Tornadoes · United States · Illinois · 1999

F1 tornado, New Douglas, Illinois, April 8, 1999

This F1 tornado ran 1.0 miles across Madison County on April 8, 1999, touching down at 10:18 PM CDT. It killed nobody and injured 1.

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 mphthis tornado

    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.

The record

Rating
F1
Date
April 8, 1999
Touchdown
10:18 PM CDT (03:18 UTC)
Path length
1.0 miles (1.6 km)
Path width
0 yards (0 m)
Deaths
0
Injuries
1
County
Madison County
Touchdown point
38.950, -89.680
Lift-off point
38.950, -89.670
Record number
344

What the Weather Service recorded

A small non-supercell tornado associated with a line of thunderstorms caused 1 injury and damage to 3 farms New Douglas area. Most of the damage was to barns and outbuildings. One home had the roof and a couple of walls of an addition blown away. The garage was also severely damaged. One man suffered cuts and bruises when hit by flying debris.

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

The warnings

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 forecast that day

The Storm Prediction Center had this point in a High Risk. The outlook in force was issued at 00:56 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.

Lincoln, IL (KILX), 00:00Z

3.3 hours before the tornado, 162 km from the path. April 9, 1999.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 1999-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 859 joules per kilogram, CIN -35, lifted condensation level 1075 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, Lincoln, IL at 00:00Z on 1999-04-09The 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 344 square meters per square second, 0 to 6 km bulk shear 73 knots.1939587897Sfc1 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
859 J/kg
Mixed-layer CIN
-35 J/kg
Surface CAPE
1289 J/kg
Mixed-layer LCL
1075 m above ground
0-6 km bulk shear
73 kt
0-1 km bulk shear
34 kt
0-1 km storm-relative helicity
344 m²/s²
0-3 km storm-relative helicity
449 m²/s²
Significant tornado parameter
1.9
Supercell composite
8.7
0-3 km lapse rate
6.6 K/km

Open this sounding in Storm Lab

Lincoln, IL (KILX), 12:00Z

8.7 hours after it, 162 km from the path. April 9, 1999.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 1999-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2 joules per kilogram, CIN -23, lifted condensation level 1038 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, Lincoln, IL at 12:00Z on 1999-04-09The 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 75 square meters per square second, 0 to 6 km bulk shear 56 knots.1939587897117Sfc1 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
2 J/kg
Mixed-layer CIN
-23 J/kg
Surface CAPE
5 J/kg
Mixed-layer LCL
1038 m above ground
0-6 km bulk shear
56 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The radar

The St Louis radar (KLSX), 92 km away, was scanning. The volume nearest the touchdown began at 03:20 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.

This ground now

The live radar over the trackEvery 1999 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of April 8, 1999

46 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 811:00 AM CDTF1Hamilton, NE4.050$300,000
April 811:54 AM CDTF1Merrick, NE3.040$200,000
April 811:56 AM CDTF0Nance, NE1.010$10,000
April 812:22 PM CDTF0Boone, NE1.040$10,000
April 81:06 PM CDTF1Colfax, NE4.0150$540,000
April 81:07 PM CDTF1Saunders, NE1.5400$380,000
April 81:12 PM CDTF0Saunders, NE3.570$40,000
April 81:33 PM CDTF1Story, IA2.002$800,000
April 81:48 PM CDTF0Washington, NE0.130$10,000
April 82:08 PM CDTF0Fremont, IA0.040
April 82:18 PM CDTF0Pottawattamie, IA0.360
April 82:22 PM CDTF1Page, IA5.070$10,000
April 82:30 PM CDTF1Andrew, MO13.502$750,000
April 82:36 PM CDTF1Page, IA8.04401$100,000
April 82:38 PM CDTF1Montgomery, IA8.060$40,000
April 82:48 PM CDTF1Page, IA9.0100$20,000
April 82:54 PM CDTF0Montgomery, IA5.080$10,000
April 82:54 PM CDTF4Taylor, IA49.01,0003$2.7 million
April 83:48 PM CDTF4Union, IA56.01,2501$2.4 million
April 84:20 PM CDTF2Carroll, MO53.52802$1.9 million
April 84:20 PM CDTF1Livingston, MO7.00$250,000
April 85:00 PM CDTF0Polk, IA0.230$40,000
April 85:13 PM CDTF2Warren, IA32.00$120,000
April 85:18 PM CDTF3Lucas, IA39.005$1.4 million
April 85:25 PM CDTF2Macon, MO17.0270$1.0 million
April 85:30 PM CDTF1Cooper, MO4.00$750,000
April 85:55 PM CDTF2Boone, MO4.01205
April 86:05 PM CDTF2Lewis, MO16.01502$2.1 million
April 86:05 PM CDTF2Boone, MO10.0120
April 86:15 PM CDTF3Davis, IA16.0300$650,000
April 86:25 PM CDTF0Jefferson, IA0.110
April 86:25 PM CDTF0Jefferson, IA0.110
April 86:30 PM CDTF1Audrain, MO10.0100
April 86:30 PM CDTF1Cole, MO12.0200
April 86:35 PM CDTF3Hancock, IL7.5200$15 million
April 87:36 PM EDTF0Barnwell, SC0.550$1,000
April 87:47 PM EDTF1Allendale, SC9.050$30,000
April 87:00 PM CDTF1Osage, MO8.0200$1.0 million
April 87:15 PM CDTF0Webster, MO0.10$20,000
April 87:34 PM CDTF2Pike, MO to IL27.3120$150,000
April 87:35 PM CDTF0Henderson, IL20.010
April 88:10 PM CDTF1Scott, IL4.0120$100,000
April 88:27 PM CDTF1Morgan, IL9.5200
April 88:45 PM CDTF1Morgan, IL9.333316$1.8 million
April 810:35 PM CDTF1Piatt, IL3.510013$150,000
April 811:32 PM CDTF0Cumberland, IL0.30$100,000

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.