Damaging Wind in Iowa, June 30, 2001

Name: Damaging Wind in Iowa, June 30, 2001
Start: 2001-06-30T14:34
End: 2001-06-30T14:34
Location: Iowa

June 30, 2001 · NWS DMX · 1 event in 1 county or zone

The airmass over Iowa became quite unstable during the afternoon. Surface temperatures reached the mid 80s to low 90s with dew point temperatures in the 60s.

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

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The toll

Deaths: 0
Injuries: 0
Property damage: $20,000
Crop damage: None recorded
Events: 1

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.

The airmass over Iowa became quite unstable during the afternoon. Surface temperatures reached the mid 80s to low 90s with dew point temperatures in the 60s. CAPE values were in the 2000 to 4000 J/kg range. Thunderstorms fired over northern Iowa during the afternoon along a weak trough that was progressing south across the state. Winds at the 850 mb level were quiet light, in the 5 to 10 kt range, so the storms were more of the pulse variety instead of super cellular. Most of the thunderstorms produced brief gusty winds, pea to marble size hail, and heavy rainfall. A wet microburst occurred in Waterloo with the passage of one of the storms. Damage was reported with numerous trees toppled and some shingle damage in town. Other noteworthy events were in Franklin County, where 5.3 inches of rain fell in a few hours time. Flooding was minimal as the ground was extremely dry from two weeks of light rainfall and warm temperatures. In Sac County, winds of 50 MPH and a little over 2 inches of rain occurred in the Lake View area. Once again, little flooding occurred outside of minor street flooding.

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 Jun 30, 1:40 PM CST, 54 minutes earlier.

Area forecast discussion, Jun 30, 1:40 PM CST, 54 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
240 PM CDT SAT JUN 30 2001

FORECAST CHALLENGES WITH PCPN CHANCES INTO SUNDAY MORNING AND THEN
AGAIN STARTING LATE SUNDAY NIGHT.  TEMPS ALSO TO BE PROBLEMATIC.
TROF INTO NORTHERN IA THIS AFTERNOON WITH MODERATE INSTABILITY.  LOW
LEVEL INFLOW AND SHEAR ARE RELATIVELY WEAK SO WOULD EXPECT PULSE
STORMS WITH BEST CHANCE OF SVR CONVECTION LATE THIS AFTERNOON AND
EVENING WITH REMAINING DAYTIME HEATING.

MODELS AGREE IN MOVING FRONT THROUGH STATE OVERNIGHT WITH STRONG
PUSH OF COOLER AIR.  PCPN TO SLIDE SOUTH THROUGH STATE OVERNIGHT
WITH TSRA/SHRA ENDING N THIS EVENING AND S TOWARD MORNING.  MAY SEE
RESIDUAL PCPN FAR SOUTH ON SUNDAY MORNING...BUT THIS SHOULD END
EARLY AS SUBSIDENCE AND DRIER AIR ADVECT INTO THE STATE.  SOME
CLEARING SHOULD OCCUR ACRS THE EASTERN CWA DURING THE DAY BUT CLDS
TO HANG ON IN THE WEST CLOSER TO STALLING BAROCLINIC ZONE.  SHOULD
BE NOTICEABLY COOLER WITH GUIDANCE DROPPING HIGHS ON SUNDAY 15 TO 20
DEGREES COOLER THAN TODAY.

SUNDAY NIGHT WL SEE WAA RETURN ACRS WESTERN IA LATE.  MOISTURE
ADVECTION AND SHORTWAVE MOVING INTO THE DAKOTAS AND NEBRASKA SHOULD
INITIATE CONVECTION OVER THE PLAINS AND THIS IS EXPECTED TO RIDE
INTO NW IA LATE.  WL RETAIN POPS ACRS THE NORTHWEST THIRD OF CWA FOR
THIS PCPN.  REMAINDER OF THE AREA SHOULD BE QUITE COOL WITH READINGS
DROPPING INTO THE 50S.   MONDAY SHOULD SEE DYING CONVECTION MOVING
ACRS PORTIONS OF THE CWA IN THE MORNING WITH FOCUS THEN SHIFTING
FARTHER WEST AS INSTABILITY AND MOISTURE INCREASE ACRS WESTERN IA.
CHC FOR PCPN WL CONT INTO MONDAY NIGHT AS CONVECTION ACRS THE PLAINS
ONCE AGAIN MOVES INTO THE STATE.  TEMPS TO HOLD BELOW NORMAL FROM
SUNDAY NIGHT ONWARD.

