Hail in Iowa, May 27, 2001

Name: Hail in Iowa, May 27, 2001
Start: 2001-05-27T18:47
End: 2001-05-27T19:15
Location: Iowa

May 27, 2001 · NWS DMX · 3 events in 1 county or zone

A fairly strong convergence zone had become established over western Iowa during the afternoon. A warm front extended from south central South Dakota, southeast into southwest Iowa.

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: $2,000
Crop damage: $15,000
Events: 3

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 fairly strong convergence zone had become established over western Iowa during the afternoon. A warm front extended from south central South Dakota, southeast into southwest Iowa. A weak upper level system moved southeast along the front. During the maximum heating of the day, CAPE values rose to around 1000 J/kg and surface dew point temperatures rose into the mid 50s to near 60. There was a fair contrast across the front with temperatures on the cold side of the warm front in the mid to upper 60s with a light northeast wind, and readings in the low 80s with a light southwest wind to the southwest of the front. All in all, conditions were marginal with a weak wind profile in place. Thunderstorms formed along the warm front. With freezing levels just below 10000 feet AGL, many of the storms produced small hail. One of the storms produced hail around three quarters of an inch to a little larger over Cass County from around Anita to about half way to Massena. The storm did not produce severe size hail for more than 15 to 20 minutes before it weakened.

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 May 27, 1:47 PM CST, 5 hours earlier.

Area forecast discussion, May 27, 1:47 PM CST, 5 hours before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
247 PM CDT SUN MAY 27 2001

FORECAST CHALLENGES CONTINUE WITH PCPN CHANCES.  CURRENTLY...STILL UNDER
THE INFLUENCE OF LARGE UPPER LOW THAT PLAGUED THE STATE THIS PAST
WEEK.  ALTHOUGH WE WILL NOT SEE THE COVERAGE OF SHOWERS THIS
AFTERNOON THAT WE HAVE SEEN LATELY...WL STILL HAVE WDLY SCT SHOWERS
ALONG AXIS OF WEAK LIFT SLIDING SOUTH FROM MINNESOTA.  MOST OF THESE
SHOULD DISSIPATE THIS EVENING AS HEATING SUBSIDES.

MODELS GENERALLY SIMILAR THROUGH 48 HRS WITH SOME DISAGREEMENT IN
TIMING THEREAFTER.  WEAK BAROCLINIC ZONE NEAR W IA OVERNIGHT WITH
FINAL SHORTWAVE MOVING THROUGH.  MODELS INDICATE MARGINAL
INSTABILITY AND MAY SEE SOME SHRA OVERNIGHT IN W HALF CWA AS WAVE
PASSES.  RIDGE AXIS THEN BUILDS INTO THE STATE FOR MONDAY AS
BAROCLINIC ZONES AND PCPN SHIFTS FARTHER SW.  AVN DEVELOPS PCPN
ALONG SECONDARY ZONE NEAR NE/IA BORDER LATE MONDAY.  FEEL PRIMARY
FOCUS FOR SHRA/TSRA SHOULD REMAIN FARTHER SW IN NE/KS/OK WHERE
THETA-E ADVECTION STRONGEST ALONG WITH PRIMARY SFC BOUNDARY.
ALTHOUGH AN ISOLATED SHRA MAY STILL OCCUR FAR W...WL LEAVE IT A
SILENT 20.

RIDGING HOLDS MONDAY NIGHT INTO EARLY TUESDAY ACRS MUCH OF THE CWA.
WL SEE WINDS SHIFT TO SE ON TUESDAY WITH MOISTURE ADVECTION
INCREASING LATER IN THE DAY. HAVE OPTED TO KEEP CHC OUT ON TUESDAY
AND WL PUSH BACK TO TUESDAY NIGHT AS CONVECTION IN NEBRASKA
APPROACHES THE STATE.  IN THE EXTENDED...THE FRONT TO NEAR IA ON WED
WITH SHRA/TSRA EXPECTED.  SOME MORNING SHRA ON THURSDAY AS FRONT
MOVES EAST AND ANOTHER CHC FOR SHRA ON FRIDAY...ESPECIALLY EAST AS
UPPER LOW PASSES THROUGH.  RIDGING TO BUILD IN NEXT WEEKEND AND WL
LEAVE IT A DRY FORECAST FOR NOW.

