Alert archive / Illinois / Grundy County
Weather alerts in Grundy County, Illinois, 2019
151 weather alerts in 2019, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Grundy County and its neighbors
Each county as a circle sized by its count in 2019. Tap one for its archive.
- Alerts
- 151
- Warnings
- 29
- Watches
- 25
- Advisories
- 62
- Busiest month
- May25 alerts
- Busiest day
- September 28, 20199 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Grundy County, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 9 | 4 | 56% | 2 | 100% | 24 min |
| Flash flood warnings | 4 | 1 | 75% | 1 | 100% | 68 min |
Each office's whole area, 2019
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Chicago, IL: tornado warnings | 18 | 3 | 83% | 9 | 44% | 17 min |
| NWS Chicago, IL: severe thunderstorm warnings | 127 | 72 | 43% | 281 | 75% | 24 min |
| NWS Chicago, IL: flash flood warnings | 23 | 9 | 61% | 40 | 57% | 110 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, 6:04 AM CST | Winter Weather Advisory | LOT | 5 hr |
| Jan 7, 2:10 PM CST | Wind Advisory | LOT | 33 hr |
| Jan 11, 3:15 AM CST | Winter Weather Advisory | LOT | 48 hr |
| Jan 14, 1:45 PM CST | Winter Weather Advisory | LOT | 16 hr |
| Jan 17, 12:13 PM CST | Winter Storm Watch | LOT | 15 hr |
| Jan 18, 3:23 AM CST | Winter Storm Warning | LOT | 35 hr |
| Jan 21, 1:57 PM CST | Winter Weather Advisory | LOT | 46 hr |
| Jan 22, 2:36 PM CST | Mesoscale Discussion | SPC | 4 hr |
| Jan 23, 3:00 PM CST | Wind Chill Advisory | LOT | 45 hr |
| Jan 26, 11:35 AM CST | River Flood Warning | LOT | 13 days |
| Jan 27, 3:01 AM CST | Winter Weather Advisory | LOT | 45 hr |
| Jan 28, 3:01 AM CST | Wind Chill Watch | LOT | 11 hr |
| Jan 28, 1:36 PM CST | Wind Chill Warning | LOT | 70 hr |
| Jan 28, 1:36 PM CST | Wind Chill Advisory | LOT | 28 hr |
| Jan 31, 3:17 AM CST | Winter Weather Advisory | LOT | 24 hr |
| Feb 2, 7:12 PM CST | Dense Fog Advisory | LOT | 6 hr |
| Feb 3, 10:11 AM CST | River Flood Advisory | LOT | 6 days |
| Feb 4, 2:05 PM CST | Winter Weather Advisory | LOT | 34 hr |
| Feb 5, 3:31 AM CST | Ice Storm Warning | LOT | 23 hr |
| Feb 5, 5:56 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 6, 2:55 AM CST | Winter Weather Advisory | LOT | 6 hr |
| Feb 6, 9:47 AM CST | Flash Flood Warning | LOT | 3 hr |
| Feb 7, 9:21 AM CST | Dense Fog Advisory | LOT | 5 hr |
| Feb 7, 12:14 PM CST | Wind Advisory | LOT | 15 hr |
| Feb 8, 10:29 AM CST | River Flood Advisory | LOT | 4 days |
| Feb 10, 2:43 PM CST | Winter Weather Advisory | LOT | 60 hr |
| Feb 11, 7:21 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Feb 11, 9:59 PM CST | Ice Storm Warning | LOT | 11 hr |
| Feb 12, 3:44 AM CST | Wind Advisory | LOT | 23 hr |
| Feb 12, 7:57 AM CST | Dense Fog Advisory | LOT | 2 hr |
| Feb 19, 3:35 AM CST | Winter Weather Advisory | LOT | 35 hr |
| Feb 22, 3:06 PM CST | High Wind Watch | LOT | 23 hr |
| Feb 23, 2:07 PM CST | High Wind Warning | LOT | 31 hr |
| Mar 3, 3:11 AM CST | Wind Chill Advisory | LOT | 32 hr |
| Mar 9, 2:29 PM CST | Wind Advisory | LOT | 16 hr |
| Mar 13, 2:42 PM CDT | Wind Advisory | LOT | 31 hr |
| Mar 14, 10:54 AM CDT | Mesoscale Discussion | SPC | 96 min |
| Mar 14, 11:32 AM CDT | Severe Thunderstorm Warning | LOT | 28 min |
| Mar 14, 12:24 PM CDT | Tornado Watch | SPC | 2 hr |
| Mar 14, 12:38 PM CDT | Special Weather Statement | LOT | 52 min |
| Apr 6, 5:03 AM CDT | Dense Fog Advisory | LOT | 4 hr |
