Tornadoes · United States · Florida · 1998
F0 tornado, Key West, Florida, June 18, 1998
This F0 tornado ran 0.3 miles across Monroe County on June 18, 1998, touching down at 3:10 PM EDT and reaching 30 yards wide. It killed nobody, and did $10,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mph
Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 mph
Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.
Unrated
The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.
The record
- Rating
- F0
- Date
- June 18, 1998
- Touchdown
- 3:10 PM EDT (19:10 UTC)
- Path length
- 0.3 miles (0.5 km)
- Path width
- 30 yards (27 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $10,000
- County
- Monroe County
- Touchdown point
- 24.550, -81.770
- Lift-off point
- 24.550, -81.770
- Record number
- 492
What the Weather Service recorded
Funnel cloud moved onshore and lowered resulting in a F0 tornado. The tornado moved along 10th ST between North Roosevelt Ave and Flagler Ave. Tree were toppled...roofs and awnings were damaged...powerlines were downed and a shack was tipped over.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.
The air that afternoon
The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.
Key West, FL (KEYW), 00:00Z
4.8 hours after it, 5 km from the path. June 19, 1998.
- Mixed-layer CAPE
- 3272 J/kg
- Mixed-layer CIN
- -4 J/kg
- Surface CAPE
- 3378 J/kg
- Mixed-layer LCL
- 809 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 70 m²/s²
- 0-3 km storm-relative helicity
- 82 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 6.5 K/km
The radar
The Key West radar (KBYX), 9 km away, was scanning. The volume nearest the touchdown began at 19:11 UTC.
Open the radar archive at this moment, over the track
Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.
This ground now
The live radar over the trackEvery 1998 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are
The other tornadoes of June 18, 1998
21 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| June 18 | 2:04 PM CDT | F1 | Warren, IA | 13.0 | 40 | $10,000 | ||
| June 18 | 3:10 PM CDT | F0 | Burleigh, ND | 0.2 | 30 | |||
| June 18 | 3:30 PM CDT | F2 | Buchanan, IA | 20.0 | 30 | $800,000 | ||
| June 18 | 3:40 PM CDT | F1 | Buchanan, IA | 15.0 | 30 | $40,000 | ||
| June 18 | 3:55 PM CDT | F1 | Redwood, MN | 2.5 | 30 | |||
| June 18 | 4:00 PM CDT | F0 | Renville, MN | 0.1 | 30 | |||
| June 18 | 4:07 PM CDT | F0 | Redwood, MN | 0.1 | 30 | |||
| June 18 | 4:18 PM CDT | F1 | Renville, MN | 0.2 | 50 | $1.0 million | ||
| June 18 | 4:40 PM CDT | F0 | Linn, IA | 0.1 | 30 | |||
| June 18 | 4:41 PM CDT | F0 | Cedar, IA | 0.1 | 30 | |||
| June 18 | 5:00 PM CDT | F1 | Louisa, IA | 1.0 | 100 | 1 | $180,000 | |
| June 18 | 5:07 PM CDT | F1 | Vernon, WI | 1.5 | 120 | $100,000 | ||
| June 18 | 5:10 PM CDT | F0 | Grant, WI | 0.1 | 40 | 1 | $200,000 | |
| June 18 | 5:10 PM CDT | F0 | Louisa, IA | 0.1 | 30 | $2,000 | ||
| June 18 | 5:10 PM CDT | F2 | Mercer, IL | 6.0 | 880 | $110,000 | ||
| June 18 | 5:30 PM CDT | F0 | Warren, IL | 0.1 | 30 | |||
| June 18 | 6:30 PM CDT | F0 | Bureau, IL | 0.1 | 30 | |||
| June 18 | 6:40 PM CDT | F0 | Wagoner, OK | 0.5 | 50 | $10,000 | ||
| June 18 | 6:55 PM CDT | F0 | Lee, IL | 0.5 | 30 | |||
| June 18 | 7:08 PM CDT | F0 | Traill, ND | 0.2 | 30 | |||
| June 18 | 9:57 PM CDT | F0 | Montague, TX | 0.1 | 30 |
What this means
Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.