IN THE EXTENDED...FRONTAL BOUNDARY HOLDS NEAR IA THROUGH WED BEFORE
MOVING ON AS STRONG HIGH PRESSURE DROPS SOUTH FROM CANADA.
THEREFORE PCPN CHANCES TO CONTINUE ON TUESDAY AND CENTRAL/SOUTH
WEDNESDAY.  REMAINDER OF EXTENDED TO BE COOL AND DRY WITH HIGH
PRESSURE IN CONTROL.

.DSM...NONE

COGIL

In the hours before

Special weather statement, Jun 30, 1:12 PM CST, 1 hour 22 minutes before

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
212 PM CDT SAT JUN 30 2001

FOR THIS AFTERNOON...A TROUGH OF LOW PRESSURE WILL MOVE ACROSS
CENTRAL IOWA.  SLIGHTLY COOLER AIR ALOFT IS ASSOCIATED WITH
THIS FEATURE.  THE AIRMASS HAS DESTABILIZED ENOUGH TO PERMIT
THUNDERSTORM DEVELOPMENT OVER NORTHERN IOWA.  CAPES OF 2000-4000 EXIST
IN A NARROW RIBBON ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA AND
THERE IS NO CAP TO PROHIBIT CONVECTIVE DEVELOPMENT.  WITH DAYTIME
HEATING COMING TO ITS PEAK TIME THE THUNDERSTORM DEVELOPMENT WILL
BECOME MORE WIDESPREAD BUT THE FLOW FROM THE SURFACE TO 850 MB IS
WEAK SO EXPLOSIVE DEVELOPMENT IN NOT FORECAST.  MOST STORMS WILL NOT
REACH SEVERE LIMITS BUT STORMS THAT DEVELOP NORTH OF HIGHWAY 20 ARE
CLOSEST TO THE GREATEST AREA OF INSTABILITY AND STAND A BETTER
CHANCE TO PRODUCE STRONG WIND AND HAIL.  THE ENVIRONMENT IS SUCH THAT
THOSE STORMS THAT DO HAPPEN TO REACH SEVERE LIMITS WILL BE PULSE
SEVERE IN NATURE AND LIKELY NOT LAST FOR VERY LONG.

DURING THE LATE EVENING OR OVERNIGHT HOURS...A COLD FRONT ACROSS
SOUTHERN SOUTH DAKOTA AND NORTHWEST MINNESOTA WILL PUSH ACROSS
CENTRAL IOWA AND BRING A SECONDARY CHANCE FOR THUNDERSTORMS.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>007-015>017-023>028-033>039-044>050-011100-
BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CERRO
GORDO-CRAWFORD-EMMET-FRANKLIN-GREENE-GRUNDY-HAMILTON-HANCOCK-HARDIN-
HUMBOLDT-KOSSUTH-MARSHALL-PALO
ALTO-POCAHONTAS-SAC-STORY-TAMA-WEBSTER-WINNEBAGO-WORTH-WRIGHT-
INCLUDING THE CITIES OF...ALGONA...AMES...BOONE...CARROLL...
DENISON...ESTHERVILLE...FORT DODGE...IOWA FALLS...MARSHALLTOWN...
MASON CITY...WATERLOO...WAVERLY AND WEBSTER CITY
212 PM CDT SAT JUN 30 2001

* EVENT TIMING...2 PM UNTIL 8 PM AND AGAIN AFTER MIDNIGHT.