| Apr 7, 3:14 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Apr 10, 2:52 PM CDT | Wind Advisory | LOT | 27 hr |
| Apr 12, 3:23 AM CDT | Wind Advisory | LOT | 17 hr |
| Apr 29, 11:09 AM CDT | River Flood Advisory | LOT | 24 hr |
| Apr 30, 10:44 AM CDT | River Flood Advisory | LOT | 17 hr |
| Apr 30, 10:44 AM CDT | River Flood Advisory | LOT | 23 hr |
| Apr 30, 10:54 AM CDT | River Flood Warning | LOT | 6 days |
| Apr 30, 2:22 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Apr 30, 2:44 PM CDT | Flash Flood Watch | LOT | 17 hr |
| May 1, 3:40 AM CDT | River Flood Warning | LOT | 49 hr |
| May 1, 9:27 AM CDT | River Flood Warning | LOT | 4 days |
| May 1, 2:14 PM CDT | Flash Flood Watch | LOT | 27 hr |
| May 7, 11:37 AM CDT | River Flood Advisory | LOT | 10 hr |
| May 9, 11:22 AM CDT | River Flood Advisory | LOT | 62 hr |
| May 16, 12:09 PM CDT | Mesoscale Discussion | SPC | 66 min |
| May 16, 12:17 PM CDT | Special Weather Statement | LOT | 43 min |
| May 16, 12:41 PM CDT | Severe Thunderstorm Warning | LOT | 64 min |
| May 16, 12:51 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| May 16, 7:14 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 16, 7:57 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| May 16, 11:12 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| May 22, 11:17 AM CDT | River Flood Advisory | LOT | 24 hr |
| May 22, 10:26 PM CDT | Tornado Watch | SPC | 8 hr |
| May 23, 1:23 AM CDT | Mesoscale Discussion | SPC | 97 min |
| May 24, 3:33 AM CDT | Flash Flood Watch | LOT | 22 hr |
| May 24, 11:31 AM CDT | River Flood Warning | LOT | 67 hr |
| May 24, 6:23 PM CDT | Tornado Watch | SPC | 4 hr |
| May 27, 11:38 AM CDT | River Flood Advisory | LOT | 5 days |
| May 27, 12:50 PM CDT | Mesoscale Discussion | SPC | 85 min |
| May 27, 1:22 PM CDT | Tornado Watch | SPC | 9 hr |
| May 27, 3:57 PM CDT | Mesoscale Discussion | SPC | 93 min |
| May 28, 4:01 AM CDT | Flash Flood Watch | LOT | 24 hr |
| May 28, 8:48 PM CDT | Severe Thunderstorm Watch | SPC | 4 hr |
| May 28, 9:28 PM CDT | Areal Flood Advisory | LOT | 6 hr |
| Jun 1, 5:21 PM CDT | Mesoscale Discussion | SPC | 54 min |
| Jun 5, 4:18 AM CDT | Areal Flood Advisory | LOT | 3 hr |
| Jun 23, 4:44 AM CDT | Special Weather Statement | LOT | 31 min |
| Jun 25, 1:10 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 27, 12:21 AM CDT | Special Weather Statement | LOT | 24 min |
| Jun 27, 12:29 AM CDT | Areal Flood Advisory | LOT | 2 hr |
| Jun 27, 12:52 AM CDT | Special Weather Statement | LOT | 38 min |
| Jun 27, 5:44 PM CDT | Special Weather Statement | LOT | 61 min |
| Jun 27, 6:17 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 27, 6:37 PM CDT | Special Weather Statement | LOT | 53 min |
| Jun 29, 5:03 PM CDT | Severe Thunderstorm Warning | LOT | 42 min |
| Jun 30, 11:43 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 30, 1:38 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 30, 1:46 PM CDT | Severe Thunderstorm Warning | LOT | 44 min |
| Jun 30, 2:02 PM CDT | Severe Thunderstorm Warning | LOT | 43 min |
| Jun 30, 2:28 PM CDT | Severe Thunderstorm Warning | LOT | 51 min |
| Jun 30, 2:31 PM CDT | Areal Flood Advisory | LOT | 4 hr |
| Jun 30, 9:18 PM CDT | River Flood Advisory | LOT | 13 hr |
| Jul 2, 2:31 PM CDT | Mesoscale Discussion | SPC | 89 min |
| Jul 6, 2:14 PM CDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 16, 2:30 PM CDT | Excessive Heat Watch | LOT | 24 hr |
| Jul 17, 2:14 PM CDT | Excessive Heat Warning | LOT | 3 days |
