Tornadoes · United States · Illinois · 2023

EF0 tornado, Ames, Illinois, August 13, 2023

This EF0 tornado ran 0.4 miles across Monroe County on August 13, 2023, touching down at 5:35 PM CDT and reaching 10 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

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

  2. EF186 to 110 mph

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

  3. EF2111 to 135 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. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

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

  6. EF5over 200 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
EF0
Date
August 13, 2023
Touchdown
5:35 PM CDT (22:35 UTC)
Lifted
5:36 PM CDT (22:36 UTC)
On the ground
1 minutes
Path length
0.4 miles (0.6 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Monroe County
Touchdown point
38.167, -90.057
Lift-off point
38.167, -90.050
Record number
2308131635-01

The damage survey

2 damage points were recorded along this path by NWS LSX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 83 mph.

  • Photos relayed from broadcast media shows this shed with the door blown out and a back section of the shed blown out. Debris from the shed was carried downwind toward the pond on to the east.
  • Photos from house south of this point on Faust Rd. show a narrow path through a soybean field.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

Widespread showers and storms moved through the region on August 13th. One storm became severe and produced a brief tornado in far southern portion of Monroe County Illinois.

A brief, weak tornado formed near Ames Road, just north of intersection with Faust Road and tracked due east. It struck a shed, producing EF0 damage. Images show the debris from the shed was thrown into the pond down wind. Further east, photos show a narrow track through a soybean field north of Faust Road where it dissipated. Overall, the tornado was rated EF0 with a path length of 0.38 miles. The max path width was 10 yards. No deaths or injuries were reported.

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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:45 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), 12:00Z

10.6 hours before the tornado, 254 km from the path. August 13, 2023.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2023-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1 joules per kilogram, CIN -66, lifted condensation level 1330 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2023-08-13The 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 4 square meters per square second, 0 to 6 km bulk shear 29 knots.19395878Sfc1 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
1 J/kg
Mixed-layer CIN
-66 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1330 m above ground
0-6 km bulk shear
29 kt
0-1 km bulk shear
3 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1
0-3 km lapse rate
1.8 K/km

Open this sounding in Storm Lab

Lincoln, IL (KILX), 00:00Z

1.4 hours after it, 254 km from the path. August 14, 2023.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2023-08-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 130 joules per kilogram, CIN -4, lifted condensation level 1033 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2023-08-14The 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 29 square meters per square second, 0 to 6 km bulk shear 44 knots.19395878Sfc1 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
130 J/kg
Mixed-layer CIN
-4 J/kg
Surface CAPE
2129 J/kg
Mixed-layer LCL
1033 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
359 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The surface observations

Sparta (SAR), 31 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:35 UTC81.576.5110° 4 kt1014.6
20:55 UTC81.576.5130° 4 kt1014.2
21:15 UTC82.477160° 4 kt1014.6
21:35 UTC81.777140° 4 kt1013.9
21:55 UTC82.477.4160° 3 kt1013.9
22:15 UTC8377.7190° 5 kt1013.9VCTS
22:35 UTC82.477.4220° 6 kt1013.9
22:55 UTC82.677200° 10 kt1013.9VCTS
23:15 UTC80.277.5220° 6 kt91013.5+VCTSRA
23:35 UTC8078200° 9 kt1013.2VCTS
23:55 UTC78.677260° 3 kt1013.5VCTS
00:15 UTC7977.4250° 3 kt1013.5

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

The radar

The St Louis radar (KLSX), 81 km away, was scanning. The volume nearest the touchdown began at 22:36 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
22:35 UTCTORNADO1 N AmesMonroe, ILA brief, weak tornado formed near Ames Road (1N of Ames, IL) at 535PM and tracked due east, striking a shed and producing EF0 damage. Then it moved through a soybean field north of Faust Road where it dissipated at 536PM

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2023 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of August 13, 2023

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 137:14 PM CDTEF0Nobles, MN1.350$10,000
August 136:09 PM MSTEF0Pima, AZ0.125

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.