Alert archive / Iowa / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 71, NWS Sioux Falls, SD

August 5, 1989Plymouth County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 5, 1989, 6:45 AM CDT for Plymouth County, Iowa. It was in force for 60 min.

The area

The counties it named.

The facts

Issued
Aug 5, 1989, 6:45 AM CDT (11:45 UTC)
Expired
Aug 5, 1989, 7:45 AM CDT
In force
60 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Plymouth 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, 11.8 hours before the alert went out and 158 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 1989-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 31 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 1989-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 square meters per square second.19395878Sfc1 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
31 J/kg
Mixed-layer CIN
-246 J/kg
Mixed-layer LCL
3581 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
90 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 051145
SVRSUX
IAC149-193-NEC043-173-051245-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE SIOUX CITY IA
645 AM CDT SAT AUG 5 1989

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 745 AM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES

   IN THE NORTHWEST PART OF IOWA
      PLYMOUTH...

   IN THE WEST CENTRAL PART OF IOWA
      WOODBURY...

   IN THE NORTHEAST PART OF NEBRASKA
      DAKOTA...THURSTON...

AT 640 AM RADAR INDICATED AN AREA OF SEVERE THUNDERSTORMS FROM
NEAR JEFFERSON SOUTH DAKOTA...10 MILES NORTHWEST OF SIOUX CITY
TO 35 MILES WEST OF SIOUX CITY.  THESE STORMS WERE MOVING EAST
AT 35 MPH.

REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE DAMAGING WINDS IN EXCESS
OF 60 MPH...LARGE HAIL...DEADLY LIGHTNING...AND HEAVY RAINS THAT CAN
QUICKLY FLOOD LOW LYING AREAS. IF YOU ARE IN THE PATH OF THIS STORM
TAKE SHELTER IN A REINFORCED BUILDING IMMEDIATELY.

ASK THE NEAREST LAW ENFORCEMENT AGENCY TO RELAY YOUR REPORTS
OF SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE.

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, Aug 5, 4:04 AM CDT, 2 hours 41 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
400 AM CDT AUG 05 1989

...STRONG THUNDERSTORM OVER NORTHERN UNION COUNTY SOUTH DAKOTA AND
SIOUX COUNTY IOWA...

AT 355 AM CDT RADAR SHOWED THAT A VERY STRONG THUNDERSTORMS HAD FORMED
FROM 30 TO 40 MILES NORTH TO NORTHWEST OF SIOUX CITY...OVER NORTHERN
UNION COUNTY SOUTH DAKOTA AND SOUTHWEST SIOUX COUNTY IOWA.  MOVEMENT
WAS EAST AT 25 MILES AN HOUR.  THIS DIRECTION AND SPEED WILL TAKE
THESE STORMS OVER THE TOWNS OF ALCESTER AND BIG SPRINGS IN UNION COUNTY
AND HAWARDEN...CHATSWORTH...MAURICE...ORANGE CITY AND ALTON IN
SIOUX  COUNTY IOWA...BETWEEN 400 AND 500 AM.

THESE STORMS HAVE THE POTENTIAL FOR SMALL HAIL...HEAVY RAIN SHOW*ERS...
DANGEROUS LIGHTNING AND STRONG GUSTY WINDS.  RESIDENTS OF THE UNION
AND PLYMOUTH COUNTY AREA SHOULD WATCH THE WEATHER CLOSELY AND BE
PREPARED TO GO TO A SAFE SHELTER IF SEVERE WEATHER SHOULD DEVELOPE.
SHERLIN
Special weather statement, Aug 5, 4:09 AM CDT, 2 hours 36 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
410 AM CDT SAT AUG 5 1989

AT 405 AM CDT A THUNDERSTORM WITH VERY HEAVY RAIN AND HAIL LOCATED
38 MILES SOUTH SOUTHEAST OF SIOUX FALLS IN SOUTHWEST SIOUX COUNTY
WAS MOVING TO THE EAST AT 35 MPH.

