Tornadoes · United States · North Carolina · 2012

EF0 tornado, Zebulon to Rockton, North Carolina, September 18, 2012

From Zebulon to Rockton, this EF0 tornado ran 0.5 miles across Wake County on September 18, 2012, touching down at 3:38 PM EDT and reaching 30 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
September 18, 2012
Touchdown
3:38 PM EDT (19:38 UTC)
Lifted
3:41 PM EDT (19:41 UTC)
On the ground
3 minutes
Path length
0.5 miles (0.8 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Wake County
Touchdown point
35.820, -78.340
Lift-off point
35.827, -78.337
Record number
1209181338-01

What the Weather Service recorded

Multiple line segments of strong to severe storms developed over North Carolina as a compact but potent shortwave emanating from the gulf coast region and along the eastern flanks of a full latitude trough moved through the Carolinas. The accompanying 50 to 60 knot mid level jet within a moist and unstable air mass produced scattered thunderstorm wind damage and an isolated EF-0 tornado near Zebulon.

A NWS damage survey found that a weak EF-0 tornado briefly touched down just west of the town of Zebulon. A well-defined damage path was found in a stand of trees of about one-half mile long and about 30 yards wide. Based on the type of trees affected and the magnitude of damage, the wind speeds are believed to have topped out at around 75 mph. No structural damage was found and there were no injuries or fatalities.

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

The warnings

0 minutes of warning. NWS RAH issued a tornado warning for this county at 19:38 UTC, 0 minutes before the tornado touched down, in force until 19:47 UTC.

The county was under a tornado watch, issued at 13:45 UTC and running to 20:40 UTC.

Issued (UTC)ExpiredProductOffice
13:45 UTC20:40 UTCTornado WatchRAH
18:51 UTC19:45 UTCSevere Thunderstorm WarningRAH
19:04 UTC21:30 UTCFlood AdvisoryRAH
19:37 UTC21:10 UTCFlash Flood WarningRAH
19:38 UTC19:47 UTCTornado WarningRAH
03:46 UTC05:27 UTCFlood AdvisoryRAH

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 Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:24 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.

Greensboro/Hi Pt, NC (KGSO), 12:00Z

7.6 hours before the tornado, 143 km from the path. September 18, 2012.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 12:00Z on 2012-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 533 joules per kilogram, CIN 0, lifted condensation level 545 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, Greensboro/Hi Pt, NC at 12:00Z on 2012-09-18The 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 221 square meters per square second, 0 to 6 km bulk shear 35 knots.19395878Sfc1 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
533 J/kg
Mixed-layer CIN
0 J/kg
Surface CAPE
385 J/kg
Mixed-layer LCL
545 m above ground
0-6 km bulk shear
35 kt
0-1 km bulk shear
32 kt
0-1 km storm-relative helicity
221 m²/s²
0-3 km storm-relative helicity
313 m²/s²
Significant tornado parameter
0.5
Supercell composite
4.1
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

Greensboro/Hi Pt, NC (KGSO), 00:00Z

4.4 hours after it, 143 km from the path. September 19, 2012.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 00:00Z on 2012-09-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 159 joules per kilogram, CIN -25, lifted condensation level 660 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, Greensboro/Hi Pt, NC at 00:00Z on 2012-09-19The 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 -4 square meters per square second, 0 to 6 km bulk shear 62 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
159 J/kg
Mixed-layer CIN
-25 J/kg
Surface CAPE
303 J/kg
Mixed-layer LCL
660 m above ground
0-6 km bulk shear
62 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
66 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

The surface observations

Louisburg/Franklin_cnty_arpt (LHZ), 22 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
17:55 UTC180° 14 kt201008.1
18:15 UTC170° 12 kt191007.1
18:35 UTC180° 10 kt1007.1
18:55 UTC180° 10 kt1007.1
19:15 UTC180° 8 kt1007.5
19:35 UTC200° 15 kt211008.1+RA
19:55 UTC210° 5 kt1007.8RA
20:15 UTC180° 6 kt1008.1RA
20:35 UTC0° 0 kt1008.1-RA
20:55 UTC0° 0 kt1008.8+RA
21:15 UTC0° 0 kt1008.5-RA
21:35 UTC0° 0 kt1008.1

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

The radar

The Raleigh/Durham radar (KRAX), 22 km away, was scanning. The volume nearest the touchdown began at 19:36 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
19:38 UTCTORNADO3 Nne WendellWake, NCAN NWS DAMAGE SURVEY THIS MORNING HAS CONCLUDED THAT A WEAK EF-0 TORNADO BRIEFLY TOUCHED DOWN TUESDAY AFTERNOON JUST WEST OF THE TOWN OF ZEBULON... NC. THE TORNADO DAMAGE WAS FOUND IN A STAND OF TREES AS A WELL-DEFINED D
19:42 UTCTSTM WND DMG4 Sw PilotWake, NCRESIDENT ON KARIAL COURT HEARD TORNADO WARNING AND SOUGHT SHELTER. UPON LEAVING SHELTER... 60-FOOT TREE ACROSS STREET WAS TOPPED AT ABOUT 30-FOOT LEVEL WITH BRANCHES BLOWN DOWN. TIME ESTIMATED.
19:43 UTCTSTM WND DMG1 N BensonJohnston, NCTREES DOWN IN ROADWAY.
20:00 UTCFLASH FLOOD2 Ene RaleighWake, NCSEVERAL REPORTS OF HIGH WATER AROUND RALEIGH... INCLUDING WATER ONE FOOT DEEP AT SIX FORKS AND WAKE FOREST ROAD... AND ROADWAY FLOODED AT ATLANTIC AVE AND 440. ROAD BEING BLOCKED BY POLICE AT TIME OF CALL.
21:00 UTCFLASH FLOOD2 Ene RaleighWake, NCFLASH FLOODING ABATED. NO KNOWN ROAD CLOSURES.

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

This ground now

The live radar over the trackEvery 2012 tornado in North CarolinaEvery tornado in North Carolina since 1950Warnings in force in North Carolina nowThe forecast where you are

The other tornadoes of September 18, 2012

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 184:20 PM EDTEF0Jones, NC5.0300$20,000

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.