Tornadoes · United States · Florida · 2011

EF0 tornado, Christmas, Florida, January 17, 2011

This EF0 tornado ran 0.1 miles across Orange County on January 17, 2011, touching down at 11:03 AM EST and reaching 20 yards wide. It killed nobody.

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
January 17, 2011
Touchdown
11:03 AM EST (16:03 UTC)
Path length
0.1 miles (0.1 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Orange County
Touchdown point
28.490, -80.865
Lift-off point
28.490, -80.865
Record number
1101171003-01

What the Weather Service recorded

Several bow echos developed in the warm sector to the south of a warm front which lifted north across central Florida during the morning. As the cells raced northeast near 40 mph, a brief, weak tornado developed and impacted a rural area near the Orange and Brevard County line to the west of Port St. John. Minor wind damage from a fast moving cell also impacted several homes in Orlando.

An off duty USAF weather observer spotted a tornado with strong rotation and a debris cloud evident, to his west over a rural area of extreme eastern Orange County. Radar imagery indicated rotation within the cell, associated with the comma head of a bow echo.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

14 minutes of warning. NWS MLB issued a tornado warning for this county at 15:49 UTC, 14 minutes before the tornado touched down, in force until 16:45 UTC.

Issued (UTC)ExpiredProductOffice
15:49 UTC16:45 UTCTornado WarningMLB
17:00 UTC20:41 UTCTornado WatchMLB
17:42 UTC18:45 UTCTornado WarningMLB

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 12:34 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.

Cape Canaveral, FL (KXMR), 12:00Z

4.1 hours before the tornado, 36 km from the path. January 17, 2011.

Skew-T log-pSkew-T log-p diagram, Cape Canaveral, FL at 12:00Z on 2011-01-17Temperature 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 -84623, lifted condensation level 1230 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, Cape Canaveral, FL at 12:00Z on 2011-01-17The 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 43 square meters per square second, 0 to 6 km bulk shear 43 knots.1939587897117Sfc1 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
-84623 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1230 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
256 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.6 K/km

Open this sounding in Storm Lab

Cape Canaveral, FL (KXMR), 00:00Z

7.9 hours after it, 36 km from the path. January 18, 2011.

Skew-T log-pSkew-T log-p diagram, Cape Canaveral, FL at 00:00Z on 2011-01-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 6 joules per kilogram, CIN -109, lifted condensation level 634 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, Cape Canaveral, FL at 00:00Z on 2011-01-18The 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 129 square meters per square second, 0 to 6 km bulk shear 47 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
6 J/kg
Mixed-layer CIN
-109 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
634 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
133 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The radar

The Melbourne radar (KMLB), 47 km away, was scanning. The volume nearest the touchdown began at 16:04 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
15:07 UTCTSTM WND GST 395 Sse ConwayOrange, FLKMCO ASOS REPORTED WIND GUST OF 34 KTS/39 MPH
16:06 UTCFUNNEL CLOUD3 Nw Port Saint JohnBrevard, FL
16:13 UTCTORNADO4 W Port Saint JohnBrevard, FLOBSERVER REPORTED ROTATING FUNNEL WITH DEBRIS CLOUD WEST OF THE INTERSECTION OF FAY BLVD AND I-95. THIS IS A CORRECTION TO THE LOCATION OF THE PREVIOUS STORM REPORT.
16:13 UTCTORNADO6 W Port Saint JohnOrange, FLOBSERVER REPORTED ROTATING FUNNEL WITH DEBRIS CLOUD NEAR THE INTERSECTION OF FAY BLVD AND I-95.
16:21 UTCTSTM WND GST 465 Wsw Playalinda BeachBrevard, FLKTTS REPORTED 40 KT/46 MPH WIND GUST.
16:31 UTCTSTM WND GST 476 Nne Cape CanaveralBrevard, FLKXMR REPORTED 41 KT/47 MPH WIND GUST.
18:58 UTCTSTM WND GST 48N Patrick Airforce BaseBrevard, FLKCOF REPORTED WIND GUST OF 42 KTS/48 MPH.
18:58 UTCNON-TSTM WND GST 48N Patrick Airforce BaseBrevard, FLKCOF REPORTED WIND GUST OF 42 KTS/48 MPH.

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.