Tornadoes · United States · Delaware · 2004

F2 tornado, (Ilg)Wilmington Arpt, Delaware, September 28, 2004

This F2 tornado ran 5.0 miles across New Castle County on September 28, 2004, touching down at 4:14 PM EDT and reaching 150 yards wide. It killed nobody, and did $1.0 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.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mphthis tornado

    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. 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.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. 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.

  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
F2
Date
September 28, 2004
Touchdown
4:14 PM EDT (20:14 UTC)
Path length
5.0 miles (8.0 km)
Path width
150 yards (137 m)
Deaths
0
Injuries
0
Property damage
$1.0 million
County
New Castle County
Touchdown point
39.680, -75.600
Lift-off point
39.730, -75.580
Record number
618

What the Weather Service recorded

An F2 (on the Fujita scale) tornado touched down in northern New Castle County with maximum winds estimated at 130 mph. The path length was 5.0 miles long with a maximum path width of 150 yards. The tornado touched down near and was observed at the New Castle County Airport. The northern end of the tornado track was in Elsmere. Significant damage did occur along the path of this tornado, particularly to some of the planes at the airport and industrial buildings near the airport. In addition, five persons were injured.The tornado damaged five C-130 cargo planes at the New Castle County Airport, caused thousands of pounds of jet fuel to spill and damaged hangers. It tore through the Newport Industrial Park along Delaware State Route 141. It tossed long strips of metal siding into the air and onto roads. Windows were shattered, walls peeled away and trees and light poles were snapped. The roof and whole side of the United Electric Supply building was torn away. Delaware State Route 141 and some nearby side streets were closed. Gas service was shut off to prevent explosions. On Bellecor Drive, a self-storage facility suffered major damage. One man at the business was injured after he was trapped under a fallen refrigerator. Three people were injured at the airport itself. A man in Elsmere was hit by a fallen tree limb. The tornado also caused damaged to homes in Wilmington Manor and Chelsea Estates near the airport. In Elsmere, the tornado tore shingles and vent covers from the Corpus Christi Elementary School. The ensuing heavy rain damaged the gymnasium. In the Red Clay Consolidated School District, the tornado also caused minor damage to the Richardson Park Elementary School.

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

The warnings

3 minutes of warning. NWS PHI issued a tornado warning for this county at 20:11 UTC, 3 minutes before the tornado touched down, in force until 20:45 UTC.

Issued (UTC)ExpiredProductOffice
18:12 UTC19:15 UTCSevere Thunderstorm WarningPHI
18:36 UTC21:30 UTCFlash Flood WarningPHI
18:36 UTC21:30 UTCFlash Flood WarningPHI
19:14 UTC20:00 UTCSevere Thunderstorm WarningPHI
20:01 UTC20:45 UTCSevere Thunderstorm WarningPHI
20:11 UTC20:45 UTCTornado WarningPHI
20:11 UTC20:45 UTCTornado WarningPHI
20:41 UTC22:00 UTCSevere Thunderstorm WarningPHI
21:30 UTC00:30 UTCFlash Flood WarningPHI
21:30 UTC00:30 UTCFlash Flood WarningPHI
00:05 UTC06:00 UTCFlash Flood WarningPHI
00:05 UTC06:00 UTCFlash Flood WarningPHI

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:30 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.

Phillips Aaf/Abe, MD (KAPG), 12:00Z

8.2 hours before the tornado, 51 km from the path. September 28, 2004.

Skew-T log-pSkew-T log-p diagram, Phillips Aaf/Abe, MD at 12:00Z on 2004-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 95 joules per kilogram, CIN -78, lifted condensation level 631 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Phillips Aaf/Abe, MD at 12:00Z on 2004-09-28The 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 109 square meters per square second, 0 to 6 km bulk shear 41 knots.193958Sfc1 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
95 J/kg
Mixed-layer CIN
-78 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
631 m above ground
0-6 km bulk shear
41 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4
0-3 km lapse rate
4.4 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 2004 tornado in DelawareEvery tornado in Delaware since 1950Warnings in force in Delaware nowThe forecast where you are

The other tornadoes of September 28, 2004

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 284:58 AM EDTF1Pittsylvania, VA12.41001
September 283:30 PM EDTF0Camden, NJ2.517$100,000
September 284:00 PM EDTF0Calvert, MD0.350$40,000

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.