Alert archive / Tennessee / Johnson County
Weather alerts in Johnson County, Tennessee, 2026
107 weather alerts in 2026, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Johnson County and its neighbors
Each county as a circle sized by its count in 2026. Tap one for its archive.
- Alerts
- 107
- Warnings
- 18
- Watches
- 16
- Advisories
- 36
- Busiest month
- August33 alerts
- Busiest day
- August 17, 202612 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
0 of 1 tornado warnings covering Johnson County in 2026 had a tornado report inside them.
Johnson County, 2026
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 1 | 0 | 100% | 0 | ||
| Severe thunderstorm warnings | 10 | 9 | 10% | 2 | 50% | 5 min |
| Flash flood warnings | 2 | 1 | 50% | 0 |
Each office's whole area, 2026
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Morristown, TN: tornado warnings | 10 | 1 | 90% | 3 | 33% | 3 min |
| NWS Morristown, TN: severe thunderstorm warnings | 182 | 146 | 20% | 226 | 89% | 22 min |
| NWS Morristown, TN: flash flood warnings | 81 | 55 | 32% | 128 | 84% | 70 min |
An office's figures cover every county it serves, including across state lines.
The year is still running; reports filed late and damage surveys can still change these figures.
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, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 10, 1:22 PM EST | Wind Advisory | MRX | 30 hr |
| Jan 13, 11:29 AM EST | Winter Weather Advisory | MRX | 48 hr |
| Jan 21, 12:27 PM EST | Winter Storm Watch | MRX | 45 hr |
| Jan 23, 9:54 AM EST | Winter Storm Warning | MRX | 49 hr |
| Jan 23, 9:54 AM EST | Winter Weather Advisory | MRX | 47 hr |
| Jan 24, 6:45 PM EST | Mesoscale Discussion | SPC | 5 hr |
| Jan 24, 11:49 PM EST | Cold Weather Advisory | MRX | 34 hr |
| Jan 25, 12:01 PM EST | Cold Weather Advisory | MRX | 48 hr |
| Jan 25, 12:01 PM EST | Extreme Cold Watch | MRX | 14 hr |
| Jan 29, 2:50 AM EST | Winter Storm Watch | MRX | 10 hr |
| Jan 29, 12:50 PM EST | Winter Storm Warning | MRX | 57 hr |
| Jan 29, 1:00 PM EST | Extreme Cold Watch | MRX | 23 hr |
| Jan 30, 12:20 PM EST | Extreme Cold Warning | MRX | 48 hr |
| Feb 2, 12:39 AM EST | Cold Weather Advisory | MRX | 8 hr |
| Feb 4, 4:01 AM EST | Dense Fog Advisory | MRX | 8 hr |
| Feb 5, 12:30 PM EST | Wind Advisory | MRX | 55 hr |
| Feb 5, 12:30 PM EST | Winter Weather Advisory | MRX | 43 hr |
| Feb 6, 12:34 PM EST | Cold Weather Advisory | MRX | 21 hr |
| Feb 14, 12:06 PM EST | Wind Advisory | MRX | 26 hr |
| Feb 19, 2:29 AM EST | Wind Advisory | MRX | 35 hr |
| Feb 21, 1:31 PM EST | Winter Weather Advisory | MRX | 58 hr |
| Mar 9, 3:05 AM EDT | Dense Fog Advisory | MRX | 7 hr |
| Mar 14, 2:07 AM EDT | High Wind Watch | MRX | 12 hr |
| Mar 14, 1:44 PM EDT | High Wind Warning | MRX | 42 hr |
| Mar 16, 12:41 AM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Mar 16, 12:51 AM EDT | Winter Weather Advisory | MRX | 38 hr |
| Mar 16, 4:21 AM EDT | Mesoscale Discussion | SPC | 114 min |
| Apr 26, 12:52 AM EDT | Dense Fog Advisory | MRX | 9 hr |
| Apr 27, 1:20 PM EDT | Wind Advisory | MRX | 17 hr |
| Apr 29, 2:45 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 2, 12:42 PM EDT | Freeze Warning | MRX | 20 hr |
| May 24, 12:57 PM EDT | Flood Watch | MRX | 13 hr |
| Jun 7, 2:09 PM EDT | Flood Watch | MRX | 31 hr |
| Jun 12, 2:36 PM EDT | Mesoscale Discussion | SPC | 24 min |
| Jun 18, 11:39 AM EDT | Special Weather Statement | MRX | 66 min |
| Jun 18, 1:43 PM EDT | Mesoscale Discussion | SPC | 62 min |
| Jun 18, 2:38 PM EDT | Flood Watch | MRX | 11 hr |
| Jun 18, 6:51 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Jun 22, 1:25 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 27, 9:44 AM EDT | Flood Watch | MRX | 28 hr |
| Jun 27, 2:43 PM EDT | Special Weather Statement | MRX | 47 min |
| Jun 29, 1:34 PM EDT | Heat Advisory | MRX | 5 days |
| Jul 4, 1:38 PM EDT | Special Weather Statement | MRX | 52 min |
| Jul 4, 1:49 PM EDT | Special Weather Statement | MRX | 26 min |
| Jul 4, 10:35 PM EDT | Severe Thunderstorm Warning | MRX | 55 min |
| Jul 4, 11:02 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Jul 4, 11:05 PM EDT | Severe Thunderstorm Warning | MRX | 55 min |
| Jul 4, 11:07 PM EDT | Severe Thunderstorm Warning | MRX | 53 min |
| Jul 6, 5:03 PM EDT | Areal Flood Advisory | MRX | 117 min |
| Jul 9, 11:44 AM EDT | Flood Watch | MRX | 4 days |
