Tornadoes · United States · Minnesota · 2003

F0 tornado, Sleepy Eye, Minnesota, May 14, 2003

This F0 tornado ran 2.0 miles across Brown County on May 14, 2003, touching down at 12:50 PM CDT and reaching 25 yards wide. It killed nobody.

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 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.

The record

Rating
F0
Date
May 14, 2003
Touchdown
12:50 PM CDT (17:50 UTC)
Path length
2.0 miles (3.2 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Brown County
Touchdown point
44.300, -94.670
Lift-off point
44.300, -94.630
Record number
75

What the Weather Service recorded

Tornado touched down just west of an oats field, moved across a grassy field, crossed the Cottonwood River, then dissipated. There were a few broken trees near the Cottonwood River, but no damage was caused to any structure. The oats were just coming out of the ground and were laid down only for about 12 hours before returning to normal growth.

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.

Issued (UTC)ExpiredProductOffice
18:43 UTC19:30 UTCSevere Thunderstorm WarningMPX

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 General Thunderstorms Risk. The outlook in force was issued at 12:56 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.

Minneapolis, MN (KMPX), 12:00Z

5.8 hours before the tornado, 103 km from the path. May 14, 2003.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2003-05-14Temperature 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 -38, lifted condensation level 579 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, Minneapolis, MN at 12:00Z on 2003-05-14The 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 18 knots.1939Sfc1 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
-38 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
579 m above ground
0-6 km bulk shear
18 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

6.2 hours after it, 103 km from the path. May 15, 2003.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2003-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -90326, lifted condensation level 683 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2003-05-15The 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 -43 square meters per square second, 0 to 6 km bulk shear 3 knots.1939Sfc1 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
0 J/kg
Mixed-layer CIN
-90326 J/kg
Surface CAPE
1 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
3 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
-43 m²/s²
0-3 km storm-relative helicity
-14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.0 K/km

Open this sounding in Storm Lab

The surface observations

New Ulm Municipal (ULM), 12 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
15:56 UTC64.455.4150° 12 kt1007.8
16:16 UTC64.455.4130° 11 kt151008.1
16:20 UTC64.455.4130° 11 kt151008.1
16:56 UTC64.455.4130° 11 kt1007.8
17:18 UTC66.255.4130° 11 kt1007.5VCTS
17:20 UTC66.255.4130° 11 kt1007.5
17:36 UTC66.257.2130° 11 kt1007.1VCTS
17:40 UTC66.257.2130° 11 kt1007.1
17:56 UTC66.255.4110° 17 kt1006.1TS
18:17 UTC57.253.6300° 7 kt171007.1-TSRA
18:20 UTC57.253.6300° 7 kt171007.1
18:37 UTC57.255.450° 13 kt171007.5+TSRA
18:40 UTC57.255.450° 13 kt171007.5
18:56 UTC57.255.4100° 7 kt1007.5-TSRA
19:16 UTC53.653.6330° 8 kt1008.1-TSRA
19:20 UTC53.653.6330° 8 kt1008.1
19:36 UTC51.851.8280° 4 kt1007.8-VCTSRA
19:40 UTC51.851.8280° 4 kt1007.8

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

The radar

The Minneapolis radar (KMPX), 105 km away, was scanning. The volume nearest the touchdown began at 17:51 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 2003 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of May 14, 2003

10 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 145:59 PM CDTF0Ford, IL1.050$2,000
May 146:08 PM CDTF0McLean, IL0.110
May 146:12 PM CDTF0Champaign, IL0.110
May 146:45 PM CDTF0Champaign, IL0.110
May 147:14 PM CDTF0Champaign, IL0.110
May 147:19 PM CDTF0Vermilion, IL0.110
May 147:28 PM CDTF0Piatt, IL0.110
May 147:40 PM CDTF0Vermilion, IL0.110
May 148:10 PM CDTF2McCurtain, OK to TX78.3100$250,000
May 148:45 PM ESTF1Boone, IN3.050$50,000

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.