Tornadoes · United States · Iowa · 2019

Unrated tornado, Plainview to Donahue, Iowa, July 9, 2019

From Plainview to Donahue, this Unrated tornado ran 0.0 miles across Scott County on July 9, 2019, touching down at 7:41 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 mph

    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. Unratedthis tornado

    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
Unrated
Date
July 9, 2019
Touchdown
7:41 PM CDT (00:41 UTC)
Lifted
7:42 PM CDT (00:42 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.1 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
County
Scott County
Touchdown point
41.668, -90.662
Lift-off point
41.668, -90.662
Record number
1907091841-01

The damage survey

2 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry.

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

Severe thunderstorms moved across eastern Iowa during the early evening. These low topped supercells interacted with a warm front that was draped across eastern Iowa and prodcued two brief tornado touchdowns near Walcott and Donahue. No damage was reported or observed with these touchdowns.

Iowa State Troopers observed a brief tornado near the intersection of 230th Street and 60th Avenue, just north of the I-80 Truckstop in Walcott. The tornado caused no damage from which the National Weather Service could assign an EF-scale rating.

A trained spotter observed a brief tornado in an open field. The tornado caused no damage from which the National Weather Service could assign an EF-scale rating.

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
16:00 UTC19:35 UTCHeat AdvisoryDVN

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 19:55 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.

Davenport, (KDVN), 00:00Z

0.7 hours before the tornado, 14 km from the path. July 10, 2019.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2019-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 802 joules per kilogram, CIN -12, lifted condensation level 1120 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, Davenport, at 00:00Z on 2019-07-10The 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 187 square meters per square second, 0 to 6 km bulk shear 19 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
802 J/kg
Mixed-layer CIN
-12 J/kg
Surface CAPE
3258 J/kg
Mixed-layer LCL
1120 m above ground
0-6 km bulk shear
19 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
280 m²/s²
Significant tornado parameter
0.0
Supercell composite
9.8
0-3 km lapse rate
6.4 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 12:00Z

11.3 hours after it, 14 km from the path. July 10, 2019.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2019-07-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1189 joules per kilogram, CIN -97, lifted condensation level 1187 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, Davenport, at 12:00Z on 2019-07-10The 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 41 square meters per square second, 0 to 6 km bulk shear 24 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
1189 J/kg
Mixed-layer CIN
-97 J/kg
Surface CAPE
1377 J/kg
Mixed-layer LCL
1187 m above ground
0-6 km bulk shear
24 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The surface observations

Quad Cities (DVN), 8 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:45 UTC170° 11 kt1012.5
22:50 UTC160° 11 kt1012.5
22:52 UTC8474160° 11 kt1012.2
22:55 UTC160° 10 kt1012.2
23:00 UTC170° 9 kt1012.2
23:05 UTC170° 10 kt1012.2
23:10 UTC170° 8 kt1012.2
23:15 UTC180° 14 kt1012.2
23:20 UTC 14 kt1012.2
23:25 UTC170° 11 kt1012.2
23:30 UTC170° 11 kt181012.2
23:35 UTC170° 10 kt151012.2
23:40 UTC170° 9 kt1012.2
23:45 UTC160° 10 kt151011.9
23:50 UTC160° 11 kt1011.9
23:52 UTC8372170° 9 kt191011.9
23:55 UTC170° 9 kt
00:00 UTC160° 9 kt1011.9
00:05 UTC160° 13 kt1011.9
00:10 UTC170° 10 kt151011.9
00:12 UTC8372170° 12 kt181011.9VCTS
00:15 UTC170° 9 kt151011.9
00:20 UTC170° 10 kt1011.9
00:25 UTC180° 7 kt1011.9
00:30 UTC170° 8 kt1011.9
00:32 UTC8373170° 7 kt1011.9
00:35 UTC160° 8 kt1011.9
00:40 UTC150° 8 kt1011.9
00:45 UTC160° 11 kt1011.9
00:50 UTC170° 9 kt141011.9
00:52 UTC8373170° 10 kt1011.9
00:55 UTC170° 10 kt1011.9
01:00 UTC180° 11 kt1011.9
01:05 UTC190° 10 kt1011.9
01:10 UTC200° 9 kt1011.9
01:15 UTC200° 11 kt1011.9
01:20 UTC190° 9 kt1011.9
01:25 UTC190° 10 kt1011.9
01:30 UTC190° 10 kt1011.9
01:35 UTC190° 9 kt1012.2
01:40 UTC190° 9 kt1012.2
01:45 UTC190° 8 kt1012.2
01:50 UTC190° 7 kt1012.2
01:52 UTC8273190° 8 kt1012.2
01:55 UTC190° 8 kt1012.2
02:00 UTC190° 7 kt1012.2
02:05 UTC190° 7 kt1012.2
02:10 UTC190° 7 kt1012.2
02:15 UTC190° 8 kt1012.5
02:20 UTC200° 7 kt1012.5
02:25 UTC200° 8 kt1012.5
02:30 UTC190° 7 kt1012.5
02:35 UTC190° 9 kt1012.9
02:40 UTC190° 8 kt1012.9

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

The radar

The Quad Cities radar (KDVN), 9 km away, was scanning. The volume nearest the touchdown began at 00:40 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
22:42 UTCFUNNEL CLOUDCalamusClinton, IAROTATING WALL CLOUD WITH BRIEF FUNNEL EXTENDING HALF WAY TO THE GROUND EAST OF CALAMUS. FEATURE HAS SINCE DISSIPATED.
00:00 UTCHEAVY RAIN 0.34CamancheClinton, IARAINFALL IN 30 MINUTES.
00:05 UTCTORNADO1 W WalcottScott, IASTATE TROOPERS REPORTED A BRIEF TORNADO TOUCHDOWN NEAR WALCOTT AT APPROXIMATELY 7:05 PM. THE FEATURE HAD SINCE DISSIPATED, BUT ROTATION IN THE CLOUDS AS STILL SEEN TO THE NORTH OF WALCOTT.
00:08 UTCFUNNEL CLOUD2 S MassillonCedar, IABRIEF FUNNEL.
00:41 UTCFUNNEL CLOUD3 Sse DonahueScott, IABRIEF FUNNEL CLOUD SEEN TO NORTHWEST OF NWS OFFICE. LASTED LESS THAN 1 MINUTE. LOCATION APPROXIMATE.
00:41 UTCTORNADO2 Sse DonahueScott, IAA TRAINED SPOTTER OBSERVED A BRIEF TORNADO IN AN OPEN FIELD. THE TORNADO CAUSED NO DAMAGE FROM WHICH THE NWS COULD ASSIGN AN EF-SCALE RATING.

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

This ground now

The live radar over the trackEvery 2019 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of July 9, 2019

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 95:19 PM CDTEF1Richland, ND1.5100
July 95:30 PM CDTEF0Richland, ND0.250
July 95:57 PM CDTEF1Wilkin, MN2.0100
July 95:58 PM CDTEF0Clay, MN0.575
July 96:20 PM CDTEF1Wilkin, MN0.9150
July 96:30 PM CDTEF0Clay, MN3.0150
July 96:45 PM CDTEF1Otter Tail, MN2.0150
July 97:08 PM CDTUnratedScott, IA0.110

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.