F0 tornado, Yorkville, Illinois, July 27, 2003

1. F040 to 72 mphthis tornado

   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 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. 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.

Rating

F0

Date

July 27, 2003

Touchdown

1:26 PM CDT (18:26 UTC)

Path length

1.0 miles (1.6 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

County

Kendall County

Touchdown point

41.630, -88.450

Lift-off point

41.630, -88.450

Record number

515

A line of severe thunderstorms moved east across north central Illinois during the early afternoon hours of July 27th. Additional thunderstorms developed ahead of the first line across the southern portions of the Chicago Metro area producing very heavy rain and widespread flooding. As the first line of severe storms reached Lee county, numerous trees, tree limbs and power lines were blown down in Amboy in Lee county. Trees were blown down onto houses in West Brooklyn, also in Lee county. Winds as high as 65 mph blew down trees, large tree limbs and power lines across many locations in La Salle county. Trees were blown down in La Salle. Trees were uprooted near Lake Holiday in far northeast La Salle county. Large tree limbs were blown down in Mendota, Norway and one mile east of Serena. A grain bin was crushed and partially lifted off its base in Ottawa and a tree fell onto a car in Seatonville, both in LaSalle county. Wind damage was widespread across Kendall county as well. Trees, large tree limbs and power lines were blown down in Plano, Newark and Oswego as well as many rural parts of the county. Trees were blown down blocking Illinois Route 71 west of Oswego. Trees 20 inches in diameter were blown down southeast of Plano along Lynwood Drive. Southwest of Plano, a large tree limb fell onto a roof and broke a skylight. Winds gusted to 74 mph in Sandwich in De Kalb county, where numerous large trees were blown down or uprooted and a 20 inch diameter tree fell onto house. Several trees and tents were blown down at an Antique show in Sandwich in DeKlab county where one person suffered a broken arm and another was hit in the head by a falling tent pole. Canopies were also blown off of stores in Sandwich. A two and a half foot diameter tree was snapped at its base in Morris in Grundy county. A gust to 60 mph was reported in Naperville in Will county. A one foot diameter tree was snapped in half on Winthrop Street, east of Larkin and north of Black Roads in Joliet. Large tree limbs and power lines were blown down in Kankakee. A tree fell onto power lines in Sheldon in Iroquois county.In addition to the strong winds and wind damage, very heavy rain fell across much of Will and southern Cook counties. Most of the rain fell in a two hour period with 5.00 inches reported in Shorewood, 4.90 inches at the National Weather Service office in Romeoville, 4.10 inches in Midlothian, 4.00 inches in Joliet, 3.56 inches in Orland Park, 3.50 inches in Plainfield and South Holland, and 2.05 inches in Plano in Kendall county. Widespread street flooding was reported across all of north and central Will and southern Cook counties and many homes and businesses suffered water and flood damage. Retention ponds were flooded and backing up into yards and streets in Plainfield in Will county. Creeks were overflowing their banks in Midlothian in Cook county. Several roads had two to four feet of standing water and were impassible, some roads were partially washed away. Several cars were submerged at the intersection of Lagrange and Nebraska streets in Frankfort in Will county. A Will county sheriff's car was destroyed when it pulled into a flooded subdivision and sank. Several people had to be rescued from their cars after becoming trapped by flood waters in Frankfort, Lockport, Joliet, and Plainfield in Will county. A creek bridge was washed away in Lockport township. A man indirectly died from the flooding after walking into his flooded basement and being shocked because the water was in contact with electricity. An alley between Illinois and Main Streets in Lemont in Cook county was partially washed away by fast flowing water. 100 homes and 13 businesses were flooded in Lemont. Flood waters surrounded several buildings in Tinely Park. A 15 foot berm was washed away in unicorpated Palos Township which caused massive street and basement flooding in the Sandberg Glen subdivision. Street flooding was also reported in Plano in Kendall county.

A weak tornado touchdown near the Hideaway Lake Camp near Yorkville in Kendall county. The main line of thunderstorms had already moved east of the area when a small thunderstorm developed near Yorkville and quickly interacted with a lake breeze moving west through the same area. This interaction helped to form a circulation which spun up as a weak tornado. Numerous trees were damaged and some were blown down. Damage occurred to several trailers and campers from the falling trees and tree limbs. The tornado appeared to skip along the ground with the strongest winds staying aloft affecting mainly the trees. The tornado lasted about two minutes.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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 Storm Prediction Center had this point in a Slight Risk. The outlook in force was issued at 16:03 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 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.

Chicago/Aurora (ARR), 16 km from the path, in the two hours either side.

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

The Chicago radar (KLOT), 31 km away, was scanning. The volume nearest the touchdown began at 18:27 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.

The live radar over the trackEvery 2003 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.