* THREAT CATEGORIES...
     TORNADO..........NONE.
     DAMAGING WINDS...LOW.
     LARGE HAIL.......LOW.
     FLASH FLOODING...LOW.

* SPOTTER ACTIVATION OUTLOOK...LOW

* MISCELLANEOUS INFORMATION -  A FEW STORMS MAY REACH SEVERE LIMITS
THIS AFTERNOON BUT WIDESPREAD SEVERE STORMS ARE NOT EXPECTED.  THE
PRIMARY THREAT FROM THE STORMS WOULD BE STRONG WIND AND HAIL BUT DUE
TO THE SLOW MOVEMENT OF THE STORMS...ISOLATED AREAS OF HEAVY RAIN
MAY ALSO OCCUR.

IAZ057>062-070>075-081>086-092>097-011100-
ADAIR-ADAMS-APPANOOSE-AUDUBON-CASS-CLARKE-DALLAS-DAVIS-DECATUR-
GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-MONROE-POLK-POWESHIEK-
RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN-WAYNE-
INCLUDING THE CITIES OF...ATLANTIC...CENTERVILLE...CHARITON...
CRESTON...DES MOINES...GRINNELL...INDIANOLA...KNOXVILLE...LAMONI...
NEWTON...OSKALOOSA...OTTUMWA...PELLA AND PERRY
212 PM CDT SAT JUN 30 2001

* EVENT TIMING...4 PM UNTIL 9 PM AND AGAIN AFTER MIDNIGHT.

* THREAT CATEGORIES...
     TORNADO..........NONE.
     DAMAGING WINDS...NONE.
     LARGE HAIL.......NONE.
     FLASH FLOODING...NONE.

* SPOTTER ACTIVATION OUTLOOK...NOT EXPECTED.

* MISCELLANEOUS INFORMATION - THUNDERSTORMS WILL DEVELOP IN THE AREA
BY 4 PM AND INCREASE IN COVERAGE THROUGH THE AFTERNOON BUT ARE NOT
EXPECTED TO BECOME SEVERE.  GUSTY WIND AND SMALL HAIL IS POSSIBLE
WITH A FEW STORMS.

FAB
-------------------------------------------------------------------

THREAT KEY:
    TORNADO.......... ANY TORNADO OCCURRENCE
    DAMAGING WINDS... WINDS >= 58 MPH
    LARGE HAIL....... HAIL >= 3/4 INCH DIAMETER
    FLASH FLOODING... FLOODING CAUSED BY HEAVY RAINS WITHIN 6 HOURS
                      OF RAIN EVENT. POSES THREAT TO LIFE OR
                      PROPERTY.

THREAT CATEGORY KEY:  PROBABILITY OF THREAT OCCURRING WITHIN 25
                      MILES OF POINT WITHIN FORECAST AREA
    NONE....... NOT EXPECTED.  LESS THAN 5% ( 2% FOR TORNADOES)
    LOW........ 5-15% (2-15% FOR TORNADOES)
    MODERATE... 25-35%
    HIGH....... 45% OR GREATER

SPOTTER ACTIVATION OUTLOOK KEY:
    NOT EXPECTED
    LOW........ ACTIVATION POSSIBLE BUT NOT LIKELY
    MODERATE... POSSIBILITIES ABOUT 50-50
    HIGH....... ACTIVATION LIKELY

FOR MORE INFORMATION ON PROBABILISTIC SEVERE WEATHER OUTLOOKS...GO
TO THE STORM PREDICTION CENTER WEBSITE AT
WWW.SPC.NOAA.GOV/PRODUCTS/OUTLOOK/PROBINFO.HTML .

FAB

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 thunderstorm wind. Local standard time, as filed.

Thunderstorm Wind, Black Hawk

When: June 30, 2:34 PM CST
Where: Black Hawk County, Waterloo
Measured: 54 kt (62 mph)
Property damage: $20,000
Reported by: BROADCAST MEDIA
Coordinates: 42.500, -92.350

What these are

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 2001 Every state in 2001 This day in weather history Warnings in Iowa, June 2001

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: 5246837.