Tornadoes · United States · Pennsylvania · 2014

EF0 tornado, Knox Dale to Eleanor, Pennsylvania, August 21, 2014

From Knox Dale to Eleanor, this EF0 tornado ran 5.4 miles across Jefferson County on August 21, 2014, touching down at 4:27 PM EDT and reaching 50 yards wide. It killed nobody, and did $500 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
August 21, 2014
Touchdown
4:27 PM EDT (20:27 UTC)
Lifted
4:35 PM EDT (20:35 UTC)
On the ground
8 minutes
Path length
5.4 miles (8.6 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$500
County
Jefferson County
Touchdown point
41.070, -79.010
Lift-off point
41.017, -78.935
Record number
1408211427-01

What the Weather Service recorded

An upper level wave moving along a stalled front initiated thunderstorms that produced flash flooding and 2 weak tornadoes.

A brief EF-0 tornado was found from near Fuller and Center Roads to near the State Game Lands. Maximum estimated winds were 80 MPH with a path width of 20 yards. Damage was limited to hardwood trees with no structural damage.

A NWS damage survey found an EF-0 tornado occurred southeast of Knox dale to 1 mile east of Anita. The tornado was on the ground sporadically for around 5 miles, with a path width of 50 yards. Maximum winds were estimated at 80 MPH. No structural damage was noted but hardwood trees were damaged.

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

The warnings

11 minutes of warning. NWS PBZ issued a tornado warning for this county at 20:16 UTC, 11 minutes before the tornado touched down, in force until 20:45 UTC.

Issued (UTC)ExpiredProductOffice
19:50 UTC01:05 UTCFlash Flood WarningPBZ
20:16 UTC20:45 UTCTornado WarningPBZ
21:12 UTC00:15 UTCFlash Flood WarningPBZ
03:40 UTC05:30 UTCFlood AdvisoryPBZ

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 20:06 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.

Pittsburgh, PA (KAGC), 12:00Z

8.5 hours before the tornado, 118 km from the path. August 21, 2014.

Skew-T log-pSkew-T log-p diagram, Pittsburgh, PA at 12:00Z on 2014-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 324 joules per kilogram, CIN -33, lifted condensation level 1058 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, Pittsburgh, PA at 12:00Z on 2014-08-21The 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 24 square meters per square second, 0 to 6 km bulk shear 30 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
324 J/kg
Mixed-layer CIN
-33 J/kg
Surface CAPE
39 J/kg
Mixed-layer LCL
1058 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
100 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Pittsburgh, PA (KAGC), 00:00Z

3.5 hours after it, 118 km from the path. August 22, 2014.

Skew-T log-pSkew-T log-p diagram, Pittsburgh, PA at 00:00Z on 2014-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 213 joules per kilogram, CIN -2, lifted condensation level 651 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, Pittsburgh, PA at 00:00Z on 2014-08-22The 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 110 square meters per square second, 0 to 6 km bulk shear 34 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
213 J/kg
Mixed-layer CIN
-2 J/kg
Surface CAPE
665 J/kg
Mixed-layer LCL
651 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
110 m²/s²
0-3 km storm-relative helicity
129 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The radar

The State College radar (KCCX), 82 km away, was scanning. The volume nearest the touchdown began at 20:29 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
20:25 UTCTORNADO1 Sw FullerJefferson, PABRIEF TORNADO FROM NEAR FULLER AND CENTER HILL ROADS TO JUST WEST OF THE STATE GAME LANDS. DAMAGE WAS LIMITED TO HARDWOOD TREES. THE TORNADO WAS RATED EF0 ON THE ENHANCED FUJITA SCALE...WITH MAXIMUM WIND OF 80 MPH. SEE P
20:27 UTCTORNADO1 Se Knox DaleJefferson, PAPHOTOGRAPHIC EVIDENCE AND A DAMAGE SURVEY CONFIRMED A TORNADO WITH INTERMITTENT DAMAGE FROM NEAR KNOX DALE-PANIC ROAD AND CENTER HILL ROAD TO NEAR ANITA. DAMAGE WAS LIMITED TO TREES IN ROUGH AND FORESTED TERRAIN. NO STRU
20:35 UTCTSTM WND DMGPanicJefferson, PATREES DOWN PANIC-KNOXDALE ROAD
20:40 UTCTSTM WND DMG2 Ne Big RunJefferson, PATREES DOWN ON PIKE ROAD
20:41 UTCFLASH FLOODBrookvilleJefferson, PA2 FEET OF WATER ROUTE 322 BETWEEN BROOKVILLE AND REYNOLDSVILLE
20:42 UTCFLASH FLOOD2 S BrookvilleJefferson, PABELGIUMTOWN UNDER 2 FEET OF WATER.
20:45 UTCFLASH FLOODBaxterJefferson, PATOWN UNDER 2 FEET OF WATER
21:14 UTCFLASH FLOOD2 S SykesvilleJefferson, PAROUTE 119 CLOSED DUE TO FLOODING IN MULTIPLE LOCATIONS.
21:28 UTCTSTM WND DMGMahaffeyClearfield, PATREES REPORTED DOWN NEAR MAHAFFEY.
22:09 UTCTSTM WND DMGHoutzdaleClearfield, PATREE DOWN ON WIRES.
22:52 UTCFLOODMahaffeyClearfield, PAFLOODING REPORTED ON ROUTE 219 NEAR MAHAFFEY.

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

This ground now

The live radar over the trackEvery 2014 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

The other tornadoes of August 21, 2014

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 215:20 AM CDTEF0Cottonwood, MN0.150
August 214:25 PM EDTEF0Jefferson, PA0.520$500

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.