| Jul 18, 9:28 AM CDT | Special Weather Statement | LOT | 32 min |
| Jul 21, 12:51 PM CDT | Flash Flood Warning | LOT | 3 hr |
| Aug 14, 6:32 AM CDT | Dense Fog Advisory | LOT | 88 min |
| Aug 17, 8:00 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 18, 5:44 AM CDT | Mesoscale Discussion | SPC | 91 min |
| Aug 18, 6:06 AM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 18, 7:40 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 20, 6:18 AM CDT | Severe Thunderstorm Watch | SPC | 11 hr |
| Aug 20, 9:04 AM CDT | Mesoscale Discussion | SPC | 86 min |
| Aug 20, 10:16 AM CDT | Special Weather Statement | LOT | 59 min |
| Aug 20, 10:49 AM CDT | Special Weather Statement | LOT | 41 min |
| Sep 2, 4:47 AM CDT | Dense Fog Advisory | LOT | 3 hr |
| Sep 3, 9:00 AM CDT | Areal Flood Advisory | LOT | 2 hr |
| Sep 3, 3:54 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 12, 6:04 PM CDT | Mesoscale Discussion | SPC | 116 min |
| Sep 12, 6:40 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Sep 12, 10:58 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Sep 21, 3:35 AM CDT | Flash Flood Watch | LOT | 41 hr |
| Sep 27, 1:08 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Sep 27, 1:43 PM CDT | Flash Flood Watch | LOT | 16 hr |
| Sep 27, 3:15 PM CDT | Severe Thunderstorm Warning | LOT | 30 min |
| Sep 27, 4:04 PM CDT | Areal Flood Advisory | LOT | 3 hr |
| Sep 27, 5:31 PM CDT | Areal Flood Advisory | LOT | 116 min |
| Sep 27, 6:21 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Sep 27, 6:50 PM CDT | Areal Flood Advisory | LOT | 4 hr |
| Sep 27, 7:05 PM CDT | Areal Flood Advisory | LOT | 6 hr |
| Sep 27, 7:37 PM CDT | Flash Flood Warning | LOT | 6 hr |
| Sep 27, 8:00 PM CDT | Severe Thunderstorm Warning | LOT | 30 min |
| Sep 27, 9:02 PM CDT | Flash Flood Warning | LOT | 6 hr |
| Sep 27, 9:28 PM CDT | River Flood Warning | LOT | 66 hr |
| Sep 27, 9:39 PM CDT | River Flood Advisory | LOT | 33 hr |
| Sep 28, 1:33 AM CDT | Areal Flood Warning | LOT | 6 hr |
| Sep 28, 9:34 AM CDT | River Flood Advisory | LOT | 22 hr |
| Sep 28, 2:41 PM CDT | Flash Flood Watch | LOT | 16 hr |
| Oct 2, 9:15 PM CDT | Flash Flood Watch | LOT | 6 hr |
| Oct 3, 12:05 AM CDT | Areal Flood Advisory | LOT | 4 hr |
| Oct 11, 9:32 AM CDT | Areal Flood Advisory | LOT | 3 hr |
| Oct 13, 2:23 PM CDT | Frost Advisory | LOT | 18 hr |
| Oct 26, 10:04 AM CDT | Flood Watch | LOT | 16 hr |
| Oct 26, 7:10 PM CDT | Areal Flood Advisory | LOT | 96 min |
| Oct 26, 8:44 PM CDT | Areal Flood Warning | LOT | 12 hr |
| Oct 26, 9:57 PM CDT | River Flood Advisory | LOT | 37 hr |
| Oct 26, 10:30 PM CDT | River Flood Advisory | LOT | 12 hr |
| Oct 27, 10:29 AM CDT | River Flood Warning | LOT | 24 hr |
| Oct 29, 2:55 PM CDT | Winter Weather Advisory | LOT | 19 hr |
| Oct 30, 2:27 PM CDT | Winter Weather Advisory | LOT | 28 hr |
| Oct 30, 10:11 PM CDT | River Flood Advisory | LOT | 60 hr |
| Oct 31, 10:51 AM CDT | River Flood Advisory | LOT | 10 hr |
| Nov 10, 12:55 PM CST | Winter Weather Advisory | LOT | 32 hr |
| Nov 20, 4:42 AM CST | Dense Fog Advisory | LOT | 6 hr |
| Nov 25, 2:44 PM CST | High Wind Watch | LOT | 23 hr |
| Nov 26, 1:26 PM CST | High Wind Warning | LOT | 29 hr |
| Nov 27, 1:03 AM CST | Severe Thunderstorm Warning | LOT | 42 min |
| Dec 24, 1:36 AM CST | Freezing Fog Advisory | LOT | 8 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 archive20182020
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.