Alert archive / Wisconsin / Jefferson County
Weather alerts in Jefferson County, Wisconsin, 2020
94 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Jefferson County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 94
- Warnings
- 16
- Watches
- 10
- Advisories
- 31
- Busiest month
- July18 alerts
- Busiest day
- July 9, 20207 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Jefferson County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 10 | 6 | 40% | 2 | 50% | 15 min |
| Flash flood warnings | 0 | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Milwaukee, WI: tornado warnings | 13 | 3 | 77% | 5 | 80% | 16 min |
| NWS Milwaukee, WI: severe thunderstorm warnings | 92 | 54 | 41% | 214 | 78% | 26 min |
| NWS Milwaukee, WI: flash flood warnings | 11 | 8 | 27% | 21 | 86% | 104 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 9, 3:09 PM CST | Winter Storm Watch | MKX | 23 hr |
| Jan 10, 3:04 AM CST | Winter Storm Warning | MKX | 44 hr |
| Jan 10, 5:50 PM CST | Mesoscale Discussion | SPC | 6 hr |
| Jan 14, 2:02 PM CST | Winter Weather Advisory | MKX | 22 hr |
| Jan 16, 2:08 PM CST | Winter Weather Advisory | MKX | 52 hr |
| Jan 18, 3:10 PM CST | Wind Chill Advisory | MKX | 19 hr |
| Jan 19, 10:26 AM CST | River Flood Warning | MKX | 35 hr |
| Jan 21, 3:35 PM CST | River Flood Warning | MKX | 4 hr |
| Jan 24, 3:12 AM CST | Winter Weather Advisory | MKX | 33 hr |
| Feb 8, 3:27 AM CST | Winter Weather Advisory | MKX | 40 hr |
| Feb 9, 10:56 AM CST | Mesoscale Discussion | SPC | 5 hr |
| Feb 13, 2:29 PM CST | Wind Chill Advisory | MKX | 20 hr |
| Feb 16, 2:55 PM CST | Winter Weather Advisory | MKX | 33 hr |
| Feb 23, 2:03 PM CST | Winter Storm Watch | MKX | 24 hr |
| Mar 5, 5:41 PM CST | Wind Advisory | MKX | 12 hr |
| Apr 7, 3:06 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Apr 7, 3:55 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Apr 8, 12:30 AM CDT | Dense Fog Advisory | MKX | 10 hr |
| Apr 12, 2:34 PM CDT | Wind Advisory | MKX | 25 hr |
| Apr 20, 6:15 PM CDT | Special Weather Statement | MKX | 90 min |
| Apr 20, 6:23 PM CDT | Special Weather Statement | MKX | 37 min |
| Apr 20, 8:36 PM CDT | Special Weather Statement | MKX | 54 min |
| Apr 27, 11:19 PM CDT | Dense Fog Advisory | MKX | 11 hr |
| Apr 29, 2:47 AM CDT | Dense Fog Advisory | MKX | 7 hr |
| May 7, 9:25 AM CDT | Freeze Watch | MKX | 18 hr |
| May 8, 3:53 AM CDT | Freeze Warning | MKX | 28 hr |
| May 10, 3:32 PM CDT | Frost Advisory | MKX | 16 hr |
| May 11, 2:52 PM CDT | Frost Advisory | MKX | 17 hr |
| May 12, 2:29 PM CDT | Frost Advisory | MKX | 18 hr |
| May 15, 4:06 AM CDT | Dense Fog Advisory | MKX | 5 hr |
| May 23, 12:33 PM CDT | Tornado Watch | SPC | 8 hr |
| May 23, 2:51 PM CDT | Mesoscale Discussion | SPC | 84 min |
| Jun 2, 5:32 PM CDT | Mesoscale Discussion | SPC | 118 min |
| Jun 2, 5:48 PM CDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Jun 2, 8:47 PM CDT | Special Weather Statement | MKX | 73 min |
| Jun 2, 9:28 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 5, 12:26 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Jun 9, 2:12 PM CDT | Wind Advisory | MKX | 14 hr |
| Jun 11, 3:26 PM CDT | Mesoscale Discussion | SPC | 94 min |
| Jun 11, 4:38 PM CDT | Severe Thunderstorm Warning | MKX | 37 min |
| Jun 26, 12:38 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 26, 1:38 PM CDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 26, 3:39 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 29, 1:28 PM CDT | Mesoscale Discussion | SPC | 92 min |
| Jun 29, 2:11 PM CDT | Severe Thunderstorm Warning | MKX | 64 min |
| Jun 29, 2:43 PM CDT | Special Weather Statement | MKX | 47 min |
