Alert archive / Iowa / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 45, NWS Sioux Falls, SD

July 7, 1987Monona County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 7, 1987, 2:08 AM CDT for Monona County, Iowa. It was in force for 37 min.

The area

The counties it named.

The facts

Issued
Jul 7, 1987, 2:08 AM CDT (07:08 UTC)
Expired
Jul 7, 1987, 2:45 AM CDT
In force
37 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Monona County, IA

The radar

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

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 7.1 hours before the alert went out and 88 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 070708
SVRSUX
IAC133-070745-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
208 AM CDT TUE JUL 7 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL  245 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN WEST CENTRAL IOWA
          ...EASTERN MONONA
 
AT 208 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM OVER EASTERN
MONONA COUNTY NEAR SOLDIER IOWA...ABOUT 48 MILES SOUTHEAST OF SIOUX
CITY. THE STORM WAS MOVING NORTHEAST AT 30 MILES AN HOUR.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DON'T USE TELEPHONES
OR ELECTRICAL APPLIANCES UNLESS IN AN EMERGENCY UNTIL THE STORM
HAS PASSED.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.
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

Special weather statement, Jul 7, 1:06 AM CDT, 1 hour 2 minutes 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
Local storm report, Jul 7, 1:43 AM CDT, 25 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
145 PM CDT TUE JUL 7 1987

1230 AM CDT  RADIO STATION KVDB IN SIOUX CENTER IOWA(SIOUX COUNTY)
             REPORTED POWER LINES DOWN IN HAYWARDEN IOWA.

1259 AM CDT  RADIO STATION KVDB IN SIOUX CENTER IOWA(SIOUX COUNTY)
             REPORTED A WIND GUST TO 67 MPH.

115 AM CDT   HAIL COVERING THE GROUND AT SIOUX CENTER IOWA.
             SIZE UNKNOWN. REPORT RECIEVED FROM STATION KVDB.

JANSEN
Special weather statement, Jul 7, 1:43 AM CDT, 25 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
145 AM CDT TUE JUL 7 1987

...SEVERE THUNDERSTORM WATCH NUMBER 333 WAS CANCELED FOR SOUTHEAST
SOUTH DAKOTA...

THE NATIONAL WEATHER SERVICE HAS CANCELED THE SOUTH DAKOTA PORTION
OF SEVERE THUNDERSTORM WATCH NUMBER 333.

SCATTERED THUNDERSTORMS CONTINUED IN SOUTHEAST SOUTH DAKOTA...BUT
SEVERE THUNDERSTORMS ARE NOW UNLIKELY.

THE SEVERE THUNDERSTORMS WATCH REMAINS IN EFFECT AS EARLIER ISSUED
IN THE ADJOINING AREAS OF SOUTHWEST MINNESOTA...NORTHWEST IOWA...
AND NORTHEAST NEBRASKA.

UMLAND
Local storm report, Jul 7, 1:59 AM CDT, 9 minutes before
STORM REPORT  ... CORRECTION ...
NATIONAL WEATHER SERVICE SIOUX FALLS SD
155 AM CDT TUE JUL 7 1987

1230 AM CDT  RADIO STATION KVDB IN SIOUX CENTER IOWA IN SIOUX COUNTY.
             REPORTED POWER LINES DOWN IN HAYWARDEN IOWA.

1259 AM CDT  RADIO STATION KVDB IN SIOUX CENTER IOWA IN SIOUX COUNTY.
             REPORTED A WIND GUST TO 67 MPH. SEVERAL TREES DOWN AND
             ROADS BLOCKED.

115 AM CDT   HAIL COVERING THE GROUND AT ROCK VALLEY IOWA IN SIOUX
             COUNTY...SIZE UNKNOWN. 2 INCHES OF RAIN. REPORTED BY KVDB
             IN SIOUX CENTER IOWA.

BEHREND
Special weather statement, Jul 7, 2:01 AM CDT, 7 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
150 PM CDT TUE JUL 7 1987

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

AT 135 AM CDT...AN INTENSE THUNDERSTORM HAD MOVED INTO EXTREME
NORTHWESTERN IOWA.  IN SOUTH DAKOTA A THUNDERSTORM WITH VERY HEAVY RAIN
WAS LOCATED 15 MILEA NORTHEAST OF WATERTOWN...OTHERWISE THUNDERSTORMS
WITH HEAVY RAIN AT TIMES WERE LOCATED IN EASTERN SOUTH DAKOTA AND
SOUTHWESTERN MINNESOTA.  MOST OF THE THUNDERSTORMS WERE LOCATED
EAST OF THE JAMES RIVER.

MOVEMENT OF ALL STORMS WAS NORTHEAST AT 25 MILES AN HOUR.
THE STORMS AREAL COVERAGE AND INTENSITIES WERE SHOWING A SLIGHT
DECREASE OVER THE PAST HOUR.

HUTCHEON
Special weather statement, Jul 7, 2:03 AM CDT, 5 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
202 AM CDT TUE JUL 7 1987

...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 4 AM CDT FOR NORTHWEST
IOWA AND SOUTHWEST MINNESOTA BUT NO LONGER IN EFFECT FOR SOUTHEAST
SOUTH DAKOTA...

AT 155 AM CDT RADAR INDICATED INTENSE THUNDERSTORMS JUST EAST OF
WORTHINGTON MINNESOTA IN EASTERN NOBLES COUNTY AND IN WESTERN
OSCEOLA COUNTY OF NORTHWEST IOWA NEAR ASHTON IOWA.

THESE STORMS ARE STILL CAPABLE OF PRODUCING SMALL HAIL...GUSTY WINDS
AND HEAVY RAINS AS THEY MOVE EAST AT 25 MPH.

OTHERWISE SCATTERED SHOWERS AND THUNDERSTORMS CONTINUED OVER EXTREME
EASTERN SOUTH DAKOTA...NORTHWEST IOWA AND SOUTHWEST MINNESOTA.
THE PRECIPITATION WAS GENERALLY EAST OF A LINE FROM NEAR WATERTOWN
SOUTH DAKOTA...SOUTHWEST TO NEAR SALEM TO JUST EAST OF YANKTON
SOUTH DAKOTA.
JANSEN

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 WarningFSDMonona, Woodbury53 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

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; the sounding from the Mesonet's radiosonde archive.