Tornadoes · United States · Florida · 2024

EF0 tornado, Big Coppit Is, Florida, March 19, 2024

This EF0 tornado ran 0.3 miles across Monroe County on March 19, 2024, touching down at 4:01 AM EDT and reaching 20 yards wide. It killed nobody, and did $2,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

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

  2. EF186 to 110 mph

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

  3. EF2111 to 135 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. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

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

  6. EF5over 200 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
EF0
Date
March 19, 2024
Touchdown
4:01 AM EDT (08:01 UTC)
Lifted
4:02 AM EDT (08:02 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.4 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
Property damage
$2,000
County
Monroe County
Touchdown point
24.676, -81.395
Lift-off point
24.674, -81.391
Record number
2403190201-01

What the Weather Service recorded

A tornado was observed at Little Torch Key as rapid development of showers and thunderstorms occurred directly over the Lower and Middle Florida Keys. A cold front was approaching from the north, with the thunderstorms development over a pre-existing convergence boundary just as northerly surface winds were spreading over the Florida Keys.

A brief tornado was determined to have passed from State Road 4A through Diane Avenue and Linda Street on the northern portion of Little Torch Key. The narrow path was marked by two downed buttonwood trees, broken small and medium-sized tree branches, a destroyed plastic storage shed, and three destroyed breakaway shade canopies. No structural damage was observed. Estimated maximum winds were 65 to 70 mph.

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.

Issued (UTC)ExpiredProductOffice
10:19 UTC12:26 UTCWind AdvisoryKEY

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

8.0 hours before the tornado, 35 km from the path. March 19, 2024.

Skew-T log-pSkew-T log-p diagram, Key West, FL at 00:00Z on 2024-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1142 joules per kilogram, CIN -36, lifted condensation level 1154 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2024-03-19The 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 66 square meters per square second, 0 to 6 km bulk shear 37 knots.1939587897Sfc1 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
1142 J/kg
Mixed-layer CIN
-36 J/kg
Surface CAPE
2274 J/kg
Mixed-layer LCL
1154 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.0
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

Key West, FL (KEYW), 12:00Z

4.0 hours after it, 35 km from the path. March 19, 2024.

Skew-T log-pSkew-T log-p diagram, Key West, FL at 12:00Z on 2024-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 24 joules per kilogram, CIN -373, lifted condensation level 1340 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°0°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 2024-03-19The 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 -41 square meters per square second, 0 to 6 km bulk shear 60 knots.1939587897117136Sfc1 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
24 J/kg
Mixed-layer CIN
-373 J/kg
Surface CAPE
110 J/kg
Mixed-layer LCL
1340 m above ground
0-6 km bulk shear
60 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
-41 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The surface observations

Key West Nas (NQX), 32 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
06:43 UTC180° 7 kt1012.9
06:53 UTC190° 14 kt191013.2
07:10 UTC7975200° 15 kt1013.2
07:34 UTC7876260° 12 kt161013.9+RA BR
07:38 UTC7776280° 4 kt161013.5+RA BR
07:46 UTC767520° 7 kt1013.2RA BR
07:49 UTC75.275.2360° 5 kt1013.5RA BR
07:58 UTC7675360° 17 kt221014.2+RA BR
08:06 UTC7574 1014.6
08:22 UTC360° 19 kt251013.9+RA
08:34 UTC7573350° 18 kt271013.9-RA BR
08:43 UTC7674360° 22 kt281014.2-RA
08:53 UTC7674360° 18 kt271014.2
09:02 UTC7674350° 21 kt271014.2
09:50 UTC75.269.8350° 25 kt401014.9
09:53 UTC7570350° 29 kt401014.9
09:59 UTC7570350° 23 kt401014.6

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Key West radar (KBYX), 33 km away, was scanning. The volume nearest the touchdown began at 08:01 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 2024 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

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.