Alert archive / Iowa / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 41, NWS Sioux Falls, SD

July 7, 1987Monona County, Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 7, 1987, 1:07 AM CDT for Monona County, Woodbury County, Iowa. It was in force for 53 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 7, 1987, 1:07 AM CDT (06:07 UTC)
Expired
Jul 7, 1987, 2:00 AM CDT
In force
53 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Monona County, IA, Woodbury County, IA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
Jul 7, 1:20 AM CDTThunderstorm Wind 60Woodbury, IA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 6.1 hours before the alert went out and 105 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1987-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 1987-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 square meters per square second.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.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3581 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KSUX 070607
SVRSUX
IAC149-133-193-070700-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
107 AM CDT TUE JUL 7 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL  200 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN NORTHWEST IOWA
          ...PLYMOUTH
IN WEST CENTRAL IOWA
          ...MONONA...WOODBURY
 
AT 105 AM CDT RADAR INDICATED SEVERE THUNDERSTORMS HAD RAPIDLY FORMED
OVER PLYMOUTH...WOODBURY AND MONONA COUNTIES IN WESTERN IOWA.  THESE
THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 60
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNbING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.
SHERLIN

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Local storm report, Jul 7, 12:22 AM CDT, 45 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT TUE JUL 7 1987

949 PM CDT   PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
             (DAVISON COUNTY)

1007 PM CDT  GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
             (MINNEHAHA COUNTY)

1155 PM CDT  52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
             (CLAY COUNTY)

1217 AM CDT  PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
             SOUTH DAKOTA. (pLINCOLN COUNTY)

JANSEN
Local storm report, Jul 7, 12:23 AM CDT, 44 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 AM CDT TUE JUL 7 1987

949 PM CDT   PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
             (DAVISON COUNTY)

1007 PM CDT  GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
             (MINNEHAHA COUNTY)

1155 PM CDT  52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
             (CLAY COUNTY)

1217 AM CDT  PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
             SOUTH DAKOTA. (qLINCOLN COUNTY)

JANSEN
Special weather statement, Jul 7, 12:45 AM CDT, 22 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
1243 AM CDT TUE JUL 7 1987

...VERU STRONG THUNDERSTORMS MOVING ACROSS UNION COUNTY SOUTH DAKOTA...

AT 1240 AM CDT RADAR INDICATED VERY STRONG THUNDERSTORMS MOVING ACROSS
UNION COUNTY SOUTH DAKOTA...ABOUT 20 TO 45 MILES NORTHWEST OF SIOUX
CITY.  THESE THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.

THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL...HEAVLY RAIN
SHOWER AND STRONG GUSTY WINDS.  RESIDENTS OF UNION COUNTY SOUTH DAKOTA
SHOULD BE ON THE LOOKOUT FOR ANY SEVERE WEATHER AND TAKE SHELTER
IMMEDIATELY IF IT IS OBSERVED.

SHERLIN
Special weather statement, Jul 7, 12:56 AM CDT, 11 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
1255 AM CDT TUE JUL 7 1987

...VERY STRONG THUNDERSTORMS MOVING INTO WESTERN IOWA...

AT 1250 AM CDT RADAR INDICATED A LINE OF VERY STRONG THUNDERSTORMS WAS
MOVING INTO WESTERN IOWA.  THESE STORMS EXTENDED ALL THE WAY FROM THE
EXTREME NORTHWEST CORNER OF IOWA SOUTHWARD INTO MONONA COUNTY...ABOUT
45 MILES SOUTHEAST OF SIOUX CITY.

THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL.  WIND GUSTS
TO AROUND 50 MILES AN HOUR...DANGEROUS LIGHTNING AND HEAVY SHOWERS.
RESIDENTS OF SIOUX...PLYMOUTH...WOODBURY AND MONONA COUNTIES IN WESTERN
IOWA SHOULD BE ON THE LOOKOUT FOR THESE VERY STRONG STORMS AND TAKE
SHTELTER IF SEVERE WEATHER IS OBSERVED.

SHERLIN
Special weather statement, Jul 7, 1:04 AM CDT, 3 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
1250 PM CDT TUE JUL 7 1987

...A THUNDERSTORM WATCH IS IN EFFECT FOR EXTREME SOUTHEAST
SOUTH DAKOTA UNTIL 4AM CDT...

AT 1240 AM CDT...AN INTENSE THUNDERSTORM WITH VERY HEAVY RAIN WAS
IN EXTREME SOUTHEASTERN SOUTH DAKOTA.  THE THUNDERSTORM WAS LOCATED
30 MILES SOUTH OF SIOUX FALLS.  ELSEWHERE INTENSE THUNDERSTORMS WITH
VERY HEAVY RAIN COUNTINUED OVER EASTERN SOUTH DAKOTA AND SOUTHWESTERN
MINNESOTA.  THESE STORMS WERE LOCATED EAST OF THE JAMES RIVER FROM
THE NORTH DAKOTA BORDER TO HURON AND SOUTHEAST OF A LINE FROM HURON
TO MISSION...ABOUT 35 MILES WEST OF WINNER.

MOVEMENT OF ALL STORMS WAS NORTHEAST AT 25 MILES AN HOUR.

LARGE HAIL...DAMAGING WIND...VERY HEAVY RAINS...AND FREQUENT LIGHTNING
ARE POSSIBLE WITH THESE STORMS. IF THREATENING WEATHER APPROACHES YOU
SEEK SHELTER.
HUTCHEON
Special weather statement, Jul 7, 1:06 AM CDT, 1 minute before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
1250 PM CDT TUE JUL 7 1987

...A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR EXTREME SOUTHEAST
SOUTH DAKOTA UNTIL 4AM CDT...

AT 1240 AM CDT...AN INTENSE THUNDERSTORM WITH VERY HEAVY RAIN WAS
IN EXTREME SOUTHEASTERN SOUTH DAKOTA.  THE THUNDERSTORM WAS LOCATED
30 MILES SOUTH OF SIOUX FALLS.  ELSEWHERE INTENSE THUNDERSTORMS WITH
VERY HEAVY RAIN COUNTINUED OVER EASTERN SOUTH DAKOTA AND SOUTHWESTERN
MINNESOTA.  THESE STORMS WERE LOCATED EAST OF THE JAMES RIVER FROM
THE NORTH DAKOTA BORDER TO HURON AND SOUTHEAST OF A LINE FROM HURON
TO MISSION...ABOUT 35 MILES WEST OF WINNER.

MOVEMENT OF ALL STORMS WAS NORTHEAST AT 25 MILES AN HOUR.

LARGE HAIL...DAMAGING WIND...VERY HEAVY RAINS...AND FREQUENT LIGHTNING
ARE POSSIBLE WITH THESE STORMS. IF THREATENING WEATHER APPROACHES YOU
SEEK SHELTER.
HUTCHEON

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 12:33 AM CDTSevere Thunderstorm WarningFSDLyon, Sioux57 min
Jul 7, 1:00 AM CDTSevere Thunderstorm WarningFSDLyon, Osceola, Sioux60 min
Jul 7, 1:07 AM CDTSevere Thunderstorm WarningFSDPlymouth53 min
Jul 7, 1:27 AM CDTSevere Thunderstorm WarningFSDCherokee, O'Brien63 min
Jul 7, 1:46 AM CDTSevere Thunderstorm WarningFSDIda59 min
Jul 7, 2:08 AM CDTSevere Thunderstorm WarningFSDMonona37 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1987Every severe thunderstorm warning in 1987

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.