Tornadoes · United States · Florida · 2004

F0 tornado, Polk County, Florida, August 13, 2004

This F0 tornado ran 1.0 miles across Polk County on August 13, 2004, touching down at 1:55 PM EDT and reaching 30 yards wide. 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
August 13, 2004
Touchdown
1:55 PM EDT (17:55 UTC)
Path length
1.0 miles (1.6 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Polk County
Touchdown point
28.170, -81.600
Lift-off point
28.180, -81.600
Record number
1520

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
16:47 UTC17:15 UTCTornado WarningTBW
17:15 UTC17:45 UTCTornado WarningTBW
17:50 UTC18:15 UTCSevere Thunderstorm WarningTBW
17:57 UTC18:30 UTCTornado WarningTBW
20:01 UTC20:30 UTCTornado WarningTBW

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:27 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.

Tampa Bay, FL (KTBW), 12:00Z

5.9 hours before the tornado, 95 km from the path. August 13, 2004.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 12:00Z on 2004-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -62881, lifted condensation level 1607 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Tampa Bay, FL at 12:00Z on 2004-08-13The 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 -160 square meters per square second, 0 to 6 km bulk shear 12 knots.1939Sfc1 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
0 J/kg
Mixed-layer CIN
-62881 J/kg
Surface CAPE
315 J/kg
Mixed-layer LCL
1607 m above ground
0-6 km bulk shear
12 kt
0-1 km bulk shear
31 kt
0-1 km storm-relative helicity
-160 m²/s²
0-3 km storm-relative helicity
-117 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Tampa Bay, FL (KTBW), 00:00Z

6.1 hours after it, 95 km from the path. August 14, 2004.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 00:00Z on 2004-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 110 joules per kilogram, CIN -61, lifted condensation level 504 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, Tampa Bay, FL at 00:00Z on 2004-08-14The 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 35 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
110 J/kg
Mixed-layer CIN
-61 J/kg
Surface CAPE
76 J/kg
Mixed-layer LCL
504 m above ground
0-6 km bulk shear
35 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
-66 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

The surface observations

Winter Haven (Asos) (GIF), 20 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
16:53 UTC837190° 7 kt1015.6
17:53 UTC757370° 4 kt1015.6-TSRA
18:53 UTC727040° 9 kt1013.9-TSRA
19:53 UTC737050° 12 kt1012.5-RA

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

The radar

The Melbourne radar (KMLB), 93 km away, was scanning. The volume nearest the touchdown began at 17:52 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 2004 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

The other tornadoes of August 13, 2004

17 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 133:55 AM EDTF2Pender, NC5.0500329$1.3 million
August 135:11 AM EDTF0Onslow, NC0.130$30,000
August 135:53 AM EDTF1Carteret, NC0.3203$280,000
August 137:00 AM EDTF1Beaufort, NC2.030$100,000
August 1311:04 AM EDTF2Hendry, FL42.0100$50,000
August 1312:05 PM EDTF0Hardee, FL2.030
August 131:00 PM EDTF0Polk, FL1.030
August 133:10 PM EDTF0DeSoto, FL1.030$10,000
August 133:40 PM EDTF0Lee, FL0.250
August 133:55 PM EDTF1Lee, FL1.8100
August 134:15 PM EDTF1Charlotte, FL2.550
August 134:30 PM EDTF0Osceola, FL0.230
August 136:30 PM EDTF0Belknap, NH7.040
August 137:26 PM EDTF1Volusia, FL0.440
August 137:40 PM EDTF0Volusia, FL30.0201
August 138:26 PM EDTF1Osceola, FL2.0200
August 138:50 PM EDTF1Osceola, FL2.03,000

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.