| Jun 29, 3:22 PM CDT | Special Weather Statement | MKX | 53 min |
| Jul 7, 1:23 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 7, 5:29 PM CDT | Severe Thunderstorm Warning | MKX | 31 min |
| Jul 9, 12:51 PM CDT | Special Weather Statement | MKX | 24 min |
| Jul 9, 1:57 PM CDT | Special Weather Statement | MKX | 33 min |
| Jul 9, 2:51 PM CDT | Mesoscale Discussion | SPC | 114 min |
| Jul 9, 3:39 PM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 9, 5:39 PM CDT | Mesoscale Discussion | SPC | 96 min |
| Jul 9, 6:31 PM CDT | Severe Thunderstorm Warning | MKX | 44 min |
| Jul 9, 6:59 PM CDT | Severe Thunderstorm Warning | MKX | 46 min |
| Jul 15, 3:09 PM CDT | Special Weather Statement | MKX | 36 min |
| Jul 17, 2:54 AM CDT | Heat Advisory | MKX | 41 hr |
| Jul 18, 11:00 AM CDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 19, 3:44 AM CDT | Mesoscale Discussion | SPC | 91 min |
| Jul 19, 5:17 AM CDT | Special Weather Statement | MKX | 28 min |
| Jul 26, 2:37 AM CDT | Heat Advisory | MKX | 16 hr |
| Jul 26, 5:33 PM CDT | Mesoscale Discussion | SPC | 87 min |
| Jul 26, 5:40 PM CDT | Special Weather Statement | MKX | 35 min |
| Jul 26, 5:45 PM CDT | Areal Flood Advisory | MKX | 2 hr |
| Aug 9, 1:30 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 9, 4:45 PM CDT | Special Weather Statement | MKX | 60 min |
| Aug 9, 5:00 PM CDT | Severe Thunderstorm Warning | MKX | 45 min |
| Aug 10, 10:42 AM CDT | Mesoscale Discussion | SPC | 93 min |
| Aug 10, 11:26 AM CDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 10, 4:34 PM CDT | Areal Flood Advisory | MKX | 3 hr |
| Aug 24, 10:55 PM CDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 24, 11:23 PM CDT | Severe Thunderstorm Warning | MKX | 39 min |
| Aug 25, 12:29 AM CDT | Severe Thunderstorm Warning | MKX | 46 min |
| Aug 25, 1:45 AM CDT | Severe Thunderstorm Warning | MKX | 46 min |
| Aug 25, 2:48 AM CDT | Special Weather Statement | MKX | 57 min |
| Aug 27, 8:55 PM CDT | Special Weather Statement | MKX | 65 min |
| Aug 28, 6:58 PM CDT | Special Weather Statement | MKX | 32 min |
| Oct 1, 3:29 AM CDT | Frost Advisory | MKX | 30 hr |
| Oct 4, 9:27 AM CDT | Frost Advisory | MKX | 23 hr |
| Oct 15, 2:56 AM CDT | Freeze Warning | MKX | 29 hr |
| Oct 16, 2:21 PM CDT | Wind Advisory | MKX | 29 hr |
| Nov 1, 3:09 AM CST | Wind Advisory | MKX | 13 hr |
| Nov 10, 3:09 AM CST | Wind Advisory | MKX | 25 hr |
| Nov 10, 1:28 PM CST | Mesoscale Discussion | SPC | 92 min |
| Nov 10, 2:05 PM CST | Tornado Watch | SPC | 6 hr |
| Nov 10, 4:17 PM CST | Severe Thunderstorm Warning | MKX | 44 min |
| Nov 14, 1:08 PM CST | Wind Advisory | MKX | 32 hr |
| Nov 23, 1:44 PM CST | Winter Weather Advisory | MKX | 22 hr |
| Nov 24, 8:22 PM CST | Dense Fog Advisory | MKX | 14 hr |
| Dec 11, 3:21 AM CST | Winter Weather Advisory | MKX | 35 hr |
| Dec 28, 1:49 PM CST | Winter Storm Warning | MKX | 40 hr |
| Dec 28, 1:49 PM CST | Winter Weather Advisory | MKX | 43 hr |
| Dec 29, 3:52 PM CST | Mesoscale Discussion | SPC | 4 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 |
| Severe Thunderstorm Watch | 5 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 22 |
| Special Weather Statement | 15 |
| Flooding | |
| River Flood Warning | 2 |
| Areal Flood Advisory | 2 |
| Winter | |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 8 |
| Heat | |
| Heat Advisory | 2 |
| Cold | |
| Freeze Warning | 2 |
| Freeze Watch | 1 |
| Frost Advisory | 5 |
| Wind Chill Advisory | 2 |
| Wind and dust | |
| Wind Advisory | 7 |
| Fog and smoke | |
| Dense Fog Advisory | 5 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
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.