Alert archive / Illinois / DuPage County
Weather alerts in DuPage County, Illinois, 2021
129 weather alerts in 2021, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
DuPage County and its neighbors
Each county as a circle sized by its count in 2021. Tap one for its archive.
- Alerts
- 129
- Warnings
- 32
- Watches
- 18
- Advisories
- 40
- Busiest month
- August36 alerts
- Busiest day
- June 21, 20218 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 5 tornado warnings covering DuPage County in 2021 had a tornado report inside them; 1 of 1 tornado reports fell inside a warning, on average 0 minutes after it went out.
DuPage County, 2021
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 5 | 1 | 80% | 1 | 100% | 0 min |
| Severe thunderstorm warnings | 17 | 14 | 18% | 30 | 93% | 31 min |
| Flash flood warnings | 4 | 2 | 50% | 4 | 100% | 57 min |
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 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, 6:23 PM CST | Mesoscale Discussion | SPC | 4 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 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 27, 5:30 AM CST | Dense Fog Advisory | LOT | 6 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 17, 2:35 PM CDT | Wind Advisory | LOT | 28 hr |
| Mar 25, 3:29 AM CDT | Wind Advisory | LOT | 23 hr |
| Mar 29, 2:56 AM CDT | Wind Advisory | LOT | 22 hr |
| Apr 5, 4:25 AM CDT | Special Weather Statement | LOT | 50 min |
| Apr 7, 2:53 PM CDT | Special Weather Statement | LOT | 52 min |
| 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, 6:37 PM CDT | Severe Thunderstorm Warning | LOT | 38 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 3, 6:32 PM CDT | Special Weather Statement | LOT | 43 min |
| 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 |
| Jun 11, 1:07 PM CDT | Special Weather Statement | LOT | 113 min |
| Jun 12, 1:23 PM CDT | Special Weather Statement | LOT | 112 min |
| Jun 12, 1:26 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 12, 1:52 PM CDT | Severe Thunderstorm Warning | LOT | 68 min |
| Jun 12, 2:26 PM CDT | Severe Thunderstorm Warning | LOT | 41 min |
| Jun 12, 2:37 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Jun 12, 2:55 PM CDT | Severe Thunderstorm Warning | LOT | 65 min |
| Jun 18, 4:34 AM CDT | Special Weather Statement | LOT | 41 min |
| Jun 20, 10:57 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 20, 9:40 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 20, 10:40 PM CDT | Severe Thunderstorm Warning | LOT | 50 min |
| Jun 20, 10:43 PM CDT | Tornado Warning | LOT | 32 min |
| Jun 20, 10:46 PM CDT | Tornado Warning | LOT | 20 min |
| Jun 20, 10:56 PM CDT | Severe Thunderstorm Warning | LOT | 79 min |
| Jun 20, 11:05 PM CDT | Tornado Warning | LOT | 40 min |
| Jun 20, 11:08 PM CDT | Areal Flood Advisory | LOT | 4 hr |
| Jun 20, 11:15 PM CDT | Tornado Warning | LOT | 30 min |
| Jun 24, 2:19 PM CDT | Flash Flood Watch | LOT | 54 hr |
| Jun 25, 8:52 AM CDT | River Flood Advisory | LOT | 22 hr |
| Jun 26, 12:05 PM CDT | Tornado Watch | SPC | 9 hr |
| Jun 26, 12:18 PM CDT | Flash Flood Warning | LOT | 6 hr |
| Jun 26, 6:23 PM CDT | Areal Flood Advisory | LOT | 7 hr |
| Jun 26, 9:28 PM CDT | River Flood Advisory | LOT | 23 hr |
| Jun 28, 3:01 AM CDT | Flash Flood Watch | LOT | 40 hr |
| Jun 28, 1:49 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Jul 7, 2:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Jul 14, 2:01 PM CDT | Mesoscale Discussion | SPC | 119 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 24, 3:54 PM CDT | Severe Thunderstorm Warning | LOT | 51 min |
| Jul 24, 5:21 PM CDT | Mesoscale Discussion | SPC | 114 min |
| 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, 2:14 AM CDT | Severe Thunderstorm Warning | LOT | 76 min |
| Jul 29, 3:18 AM CDT | Mesoscale Discussion | SPC | 87 min |
| Aug 6, 3:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Aug 8, 5:58 PM CDT | Special Weather Statement | LOT | 32 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 9, 6:24 PM CDT | Tornado Warning | LOT | 66 min |
| Aug 9, 7:18 PM CDT | Severe Thunderstorm Warning | LOT | 42 min |
| Aug 10, 3:07 PM CDT | Heat Advisory | LOT | 28 hr |
| Aug 10, 3:47 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 10, 5:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 10, 6:34 PM CDT | Severe Thunderstorm Warning | LOT | 86 min |
| Aug 10, 6:55 PM CDT | Severe Thunderstorm Warning | LOT | 95 min |
| Aug 11, 8:34 AM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 11, 8:52 AM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 11, 9:25 AM CDT | Severe Thunderstorm Warning | LOT | 65 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, 8:57 PM CDT | Severe Thunderstorm Warning | LOT | 48 min |
| Aug 11, 9:43 PM CDT | Severe Thunderstorm Warning | LOT | 26 min |
| Aug 11, 11:06 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Aug 12, 3:43 AM CDT | Special Weather Statement | LOT | 47 min |
| 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, 5:13 PM CDT | Special Weather Statement | LOT | 32 min |
| 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 25, 5:42 PM CDT | Severe Thunderstorm Warning | LOT | 33 min |
| Aug 25, 6:23 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Aug 25, 6:29 PM CDT | Severe Thunderstorm Warning | LOT | 31 min |
| Aug 25, 7:21 PM CDT | Flash Flood Warning | LOT | 3 hr |
| Aug 25, 8:54 PM CDT | Areal Flood Advisory | LOT | 17 min |
| Aug 25, 9:06 PM CDT | Flash Flood Warning | LOT | 5 hr |
| 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, 3:14 PM CDT | Mesoscale Discussion | SPC | 91 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 13, 12:21 AM CDT | Dense Fog Advisory | LOT | 8 hr |
| Oct 22, 1:29 PM CDT | Frost Advisory | LOT | 19 hr |
| Oct 23, 12:46 PM CDT | Flash Flood Watch | LOT | 38 hr |
| Oct 24, 3:10 AM CDT | Wind Advisory | LOT | 36 hr |
| Oct 25, 3:02 AM CDT | River Flood Advisory | LOT | 36 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.
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.