F0 tornado, Manlius to Neponset, Illinois, May 18, 2000

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

May 18, 2000

Touchdown

4:00 PM CDT (21:00 UTC)

Path length

0.1 miles (0.2 km)

Path width

10 yards (9 m)

Deaths

0

Injuries

0

Property damage

$10,000

County

Bureau County

Touchdown point

41.300, -89.800

Lift-off point

41.300, -89.800

Record number

859

A frontal boundary meandering about Southern Iowa and Central Illinois lifted into Central Iowa and North Central Illinois by afternoon. A nearly stacked low center over the Mid Missouri River Valley underwent filling as it shifted eastward across Southern Iowa and Central Illinois. Much of Northern Illinois along and north of Interstate 88 was thrusted into the warm sector where temperatures climbed into the upper 70s to lower 80s. Meanwhile, areas north of the boundary were quite cool with a brisk northeast surface wind and plenty of cloud cover keeping temperatures down in the 60s. 12z soundings from KILX and KDVN indicated very steep lapse rates with Cape values of 2000-3000 J-kg. Thunderstorms quickly erupted along the boundary from Central Iowa through Northeast Iowa into Northern Illinois by late morning, and continued through the afternoon. The storms produced large hail, heavy rain, damaging winds and several tornadoes over portions of Northwest Illinois. Thunderstorm interaction with the frontal boundary was believed to be the culprit for spawning 6 weak and short lived tornadoes across Henry and Bureau Counties. The only damage occurring with the tornadoes was in Manlius and Neponset where large trees and signs were blown down. High winds, associated with a possible gustnado, blew down the back wall and knocked out several windows of an abandoned grocery store in Cambridge. The glass and bricks were hurled to the ground, causing damage to a truck parked on one side of the building. The high winds also downed several trees and power lines. Power was knocked out to Cambridge and surrounding areas for almost 4 hours.

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

17 minutes of warning. NWS DVN issued a tornado warning for this county at 20:43 UTC, 17 minutes before the tornado touched down, in force until 21:30 UTC.

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 Moderate Risk. The outlook in force was issued at 19:52 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.

The Quad Cities radar (KDVN), 74 km away, was scanning. The volume nearest the touchdown began at 21:00 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 2000 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

36 more were confirmed in the United States that day.

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.