.DSM...NONE

COGIL

In the hours before

Special weather statement, May 27, 4:28 PM CST, 2 hours 19 minutes before

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
528 PM CDT SUN MAY 27 2001

LOW PRESSURE IN SOUTH DAKOTA WILL SLIDE SOUTHEAST ALONG A WARM FRONT
WHICH EXTENDS FROM THE LOW INTO SOUTHWEST IOWA.  THE LOW WILL PASS
TO THE SOUTHEAST OF THE AREA LATER TONIGHT FOLLOWED BY BUILDING HIGH
PRESSURE.  THUNDERSTORMS HAVE FORMED JUST AHEAD OF THE LOW PRESSURE
AND WARM FRONT.  THESE WILL BE WITH US THROUGH THE EVENING.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>007-015>017-023>028-035>039-047>050-061-062-074-075-085-086-
096-097-281100-
APPANOOSE-BLACK HAWK-BOONE-BREMER-BUTLER-CERRO
GORDO-DAVIS-EMMET-FRANKLIN-GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POWESHIEK-STORY-TAMA-WAPELLO-WEBSTER-WINNEBAGO-WORTH-
WRIGHT-
INCLUDING THE CITIES OF...ALGONA...AMES...BOONE...CENTERVILLE...
ESTHERVILLE...FORT DODGE...GRINNELL...IOWA FALLS...KNOXVILLE...
MARSHALLTOWN...MASON CITY...NEWTON...OSKALOOSA...OTTUMWA...PELLA...
WATERLOO...WAVERLY AND WEBSTER CITY
528 PM CDT SUN MAY 27 2001

* EVENT TIMING... THROUGH THIS EVENING UNTIL MIDNIGHT

* THREAT CATEGORIES...
     TORNADO.......... NOT EXPECTED
     DAMAGING WINDS... NOT EXPECTED
     LARGE HAIL....... NOT EXPECTED
     FLASH FLOODING... NOT EXPECTED

* SPOTTER ACTIVATION OUTLOOK... NOT EXPECTED

IAZ033-034-044>046-057>060-070>073-081>084-092>095-281100-
ADAIR-ADAMS-AUDUBON-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-
DECATUR-GREENE-GUTHRIE-LUCAS-MADISON-POLK-RINGGOLD-SAC-TAYLOR-UNION-
WARREN-WAYNE-
INCLUDING THE CITIES OF...ATLANTIC...CARROLL...CHARITON...CRESTON...
DENISON...DES MOINES...INDIANOLA...LAMONI AND PERRY
528 PM CDT SUN MAY 27 2001

* EVENT TIMING... THIS EVENING THROUGH 100 AM

* THREAT CATEGORIES...
     TORNADO.......... NOT EXPECTED
     DAMAGING WINDS... LOW
     LARGE HAIL....... LOW
     FLASH FLOODING... NOT EXPECTED

* SPOTTER ACTIVATION OUTLOOK...LOW

* MISCELLANEOUS INFORMATION - THUNDERSTORMS WILL TEND TO BE QUIET
ISOLATED AND LOT LAST VERY LONG.  THE GREATEST POTENTIAL WITH THE
STORMS WILL BE FOR HAIL.

-------------------------------------------------------------------

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 AT4
WWW.SPC.NOAA.GOV/PRODUCTS/OUTLOOK/PROBINFO.HTML .

