Alert archive / Illinois / Iroquois County
Weather alerts in Iroquois County, Illinois, 2023
98 weather alerts in 2023, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Iroquois County and its neighbors
Each county as a circle sized by its count in 2023. Tap one for its archive.
- Alerts
- 98
- Warnings
- 22
- Watches
- 19
- Advisories
- 31
- Busiest month
- April16 alerts
- Busiest day
- March 31, 20236 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 2 tornado warnings covering Iroquois County in 2023 had a tornado report inside them; 2 of 2 tornado reports fell inside a warning, on average 32 minutes after it went out.
Iroquois County, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 2 | 1 | 50% | 2 | 100% | 32 min |
| Severe thunderstorm warnings | 6 | 4 | 33% | 7 | 43% | 28 min |
| Flash flood warnings | 1 | 1 | 0% | 1 | 100% | 34 min |
Each office's whole area, 2023
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Chicago, IL: tornado warnings | 32 | 17 | 47% | 68 | 56% | 11 min |
| NWS Chicago, IL: severe thunderstorm warnings | 164 | 106 | 35% | 544 | 84% | 27 min |
| NWS Chicago, IL: flash flood warnings | 19 | 10 | 47% | 42 | 90% | 75 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, 5:16 PM CST | Dense Fog Advisory | LOT | 16 hr |
| Jan 2, 9:04 AM CST | Dense Fog Advisory | LOT | 19 hr |
| Jan 3, 6:19 PM CST | Tornado Warning | LOT | 22 min |
| Jan 3, 6:55 PM CST | Special Weather Statement | LOT | 35 min |
| Jan 19, 8:26 AM CST | Dense Fog Advisory | LOT | 2 hr |
| Jan 24, 1:57 AM CST | Winter Weather Advisory | LOT | 52 hr |
| Jan 30, 12:03 AM CST | Winter Weather Advisory | LOT | 8 hr |
| Feb 7, 2:42 PM CST | High Wind Watch | LOT | 23 hr |
| Feb 8, 2:01 PM CST | Wind Advisory | LOT | 28 hr |
| Feb 9, 6:01 AM CST | Special Weather Statement | LOT | 29 min |
| Feb 14, 4:03 AM CST | Wind Advisory | LOT | 34 hr |
| Feb 22, 9:12 AM CST | River Flood Watch | LOT | 8 hr |
| Feb 22, 9:12 AM CST | River Flood Watch | LOT | 5 days |
| Feb 22, 1:27 PM CST | Areal Flood Advisory | LOT | 11 hr |
| Feb 22, 4:58 PM CST | River Flood Warning | LOT | 70 hr |
| Feb 22, 8:29 PM CST | River Flood Warning | LOT | 15 days |
| Feb 23, 4:19 AM CST | Dense Fog Advisory | LOT | 5 hr |
| Feb 23, 8:08 AM CST | River Flood Watch | LOT | 26 hr |
| Feb 27, 8:46 AM CST | Mesoscale Discussion | SPC | 89 min |
| Feb 27, 9:14 AM CST | Wind Advisory | LOT | 3 hr |
| Feb 27, 10:06 AM CST | Tornado Watch | SPC | 5 hr |
| Mar 2, 2:39 AM CST | Winter Storm Watch | LOT | 18 hr |
| Mar 2, 10:22 AM CST | River Flood Watch | LOT | 33 hr |
| Mar 2, 8:38 PM CST | Winter Storm Warning | LOT | 22 hr |
| Mar 3, 12:29 PM CST | High Wind Warning | LOT | 4 hr |
| Mar 3, 7:47 PM CST | River Flood Warning | LOT | 66 hr |
| Mar 4, 10:24 PM CST | Dense Fog Advisory | LOT | 11 hr |
| Mar 23, 7:50 PM CDT | River Flood Watch | LOT | 39 hr |
| Mar 26, 1:41 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Mar 31, 3:06 AM CDT | Wind Advisory | LOT | 37 hr |
| Mar 31, 2:07 PM CDT | Mesoscale Discussion | SPC | 83 min |
| Mar 31, 2:36 PM CDT | Tornado Watch | SPC | 7 hr |
| Mar 31, 3:50 PM CDT | Mesoscale Discussion | SPC | 55 min |
| Mar 31, 3:53 PM CDT | Special Weather Statement | LOT | 22 min |
| Mar 31, 6:20 PM CDT | Mesoscale Discussion | SPC | 115 min |
| Mar 31, 7:38 PM CDT | Severe Thunderstorm Warning | LOT | 22 min |
| Mar 31, 7:42 PM CDT | Tornado Warning | LOT | 48 min |
| Mar 31, 7:54 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 4, 3:42 PM CDT | Wind Advisory | LOT | 24 hr |
| Apr 5, 3:27 AM CDT | Mesoscale Discussion | SPC | 93 min |
