Hail and Damaging Winds in Iowa, July 28, 2002

Name: Hail and Damaging Winds in Iowa, July 28, 2002
Start: 2002-07-28T17:20
End: 2002-07-28T21:00
Location: Iowa

July 28, 2002 · NWS DMX · 12 events in 6 counties and zones

A very unstable airmass was in place over Iowa during the afternoon of the 28th. Surface temperatures were generally in the upper 80s to mid 90s, with dew point temperatures in the 70s to low 80s.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $46,000
Crop damage: $60,000
Events: 12

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS DMX wrote it up.

A very unstable airmass was in place over Iowa during the afternoon of the 28th. Surface temperatures were generally in the upper 80s to mid 90s, with dew point temperatures in the 70s to low 80s. By late afternoon, CAPE values were between 4000 and 6000 J/kg with lifted indices below -10 C. Temperatures aloft were quite warm with 700 mb temperatures around +11 C. This tended to cap convection through the day. A strong MCS tracked across southern Minnesota during the afternoon. The outflow boundary from this system dropped into northwest Iowa during the early evening. Thunderstorms formed along the boundary and produced hail of three quarters of an inch to one inch in diameter during the initiation stage. The severe weather tapered off afer a couple hours. Meanwhile, an area of thunderstorms lifted north out of Missouri. By early evening the intensified as they moved into the more unstable air over Iowa. They became severe for a brief period of time and produced winds of up to 70 MPH, along with one and one quarter inch diameter hail in central Iowa from Warren County, into Marion and Jasper Counties. The storms weakened after that time. A cold front moved across the state during the night, kicking off additional thunderstorms. These storms remained below severe limits.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before the first event at Jul 28, 1:55 PM CST, 3 hours 25 minutes earlier.

Area forecast discussion, Jul 28, 1:55 PM CST, 3 hours 25 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
255 PM CDT SUN JUL 28 2002

MAIN FCST PROB IS WHAT TO DO WITH SVR WX.  CUR THKG IS MOST ACVTY WL
BE N OF IA THO NRN CNTYS MAY BE BRUSHED.  OTR PROB IS WITH THE MSTR
AXIS ALN THE MO BDR.  WL CARRY ISOLD IN THE S THIS EVE, SCT N, THEN
DECENT SHOT N AFT DARK AND NOTHING OVR THE S AND E UNTIL LATE.  KEPT
LKLY POPS IN THE NW AND DROPPED TO CHC ELSW.  CDFNT NOW VRY SIG AND
WL MAKE LTL CHNG IN TEMPS...ABT 3 TO 5 DEG.  DPS WL DROP MON AND TUE
HWVR.  NXT FNT ON SKED LATE WED NGT INTO THU AND ATTM WL OPT TO LV
RST OF FCST DRY.  PERHAPS LATE SUN, BUT PROB IS LO.  FCST BASED
MSTLY ON GEM AND MRF ENS RUNS.

.DSM...NONE
MS JUL 02

The radar

The Sioux Falls radar (KFSD), 163 km away, was scanning. The volume nearest the first event began at 23:18 UTC.

Open the radar archive at this moment

Event by event

7 hail, 5 thunderstorm wind. Local standard time, as filed.

Hail, Palo Alto

When: July 28, 5:20 PM CST
Where: Palo Alto County, Graettinger
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: OTHER FEDERAL AGENCY
Coordinates: 43.233, -94.767

Hail, Emmet

When: July 28, 6:00 PM CST
Where: Emmet County, 2 mi W of Wallingford
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: UNKNOWN
Coordinates: 43.333, -94.867

Hail, Emmet

When: July 28, 6:15 PM CST
Where: Emmet County, 4 mi SE of Wallingford
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: OTHER FEDERAL AGENCY
Coordinates: 43.300, -94.783

Hail, Palo Alto

When: July 28, 6:17 PM CST
Where: Palo Alto County, Graettinger
Measured: 1 in hail
Property damage: $5,000
Crop damage: $10,000
Reported by: BROADCAST MEDIA
Coordinates: 43.233, -94.767

Thunderstorm Wind, Warren

When: July 28, 7:24 PM CST
Where: Warren County, Hartford
Measured: 61 kt (70 mph)
Property damage: $10,000
Crop damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 41.467, -93.417

Thunderstorm Wind, Warren

When: July 28, 7:24 PM CST
Where: Warren County, 4 mi S of Hartford
Measured: 61 kt (70 mph)
Property damage: $5,000
Crop damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 41.417, -93.417

Hail, Marion

When: July 28, 7:25 PM CST
Where: Marion County, Swan
Measured: 1.25 in hail
Property damage: $5,000
Crop damage: $10,000
Reported by: AMATEUR RADIO
Coordinates: 41.467, -93.317

Thunderstorm Wind, Jasper

When: July 28, 7:35 PM CST
Where: Jasper County, 3 mi S of Prairie City
Measured: 61 kt (70 mph)
Property damage: $5,000
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 41.550, -93.233

Hail, Emmet

When: July 28, 7:45 PM CST to 7:47 PM CST
Where: Emmet County, Wallingford
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 43.333, -94.833

Hail, Jasper

When: July 28, 7:54 PM CST
Where: Jasper County, 2 mi E of Colfax
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: LAW ENFORCEMENT
Coordinates: 41.667, -93.217

Thunderstorm Wind, Sac

When: July 28, 8:09 PM CST
Where: Sac County, Schaller
Measured: 52 kt (60 mph)
Property damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 42.500, -95.300

Thunderstorm Wind, Palo Alto

When: July 28, 9:00 PM CST
Where: Palo Alto County, 5 mi S of Cylinder
Measured: 52 kt (60 mph)
Property damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 43.017, -94.567

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 2002 Every state in 2002 This day in weather history Warnings in Iowa, July 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5304702, 5304703, 5304704, 5304705, 5304706, 5304707, 5304708, 5304709, 5304710, 5304711, 5304712, 5304713.