THIS STORM IS EXPECTED TO REACH SIOUX CENTER IOWA AROUND 415 AM
CDT AND ALTON IOWA AROUND 430 AS IT TRACKS EASTWARD ACROSS
SIOUX COUNTY. RESIDENTS OF SIOUX COUNTY...ESPECIALLY THE S2OUTHERN
TWO THIRDS OF SIOUX COUNTY SHOULD BE ALERT TO THE POSSIBILITY OF
STRONG GUSTY WINDS AND HAIL AS THIS THUNDERSTORM MOVES THROUGH.

BIER
Special weather statement, Aug 5, 4:15 AM CDT, 2 hours 30 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
400 AM CDT AUG 05 1989

...STRONG THUNDERSTORM OVER NORTHERN UNION COUNTY SOUTH DAKOTA AND
SIOUX COUNTY IOWA...

AT 355 AM CDT RADAR SHOWED THAT A VERY STRONG THUNDERSTORMS HAD FORMED
FROM 30 TO 40 MILES NORTH TO NORTHWEST OF SIOUX CITY...OVER NORTHERN
UNION COUNTY SOUTH DAKOTA AND SOUTHWEST SIOUX COUNTY IOWA.  MOVEMENT
WAS EAST AT 25 MILES AN HOUR.  THIS DIRECTION AND SPEED WILL TAKE
THESE STORMS OVER THE TOWNS OF ALCESTER AND BIG SPRINGS IN UNION COUNTY
AND HAWARDEN...CHATSWORTH...MAURICE...ORANGE CITY AND ALTON IN
SIOUX  COUNTY IOWA...BETWEEN 400 AND 500 AM.

THESE STORMS HAVE THE POTENTIAL FOR SMALL HAIL...HEAVY RAIN SHOWERS...
DANGEROUS LIGHTNING AND STRONG GUSTY WINDS.  RESIDENTS OF THE UNION
AND SIOUX  COUNTY AREA SHOULD WATCH THE WEATHER CLOSELY AND BE
PREPARED TO GO TO A SAFE SHELTER IF SEVERE WEATHER SHOULD DEVELOPE.
SHERLIN ....CORRECTION TO LAST PARA...<SIOUX COUNTRY REPLACES PLYMOUTH...
Special weather statement, Aug 5, 5:29 AM CDT, 1 hour 16 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
527 AM CDT AUG 05 1989

...VERY STRONG THUNDERSTORMS MOVING OVER OBRIEN COUNTY IOWA...

AT 525 AM CDT RADAR SHOWED THAT A VERY STRONG THUNDERSTORMS FROM NEAR
PAULINA TO HARTLY IOWA...50 TO 60 MILES NORTHEAST OF SIOUX CITY.  THESE
STORMS WERE MOVING EAST AT 35 MILES AN HOUR AND WILL PASS ACROSS PAULINA
PRINGHAR...HARTLEY AND SUTHERLAND BETWEEN 525 AND 630 AM CDT.

AT 522 AM THE SHERIFFS OFFICE IN PRIMGHAR REPORTED WINDS EASTIMATED
AT 35 TO 40 MILES AN HOUR NEAR ARCHER...55 MILES NORTHEAST OF
SIOUX CITY...AND A BRIEF PERIOD OF PEA SIZE HAIL JUST WEST OF PRIMGHAR...
ABOUT 60 MILES NORTHEAST OF SIOUX CITY.

RESIDENTS OF THE EASTERN HALF OF OBRIEN COUNTY SHOULD WATCH WEATHER
CONDITIONS CLOSELY AND BE PREPARED TO GO TO A SAFE SHELTER IF SEVERE
WEATHER SHOULD DEVELOP.
SHERLIN

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 4:20 AM CDTSevere Thunderstorm WarningFSDSioux25 min
Aug 5, 4:49 AM CDTSevere Thunderstorm WarningFSDPlymouth56 min
Aug 5, 4:49 AM CDTSevere Thunderstorm WarningFSDSioux26 min
Aug 5, 6:45 AM CDTSevere Thunderstorm WarningFSDWoodbury60 min
Aug 5, 6:55 AM CDTSevere Thunderstorm WarningFSDMonona65 min
Aug 5, 7:35 AM CDTSevere Thunderstorm WarningFSDIda55 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1989Every severe thunderstorm warning in 1989

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.