| Jul 11, 8:38 AM EDT | Special Weather Statement | MRX | 37 min |
| Jul 18, 1:56 PM EDT | Mesoscale Discussion | SPC | 64 min |
| Jul 19, 3:11 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 20, 1:20 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Jul 21, 1:45 PM EDT | Flood Watch | MRX | 54 hr |
| Jul 28, 12:33 PM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 28, 1:14 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 28, 3:39 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 28, 4:16 PM EDT | Tornado Warning | MRX | 44 min |
| Jul 28, 4:30 PM EDT | Severe Thunderstorm Warning | MRX | 45 min |
| Jul 28, 4:55 PM EDT | Severe Thunderstorm Warning | MRX | 20 min |
| Aug 2, 1:09 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 2, 10:56 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Aug 4, 4:44 PM EDT | Areal Flood Advisory | MRX | 113 min |
| Aug 11, 2:04 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Aug 11, 3:40 PM EDT | Special Weather Statement | MRX | 50 min |
| Aug 11, 4:07 PM EDT | Severe Thunderstorm Warning | MRX | 38 min |
| Aug 11, 4:17 PM EDT | Areal Flood Advisory | MRX | 118 min |
| Aug 11, 4:39 PM EDT | Areal Flood Advisory | MRX | 2 hr |
| Aug 11, 4:42 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 5:53 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 11, 7:06 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 11, 7:50 PM EDT | Severe Thunderstorm Warning | MRX | 55 min |
| Aug 11, 8:24 PM EDT | Severe Thunderstorm Warning | MRX | 47 min |
| Aug 12, 2:38 AM EDT | Flood Watch | MRX | 29 hr |
| Aug 12, 11:41 PM EDT | Special Weather Statement | MRX | 49 min |
| Aug 14, 6:57 PM EDT | Special Weather Statement | MRX | 48 min |
| Aug 14, 7:07 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Aug 14, 8:03 PM EDT | Flash Flood Warning | MRX | 3 hr |
| Aug 15, 1:25 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 17, 1:49 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Aug 17, 2:35 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Aug 17, 3:26 PM EDT | Severe Thunderstorm Warning | MRX | 49 min |
| Aug 17, 3:48 PM EDT | Special Weather Statement | MRX | 42 min |
| Aug 17, 4:21 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Aug 17, 4:31 PM EDT | Special Weather Statement | MRX | 44 min |
| Aug 17, 5:12 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Aug 17, 5:32 PM EDT | Flash Flood Warning | MRX | 3 hr |
| Aug 17, 5:36 PM EDT | Special Weather Statement | MRX | 39 min |
| Aug 17, 5:49 PM EDT | Mesoscale Discussion | SPC | 116 min |
| Aug 17, 5:56 PM EDT | Severe Thunderstorm Warning | MRX | 34 min |
| Aug 17, 7:38 PM EDT | Special Weather Statement | MRX | 52 min |
| Aug 17, 8:21 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Aug 17, 8:21 PM EDT | Areal Flood Advisory | MRX | 2 hr |
| Sep 5, 10:40 AM EDT | Mesoscale Discussion | SPC | 95 min |
| Sep 5, 11:56 AM EDT | Special Weather Statement | MRX | 49 min |
| Sep 6, 7:26 AM EDT | Special Weather Statement | MRX | 64 min |
| Sep 6, 8:00 AM EDT | Areal Flood Advisory | MRX | 2 hr |
| Sep 6, 12:13 PM EDT | Special Weather Statement | MRX | 62 min |
| Sep 6, 12:36 PM EDT | Areal Flood Advisory | MRX | 3 hr |
| Sep 18, 4:49 PM EDT | Areal Flood Advisory | MRX | 116 min |
| Sep 21, 6:34 PM EDT | Special Weather Statement | MRX | 26 min |
| Sep 21, 6:55 PM EDT | Special Weather Statement | MRX | 35 min |
| Sep 21, 7:08 PM EDT | Areal Flood Advisory | MRX | 2 hr |
| Sep 21, 7:11 PM EDT | Areal Flood Advisory | MRX | 2 hr |
| Sep 21, 7:17 PM EDT | Special Weather Statement | MRX | 43 min |
| Sep 21, 7:43 PM EDT | Areal Flood Advisory | MRX | 2 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 |
| Tornado Warning | 1 |
| Severe Thunderstorm Watch | 4 |
| Mesoscale Discussion | 19 |
| Special Weather Statement | 18 |
| Flooding | |
| Flash Flood Warning | 2 |
| Flood Watch | 7 |
| Areal Flood Advisory | 18 |
| Winter | |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 2 |
| Winter Weather Advisory | 5 |
| Heat | |
| Heat Advisory | 1 |
| Cold | |
| Extreme Cold Warning | 1 |
| Freeze Warning | 1 |
| Extreme Cold Watch | 2 |
| Cold Weather Advisory | 4 |
| Wind and dust | |
| High Wind Warning | 1 |
| High Wind Watch | 1 |
| Wind Advisory | 5 |
| Fog and smoke | |
| Dense Fog Advisory | 3 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive2025
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.