Tornadoes · United States · Florida · 1999

F0 tornado, Key West, Florida, May 30, 1999

This F0 tornado ran 0.0 miles across Monroe County on May 30, 1999, touching down at 12:15 PM EDT. It killed nobody.

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.

  1. F040 to 72 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. 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.

  4. 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.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. 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.

  7. 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
May 30, 1999
Touchdown
12:15 PM EDT (16:15 UTC)
Path length
0.0 miles (0.0 km)
Path width
0 yards (0 m)
Deaths
0
Injuries
0
County
Monroe County
Touchdown point
24.550, -81.770
Lift-off point
24.550, -81.770
Record number
240

What the Weather Service recorded

On May 30th at 12:15 pm EDT, a waterspout moved onshore along the north end of Duval Street inKey West as a tornado and dissipated quickly after moving onshore. There was no damage or injuries reported with this event.

On May 30th at 1215 pm EDT, a waterspout moved onshore along the north side of Key West as a tornado but dissipated quickly after hitting land. No damage or injuries were reported with this event.

Waterspout dissipated quickly after moving onshore

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 forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 12:52 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

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), 12:00Z

4.3 hours before the tornado, 5 km from the path. May 30, 1999.

Skew-T log-pSkew-T log-p diagram, Key West, FL at 12:00Z on 1999-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2133 joules per kilogram, CIN 0, lifted condensation level 733 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Key West, FL at 12:00Z on 1999-05-30The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -5 square meters per square second, 0 to 6 km bulk shear 22 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
2133 J/kg
Mixed-layer CIN
0 J/kg
Surface CAPE
2978 J/kg
Mixed-layer LCL
733 m above ground
0-6 km bulk shear
22 kt
0-1 km bulk shear
2 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.3 K/km

Open this sounding in Storm Lab

Key West, FL (KEYW), 00:00Z

7.7 hours after it, 5 km from the path. May 31, 1999.

Skew-T log-pSkew-T log-p diagram, Key West, FL at 00:00Z on 1999-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 929 joules per kilogram, CIN -23, lifted condensation level 1016 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Key West, FL at 00:00Z on 1999-05-31The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 2 square meters per square second, 0 to 6 km bulk shear 24 knots.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
929 J/kg
Mixed-layer CIN
-23 J/kg
Surface CAPE
1783 J/kg
Mixed-layer LCL
1016 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
2 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.0
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1999 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

The other tornadoes of May 30, 1999

11 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 307:30 AM EDTF0Brevard, FL0.130$40,000
May 3012:15 PM EDTF0Monroe, FL0.00
May 3012:09 PM CDTF0Pearl River, MS0.530
May 301:54 PM CDTF0Arkansas, AR0.10
May 301:25 PM MDTF0Laramie, WY0.250$2,000
May 306:15 PM CDTF0Dixon, NE0.150
May 306:30 PM CDTF1Fort Bend, TX1.0100$100,000
May 307:13 PM CDTF1Dawson, NE5.0100$50,000
May 308:15 PM CDTF0Jefferson Parish, LA0.20$1,000
May 309:50 PM CDTF1Lavaca, TX0.230$10,000
May 3010:15 PM CDTF1Lavaca, TX0.120$50,000

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.