Weather alerts in Tennessee, 2012
2,559 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2012. Tap one for its archive.
- Alerts
- 2,559
- Warnings
- 1,157
- Watches
- 83
- Advisories
- 382
- Busiest month
- July533 alerts
- Busiest day
- March 2, 2012131 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
25 of 163 tornado warnings covering Tennessee in 2012 had a tornado report inside them; 28 of 42 tornado reports fell inside a warning, on average 19 minutes after it went out.
Tennessee, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 163 | 25 | 85% | 42 | 67% | 19 min |
| Severe thunderstorm warnings | 890 | 470 | 47% | 1,027 | 70% | 20 min |
| Flash flood warnings | 72 | 23 | 68% | 50 | 72% | 52 min |
Each office's whole area, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Huntsville, AL: tornado warnings | 34 | 7 | 79% | 26 | 62% | 19 min |
| NWS Huntsville, AL: severe thunderstorm warnings | 214 | 77 | 64% | 313 | 56% | 17 min |
| NWS Huntsville, AL: flash flood warnings | 40 | 13 | 68% | 64 | 67% | 70 min |
| NWS Atlanta, GA: tornado warnings | 28 | 9 | 68% | 16 | 75% | 22 min |
| NWS Atlanta, GA: severe thunderstorm warnings | 350 | 215 | 39% | 421 | 75% | 15 min |
| NWS Atlanta, GA: flash flood warnings | 23 | 9 | 61% | 16 | 81% | 50 min |
| NWS Memphis, TN: tornado warnings | 76 | 11 | 86% | 22 | 68% | 14 min |
| NWS Memphis, TN: severe thunderstorm warnings | 482 | 201 | 58% | 468 | 72% | 22 min |
| NWS Memphis, TN: flash flood warnings | 64 | 16 | 75% | 39 | 82% | 48 min |
| NWS Nashville, TN: tornado warnings | 65 | 7 | 89% | 19 | 74% | 17 min |
| NWS Nashville, TN: severe thunderstorm warnings | 381 | 193 | 49% | 531 | 63% | 18 min |
| NWS Nashville, TN: flash flood warnings | 22 | 8 | 64% | 18 | 61% | 73 min |
| NWS Morristown, TN: tornado warnings | 81 | 12 | 85% | 23 | 83% | 19 min |
| NWS Morristown, TN: severe thunderstorm warnings | 311 | 198 | 36% | 358 | 78% | 22 min |
| NWS Morristown, TN: flash flood warnings | 16 | 8 | 50% | 14 | 93% | 63 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
2,559 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Davidson County203
- Shelby County196
- Wilson County191
- Williamson County189
- Sumner County183
- McNairy County180
- Blount County179
- Fayette County179
- Dickson County177
- Robertson County177
- Franklin County177
- Rutherford County176
- Cheatham County175
- Hardeman County175
- Montgomery County173
- Humphreys County171
- Lincoln County170
- Stewart County163
- Hardin County163
- Maury County162
- Lauderdale County162
- Houston County161
- Hickman County160
- Madison County159
- Tipton County159
- Trousdale County158
- Sevier County157
- Haywood County155
- Monroe County155
- Carroll County154
- Lawrence County153
- Benton County151
- Giles County147
- Wayne County146
- Chester County146
- Hamilton County145
- Moore County144
- Henderson County144
- Overton County143
- Greene County140
55 more counties
- Coffee County139
- Putnam County139
- Smith County139
- Dyer County139
- Macon County138
- Weakley County138
- Marshall County137
- Jackson County135
- Decatur County135
- Gibson County135
- Cocke County134
- Obion County134
- Crockett County133
- Bradley County133
- McMinn County133
- Clay County132
- Henry County132
- Lake County132
- Polk County132
- Perry County131
- Cumberland County130
- Bedford County129
- White County129
- Carter County126
- Cannon County125
- Knox County124
- Rhea County123
- Fentress County122
- Lewis County122
- Pickett County122
- Warren County122
- Unicoi County119
- DeKalb County118
- Bledsoe County118
- Sequatchie County118
- Johnson County117
- Campbell County117
- Marion County117
- Sullivan County115
- Meigs County114
- Grundy County113
- Scott County113
- Van Buren County112
- Hawkins County112
- Roane County107
- Washington County106
- Claiborne County105
- Loudon County105
- Morgan County104
- Anderson County103
- Hancock County97
- Jefferson County94
- Union County94
- Grainger County93
- Hamblen County79
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20112013
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.