F0 tornado, Avery to Highland Center, Iowa, April 30, 2003

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.

Rating

F0

Date

April 30, 2003

Touchdown

6:30 PM CDT (23:30 UTC)

Path length

2.5 miles (4.0 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

Counties

Monroe and Wapello counties

Touchdown point

41.080, -92.700

Lift-off point

41.080, -92.620

Record number

712

A strong storm system moved northeast across Kansas into northern Missouri during the late afternoon and early evening hours. There was a strong contrast across a warm front that extended east from the low. North of the front, afternoon temperatures were in the 50s, while mid 80s were common to the south of the front. In addition, surface dew point temperatures were in the mid 60s in the warm sector. Strong low level winds pushed the warm and moist air over the cold dome to the north of the warm front. During the evening hours. a negatively tilted upper level trough of low pressure lifted northeast across the area. This set the stage for widespread thunderstorm development. With the freezing level relatively low, only 11,000 feet, hail was the most common severe weather reported. There was one tornado that touched down briefly in Monroe and Wapello Counties. A second tornado touched down a short time later northeast of Ottumwa. No significant damage was reported with the tornado. Several of the storms produced hail up to about an inch in diameter. The stronger storms produced hail of golf ball size and larger. The largest hail, baseball size, was reported in Jasper County at Colfax, and also a report of baseball size hail was received from south of Eddyville in Wapello County and north of Avery in Monroe County. There were also several reports of golf ball size hail from around central into southeast Iowa. As the thunderstorms moved through Appanoose County, lightning struck a house in Moulton. The house was set on fire and burned to the ground.

Brief touchdown in open area. Tornado moved into from Monroe County into Wapello County.

Brief touchdown in open area. Tornado moved into county from Monroe County.

Brief touchdown in field.

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

35 minutes of warning. NWS DMX issued a tornado warning for this county at 22:55 UTC, 35 minutes before the tornado touched down, in force until 23:45 UTC.

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 Storm Prediction Center had this point in a Moderate Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:21 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 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.

The Des Moines radar (KDMX), 114 km away, was scanning. The volume nearest the touchdown began at 23:31 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.

The live radar over the trackEvery 2003 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

21 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.