Tornadoes · United States · Illinois · 2015

EF0 tornado, Forsyth, Illinois, July 11, 2015

This EF0 tornado ran 0.1 miles across Macon County on July 11, 2015, touching down at 9:25 PM CDT and reaching 50 yards wide. It killed nobody, and did $15,000 of property damage.

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
July 11, 2015
Touchdown
9:25 PM CDT (02:25 UTC)
Lifted
9:26 PM CDT (02:26 UTC)
On the ground
1 minutes
Path length
0.1 miles (0.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$15,000
County
Macon County
Touchdown point
39.928, -88.951
Lift-off point
39.929, -88.950
Record number
1507112025-01

What the Weather Service recorded

Several clusters of thunderstorms developed along and north of a warm front extending from northern Missouri into southern Illinois during the afternoon and evening of July 11th. One of the storms produced a brief tornado near Forsyth and some wind damage in Long Creek in Macon County. Elsewhere around central Illinois, torrential rainfall created localized flash flooding, across portions of west central Illinois where numerous roads were closed through the morning hours of July 12th due to high water.

A tornado touched down about 0.3 miles south of Forsyth at 9:25 PM CDT. The tornado snapped several trees at their tops, damaged a shed, destroyed a dog kennel, blew a garage door partially in, and created minor roof damage to two homes before quickly dissipating at 9:26 PM CDT.

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.

The county was under a severe thunderstorm watch, issued at 01:00 UTC and running to 05:32 UTC.

Issued (UTC)ExpiredProductOffice
18:40 UTC01:00 UTCSevere Thunderstorm WatchILX
00:55 UTC07:00 UTCFlood AdvisoryILX
01:00 UTC05:32 UTCSevere Thunderstorm WatchILX
03:09 UTC03:34 UTCSevere Thunderstorm WarningILX

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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 01:07 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

2.4 hours before the tornado, 39 km from the path. July 12, 2015.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2015-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1094 joules per kilogram, CIN -59, lifted condensation level 865 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 2015-07-12The 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 240 square meters per square second, 0 to 6 km bulk shear 38 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
1094 J/kg
Mixed-layer CIN
-59 J/kg
Surface CAPE
1273 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
240 m²/s²
0-3 km storm-relative helicity
371 m²/s²
Significant tornado parameter
0.9
Supercell composite
7.2
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

Lincoln, IL (KILX), 12:00Z

9.6 hours after it, 39 km from the path. July 12, 2015.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2015-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 606 joules per kilogram, CIN -145, lifted condensation level 877 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 2015-07-12The 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 79 square meters per square second, 0 to 6 km bulk shear 17 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
606 J/kg
Mixed-layer CIN
-145 J/kg
Surface CAPE
5 J/kg
Mixed-layer LCL
877 m above ground
0-6 km bulk shear
17 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.7 K/km

Open this sounding in Storm Lab

The radar

The Lincoln radar (KILX), 41 km away, was scanning. The volume nearest the touchdown began at 02:24 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
01:32 UTCHEAVY RAIN 1.75LincolnLogan, ILSTORM TOTAL RAINFALL SINCE 7 AM
01:35 UTCHEAVY RAIN 2.062 E LincolnLogan, ILSTORM TOTAL RAINFALL SINCE 7 AM THIS MORNING...MEASURED AT NWS-LINCOLN...STILL RAINING LIGHTLY.
02:15 UTCTSTM WND DMGForsythMacon, ILTREES BLOWN DOWN
03:02 UTCTSTM WND GST 62Decatur AirportMacon, IL
03:10 UTCTSTM WND DMGLong CreekMacon, ILDELAYED REPORT...TIME ESTIMATED. TREES DOWN AND SOME SIDING OFF HOUSES.

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

This ground now

The live radar over the trackEvery 2015 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

The other tornadoes of July 11, 2015

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 111:40 PM MDTEF0Jefferson, ID7.410
July 1110:24 PM CDTEF0Benson, ND0.125

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.