | SPC | 67 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, 6:34 PM CDT | Severe Thunderstorm Warning | LOT | 86 min |
| Aug 11, 8:52 AM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 11, 9:46 AM CDT | Severe Thunderstorm Warning | LOT | 59 min |
| Aug 11, 9:52 AM CDT | Mesoscale Discussion | SPC | 83 min |
| 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 20, 5:23 AM CDT | Dense Fog Advisory | LOT | 3 hr |
| Aug 21, 10:08 AM CDT | Beach Hazards Statement | LOT | 39 hr |
| Aug 24, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Aug 24, 4:58 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Aug 24, 6:13 PM CDT | Beach Hazards Statement | LOT | 4 hr |
| Aug 24, 6:19 PM CDT | Areal Flood Advisory | LOT | 17 min |
| Aug 24, 6:36 PM CDT | Flash Flood Warning | LOT | 3 hr |
| Aug 24, 7:08 PM CDT | Severe Thunderstorm Warning | LOT | 67 min |
| Aug 24, 7:31 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Aug 29, 1:18 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Aug 29, 1:40 PM CDT | Special Weather Statement | LOT | 35 min |
| Aug 29, 2:20 PM CDT | Special Weather Statement | LOT | 40 min |
| Aug 29, 3:02 PM CDT | Special Weather Statement | LOT | 43 min |
| Aug 30, 7:06 PM CDT | Beach Hazards Statement | LOT | 63 hr |
| 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, 1:20 PM CDT | Severe Thunderstorm Warning | LOT | 55 min |
| Sep 7, 2:15 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Sep 7, 2:15 PM CDT | Severe Thunderstorm Warning | LOT | 30 min |
| Sep 17, 2:53 PM CDT | Beach Hazards Statement | LOT | 28 hr |
| Sep 20, 2:39 PM CDT | Beach Hazards Statement | LOT | 4 days |
| Sep 27, 3:10 AM CDT | Beach Hazards Statement | LOT | 34 hr |
| 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 22, 1:29 PM CDT | Frost Advisory | LOT | 19 hr |
| Oct 23, 2:51 PM CDT | Lakeshore Flood Advisory | LOT | 56 hr |
| Oct 24, 3:10 AM CDT | Wind Advisory | LOT | 36 hr |
| Oct 28, 9:08 PM CDT | Lakeshore Flood Advisory | LOT | 34 hr |
| Oct 31, 2:37 AM CDT | Freeze Warning | LOT | 30 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 27, 8:11 AM CST | Dense Fog Advisory | LOT | 4 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 | 6 |
| Severe Thunderstorm Watch | 8 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 20 |
| Special Weather Statement | 13 |
| Flooding | |
| Flash Flood Warning | 1 |
| River Flood Warning | 1 |
| Flash Flood Watch | 1 |
| Areal Flood Advisory | 5 |
| River Flood Advisory | 3 |
| Winter | |
| Winter Storm Warning | 3 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 5 |
| Heat | |
| Heat Advisory | 2 |
| Cold | |
| Freeze Warning | 3 |
| Freeze Watch | 1 |
| Frost Advisory | 5 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| High Wind Warning | 1 |
| High Wind Watch | 1 |
| Wind Advisory | 8 |
| Fog and smoke | |
| Dense Fog Advisory | 7 |
| Coast and beach | |
| Lakeshore Flood Advisory | 6 |
| Beach Hazards Statement | 13 |
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.