MS MAY 01

Special weather statement, May 27, 5:28 PM CST, 1 hour 19 minutes before

CENTRAL IOWA THUNDERSTORM OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE DES MOINES IA
628 PM CDT SUN MAY 27 2001

LOW PRESSURE IN SOUTH DAKOTA WILL SLIDE SOUTHEAST ALONG A WARM FRONT
WHICH EXTENDS FROM THE LOW INTO SOUTHWEST IOWA.  THE LOW WILL PASS
TO THE SOUTHEAST OF THE AREA LATER TONIGHT FOLLOWED BY BUILDING HIGH
PRESSURE.  THUNDERSTORMS HAVE FORMED JUST AHEAD OF THE LOW PRESSURE
AND WARM FRONT.  THESE WILL BE WITH US THROUGH THE EVENING.

SEE SITE SPECIFIC DETAILS BELOW FOR MORE INFORMATION.

IAZ004>007-015>017-023>028-035>039-047>050-061-062-074-075-085-086-
096-097-281100-
APPANOOSE-BLACK HAWK-BOONE-BREMER-BUTLER-CERRO
GORDO-DAVIS-EMMET-FRANKLIN-GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POWESHIEK-STORY-TAMA-WAPELLO-WEBSTER-WINNEBAGO-WORTH-
WRIGHT-
INCLUDING THE CITIES OF...ALGONA...AMES...BOONE...CENTERVILLE...
ESTHERVILLE...FORT DODGE...GRINNELL...IOWA FALLS...KNOXVILLE...
MARSHALLTOWN...MASON CITY...NEWTON...OSKALOOSA...OTTUMWA...PELLA...
WATERLOO...WAVERLY AND WEBSTER CITY
528 PM CDT SUN MAY 27 2001

* EVENT TIMING... THIS EVENING THROUGH MIDNIGHT

* THREAT CATEGORIES...
     TORNADO.......... NOT EXPECTED
     DAMAGING WINDS... NOT EXPECTED
     LARGE HAIL....... NOT EXPECTED
     FLASH FLOODING... NOT EXPECTED

* SPOTTER ACTIVATION OUTLOOK... NOT EXPECTED

IAZ033-034-044>046-057>060-070>073-081>084-092>095-281100-
ADAIR-ADAMS-AUDUBON-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-
DECATUR-GREENE-GUTHRIE-LUCAS-MADISON-POLK-RINGGOLD-SAC-TAYLOR-UNION-
WARREN-WAYNE-
INCLUDING THE CITIES OF...ATLANTIC...CARROLL...CHARITON...CRESTON...
DENISON...DES MOINES...INDIANOLA...LAMONI AND PERRY
528 PM CDT SUN MAY 27 2001

* EVENT TIMING... THIS EVENING THROUGH 100 AM

* THREAT CATEGORIES...
     TORNADO.......... NOT EXPECTED
     DAMAGING WINDS... LOW
     LARGE HAIL....... LOW
     FLASH FLOODING... NOT EXPECTED

* SPOTTER ACTIVATION OUTLOOK...LOW

* MISCELLANEOUS INFORMATION - THUNDERSTORMS WILL TEND TO BE QUITE
ISOLATED AND NOT LAST VERY LONG.  THE GREATEST POTENTIAL WITH THE
STORMS WILL BE FOR HAIL.

-------------------------------------------------------------------

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 .

MS/FAB MAY 01

The radar

The Des Moines radar (KDMX), 92 km away, was scanning. The volume nearest the first event began at 00:49 UTC.

Open the radar archive at this moment

Event by event

3 hail. Local standard time, as filed.

Hail, Cass

When: May 27, 6:47 PM CST
Where: Cass County, Anita
Measured: 0.88 in hail
Property damage: $2,000
Crop damage: $5,000
Reported by: BROADCAST MEDIA
Coordinates: 41.450, -94.767

Hail, Cass

When: May 27, 7:02 PM CST
Where: Cass County, 4 mi S of Anita
Measured: 0.75 in hail
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 41.400, -94.767

Hail, Cass

When: May 27, 7:15 PM CST
Where: Cass County, 6 mi S of Anita
Measured: 0.88 in hail
Crop damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 41.367, -94.767

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

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, May 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: 5242520, 5242518, 5242519.