| Apr 5, 3:57 AM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Apr 11, 3:19 AM CDT | Fire Weather Watch | LOT | 23 hr |
| Apr 12, 2:40 AM CDT | Red Flag Warning | LOT | 16 hr |
| Apr 17, 2:43 PM CDT | Freeze Warning | LOT | 17 hr |
| Apr 20, 3:53 AM CDT | Wind Advisory | LOT | 14 hr |
| Apr 20, 5:23 PM CDT | Mesoscale Discussion | SPC | 97 min |
| Apr 20, 7:28 PM CDT | Special Weather Statement | LOT | 32 min |
| Apr 22, 1:56 PM CDT | Freeze Watch | LOT | 13 hr |
| Apr 23, 2:56 AM CDT | Freeze Warning | LOT | 29 hr |
| Apr 25, 1:41 PM CDT | Frost Advisory | LOT | 18 hr |
| Apr 26, 2:28 PM CDT | Frost Advisory | LOT | 17 hr |
| May 7, 1:28 AM CDT | Special Weather Statement | LOT | 32 min |
| May 7, 1:31 AM CDT | Special Weather Statement | LOT | 44 min |
| May 7, 2:00 AM CDT | Severe Thunderstorm Warning | LOT | 60 min |
| May 7, 6:36 PM CDT | Flood Watch | LOT | 8 hr |
| May 7, 6:40 PM CDT | Mesoscale Discussion | SPC | 65 min |
| May 7, 6:58 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 7, 9:06 PM CDT | Dust Storm Warning | LOT | 84 min |
| May 7, 9:16 PM CDT | Severe Thunderstorm Warning | LOT | 89 min |
| May 7, 10:43 PM CDT | Severe Thunderstorm Warning | LOT | 15 min |
| Jun 29, 3:08 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 29, 5:42 AM CDT | Special Weather Statement | LOT | 63 min |
| Jun 29, 6:06 AM CDT | Mesoscale Discussion | SPC | 84 min |
| Jun 29, 10:34 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 29, 12:41 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 29, 1:24 PM CDT | Severe Thunderstorm Warning | LOT | 66 min |
| Jun 30, 4:27 AM CDT | Dense Fog Advisory | LOT | 5 hr |
| Jul 5, 12:49 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Jul 26, 3:50 AM CDT | Heat Advisory | LOT | 65 hr |
| Jul 27, 3:05 AM CDT | Excessive Heat Warning | LOT | 42 hr |
| Jul 27, 4:06 AM CDT | Dense Fog Advisory | LOT | 4 hr |
| Jul 28, 2:52 AM CDT | Mesoscale Discussion | SPC | 113 min |
| Jul 28, 4:50 AM CDT | Severe Thunderstorm Warning | LOT | 55 min |
| Jul 28, 7:21 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 28, 7:30 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 4, 5:17 AM CDT | Dense Fog Advisory | LOT | 3 hr |
| Aug 5, 2:11 AM CDT | Flood Watch | LOT | 18 hr |
| Aug 5, 1:26 PM CDT | Flash Flood Warning | LOT | 3 hr |
| Aug 5, 4:40 PM CDT | Areal Flood Advisory | LOT | 110 min |
| Aug 7, 4:11 AM CDT | Areal Flood Advisory | LOT | 5 hr |
| Aug 9, 12:18 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 12, 6:00 AM CDT | Special Weather Statement | LOT | 30 min |
| Aug 14, 11:13 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 19, 2:47 AM CDT | Heat Advisory | LOT | 41 hr |
| Aug 20, 4:12 PM CDT | Heat Advisory | LOT | 52 hr |
| Aug 21, 2:47 AM CDT | Excessive Heat Watch | LOT | 48 hr |
| Aug 22, 2:59 AM CDT | Excessive Heat Warning | LOT | 65 hr |
| Sep 26, 1:20 PM CDT | Mesoscale Discussion | SPC | 85 min |
| Sep 26, 2:02 PM CDT | Mesoscale Discussion | SPC | 88 min |
| Sep 29, 1:34 AM CDT | Dense Fog Advisory | LOT | 7 hr |
| Oct 9, 2:04 PM CDT | Frost Advisory | LOT | 18 hr |
| Oct 10, 2:18 PM CDT | Frost Advisory | LOT | 18 hr |
| Oct 29, 3:24 AM CDT | Freeze Warning | LOT | 30 hr |
| Oct 30, 8:34 AM CDT | Freeze Warning | LOT | 24 hr |
| Nov 5, 12:33 AM CDT | Dense Fog Advisory | LOT | 10 hr |
| Dec 22, 11:35 PM CST | Dense Fog Advisory | LOT | 12 hr |
| Dec 23, 3:29 PM CST | Dense Fog Advisory | LOT | 21 hr |
| Dec 30, 6:15 PM CST | Winter Weather Advisory | LOT | 17 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 archive20222024
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.