Tornadoes · United States · Pennsylvania · 1993
F1 tornado, Neshaminy, Pennsylvania, September 27, 1993
This F1 tornado ran 2.5 miles across Bucks County on September 27, 1993, touching down at 2:50 PM EDT and reaching 100 yards wide. It killed nobody, and did $500,000 to $5 million of property damage.
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.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- F1
- Date
- September 27, 1993
- Touchdown
- 2:50 PM EDT (18:50 UTC)
- Path length
- 2.5 miles (4.0 km)
- Path width
- 100 yards (91 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $500,000 to $5 million
- County
- Bucks County
- Touchdown point
- 40.230, -75.130
- Record number
- 1091
What the Weather Service recorded
The tornado touched down near Neshaminy High School and moved NE through Langhorne to near Country Club in Yardley. In addition to numerous trees downed, extensive structural damage occurred as the twisted swept through the county. In one instance, the tornado ripped the roof off of an orchard warehouse on Woodbourne Road in Middletown township. The roof landed in the road over 100 feet away. One car in the parking lot was damaged. As a result of the downed utility poles and trees, 20,000 customers lost power countywide and three schools cancelled classes because of power outages. Although no injuries resulted from the tornado and associated thunderstorm, in a related incidence, a Bell of PA technician on a repair call in Eastown Township, Chester County, was killed when he came in contact with a downed power line.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
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.
Atlantic City In, NJ (KACY), 12:00Z
6.8 hours before the tornado, 102 km from the path. September 27, 1993.
- Mixed-layer CAPE
- 1090 J/kg
- Mixed-layer CIN
- -41 J/kg
- Surface CAPE
- 656 J/kg
- Mixed-layer LCL
- 834 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 47 m²/s²
- 0-3 km storm-relative helicity
- 144 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 4.9
- 0-3 km lapse rate
- 4.8 K/km
The surface observations
Willow Grove Nas (NXX), 4 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 00:00 UTC |
From the Iowa Environmental Mesonet's archive of airport observations.
This ground now
The live radar over the trackEvery 1993 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are
The other tornadoes of September 27, 1993
10 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| September 27 | 11:00 AM EDT | F1 | Page, VA | 0.5 | 100 | $50,000 to $500,000 | ||
| September 27 | 11:58 AM EDT | F2 | Fauquier, VA | 3.0 | 100 | 2 | $50,000 to $500,000 | |
| September 27 | 12:42 PM EDT | F1 | Montgomery, MD | 0.2 | 50 | $50 to $500 | ||
| September 27 | 1:33 PM EDT | F0 | Fairfax, VA | 0.2 | 13 | $50 to $500 | ||
| September 27 | 1:35 PM EDT | F2 | New Castle, DE | 10.0 | 100 | $5,000 to $50,000 | ||
| September 27 | 1:55 PM EDT | F1 | Cecil, MD | 6.0 | 30 | $5,000 to $50,000 | ||
| September 27 | 2:00 PM EDT | F1 | New Castle, DE | 7.0 | 50 | $5,000 to $50,000 | ||
| September 27 | 2:15 PM EDT | F1 | Anne Arundel, MD | 8.0 | 23 | 2 | $500 to $5,000 | |
| September 27 | 2:15 PM EDT | F1 | Delaware, PA | 3.0 | 200 | $500,000 to $5 million | ||
| September 27 | 9:20 PM EDT | F1 | Carteret, NC | 2.0 | 20 | $500,000 to $5 million |
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.