Tornadoes · United States · Florida · 2011

EF0 tornado, Zephyr Hills Muni Ar, Florida, July 7, 2011

This EF0 tornado ran 0.2 miles across Pasco County on July 7, 2011, touching down at 5:05 PM EDT and reaching 20 yards wide. It killed nobody, and did $20,000 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
July 7, 2011
Touchdown
5:05 PM EDT (21:05 UTC)
Lifted
5:07 PM EDT (21:07 UTC)
On the ground
2 minutes
Path length
0.2 miles (0.4 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
Property damage
$20,000
County
Pasco County
Touchdown point
28.209, -82.162
Lift-off point
28.211, -82.159
Record number
1107071505-01

What the Weather Service recorded

Deep tropical moisture was in place across the area as a tropical wave slowly moved over the area. This allowed for numerous heavy showers and thunderstorms with a brief tornado spawning from boundary collisions.

A brief EF0 tornado resulted when a westward moving thunderstorm merged with a northeastward moving thunderstorm over the Zephyrhills area. Damage occurred to some manufactured homes near Chancey Road, with two structures sustaining minor roof damage, two having minor siding damage, and some lawn furniture was scattered.

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
21:07 UTC22:31 UTCFlood AdvisoryTBW
21:11 UTC22:18 UTCFlood AdvisoryTBW

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 19:56 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

9.1 hours before the tornado, 61 km from the path. July 7, 2011.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 12:00Z on 2011-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2119 joules per kilogram, CIN -3, lifted condensation level 562 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 12:00Z on 2011-07-07The 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 4 square meters per square second, 0 to 6 km bulk shear 11 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
2119 J/kg
Mixed-layer CIN
-3 J/kg
Surface CAPE
2325 J/kg
Mixed-layer LCL
562 m above ground
0-6 km bulk shear
11 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

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

2.9 hours after it, 61 km from the path. July 8, 2011.

Skew-T log-pSkew-T log-p diagram, Tampa Bay, FL at 00:00Z on 2011-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 237 joules per kilogram, CIN -55, lifted condensation level 620 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 2011-07-08The 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 -23 square meters per square second, 0 to 6 km bulk shear 16 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
237 J/kg
Mixed-layer CIN
-55 J/kg
Surface CAPE
419 J/kg
Mixed-layer LCL
620 m above ground
0-6 km bulk shear
16 kt
0-1 km bulk shear
4 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

The surface observations

Plant City (PCM), 23 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:15 UTC89.673.40° 0 kt1012.9
19:35 UTC89.671.60° 0 kt1012.5
19:55 UTC91.471.6180° 3 kt1012.5
20:15 UTC84.275.2240° 10 kt191012.9-RA
20:35 UTC78.875.2260° 12 kt1012.9DZ
20:55 UTC7775.2310° 6 kt1013.2-RA
21:15 UTC7775.20° 1013.9-RA
21:35 UTC7775.270° 8 kt1013.9+RA
21:55 UTC7775.2170° 3 kt1013.5RA
22:15 UTC7775.20° 0 kt1013.9+RA
22:35 UTC7775.2260° 3 kt1013.2RA
22:55 UTC7775.2220° 4 kt1013.2RA

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

The radar

The Tampa radar (KTBW), 61 km away, was scanning. The volume nearest the touchdown began at 21:05 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
21:05 UTCTSTM WND DMG2 Sse ZephyrhillsPasco, FLPASCO EMERGENCY MANAGERS REPORTED 3 MOBILE HOMES WITH ROOF DAMAGE AT EMERALD POINTE RV RESORT ALONG CHANCEY ROAD.
21:05 UTCTORNADO2 Sse ZephyrhillsPasco, FLON THURSDAY...A WESTWARD MOVING THUNDERSTORM MERGED WITH A NORTHEASTWARD MOVING THUNDERSTORM OVER THE ZEPHYRHILLS AREA. A BRIEF EF0 TORNADO RESULTED AND CAUSED DAMAGE TO SOME MANUFACTURED HOMES ON CHANCEY ROAD. TWO STRUC

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2011 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.