Alert archive / Iowa / Tornado Warnings in 1989

Tornado Warning 1, NWS Sioux Falls, SD

April 27, 1989Plymouth County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Apr 27, 1989, 8:05 PM CDT for Plymouth County, Iowa. It was in force for 25 min.

The area

The counties it named.

The facts

Issued
Apr 27, 1989, 8:05 PM CDT (01:05 UTC)
Expired
Apr 27, 1989, 8:30 PM CDT
In force
25 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, 1.1 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 1989-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 17 joules per kilogram.LCLLFCEL10008507005003002001001 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 1989-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
17 J/kg
Mixed-layer CIN
-176 J/kg
Mixed-layer LCL
3565 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
41 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 280105
TORSUX
IAC149-280130-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING 
NATIONAL WEATHER SERVICE SIOUX CITY IA
805 PM CDT THU APR 27 1989

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 830 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY

   IN THE NORTHWEST PART OF IOWA
      EASTERN PLYMOUTH

AT 755 PM CDT SPOTTERS REPORTED A TORNADO ON THE GROUND 10 MILES
EAST OF MERRILL...20 MILES NORTHEAST OF SIOUX CITY.  THE MOVEMENT
WAS OBSERVED TO THE NORTHEAST AT 25 MILES AN HOUR.  AT THIS
SPEED AND DIRECTION IT COULD MOVE ACROSS REMSEN AND OYENS IOWA...
30 MILES NORTHEAST OF SIOUX CITY...BETWEEN 810 AND 830 PM.

THIS IS A DANGEROUS STORM. TAKE COVER IMMEDIATELY. IF YOU ARE IN A
STRONG BUILDING GO TO AN INTERIOR ROOM ON THE LOWEST FLOOR. AVOID
WINDOWS. ABANDON CARS AND MOBILE HOMES FOR A REINFORCED BUILDING OR
GET INTO A DITCH OR DEPRESSION...COVER YOUR HEAD WITH YOUR HANDS.

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

 RESIDENTS OF MOBILE HOMES SHOULD SEEK A SAFE SHELTER IMMEDIATELY.

SHERLIN

What forecasters said that day

The local office's own words before this tornado 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, Apr 27, 3:57 PM CDT, 4 hours 8 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
400 PM CST THU APR 27 1989

...WINTER STORM WARNING TONIGHT AND FRIDAY NORTHWEST SOUTH DAKOTA
   AND BLACK HILLS...
...SNOW ADVISORY TONIGHT AND WINTER STORM WATCH FRIDAY REMAINDER OF
   THE WEST...

THE NATIONAL WEATHER SERVICE HAS ISSUED A WINTER STORM WARNING FOR
NORTHWEST SOUTH DAKOTA INCLUDING THE BLACK HILLS FOR TONIGHT THROUGH
FRIDAY WITH A SNOW ADVISORY LATE TONIGHT AND WINTER STORM WATCH ON
FRIDAY FOR THE REMAINDER OF THE WEST.

A STRONG AREA OF LOW PRESSURE WILL MOVE SLOWLY EAST ACROSS NEBRASKA
THROUGH FRIDAY AND WILL BRING ABUNDANT MOISTURE FROM THE SOUTH INTO
THE STATE. THIS ABUNDANT MOISTURE COMBINED WITH COLDER AIR MOVING
INTO THE WEST WILL PRODUCE SNOW OVER A LARGE PART OF WESTERN SOUTH
DAKOTA.
<
SNOWFALL AMOUNTS OF 6 TO 12 IN ARE LIKELY OVER THE NORTHWEST THROUGH
FRIDAY WITH ACCUMULATIONS OF MORE THAN A FOOT OVER THE BLACK HILLS.

THE RAIN WILL BE CHANGING SNOW ACROSS THE REMAINDER OF THE WEST
TONIGHT WITH ACCUMULATIONS OF 2 TO 4 INCHES POSSIBLE BY MORNING WITH
HEAVY SNOW POSSIBLE ON FRIDAY.

IN ADDITION TO THE SNOW...STRONG NORTH WINDS WILL BE INCREASING
TO 20 TO 40 MPH AND WILL CREATE NEAR BLIZZARD CONDITIONS OVER A LARGE
PART OF THE WEST.

HISTORICALLY...HEAVY WET SNOWSTORMS ARE NOT UNCOMMON OVER WESTERN
SOUTH DAKOTA AND THE BLACK HILLS IN APRIL. A MAJOR STORM HIT WESTERN
SOUTH DAKOTA IN LATE APRIL OF 1984 WITH OVER 1 FOOT ON THE PLAINS AND
3 TO 6 FEET OF SNOW IN THE BLACK HILLS.

PERSONS ACROSS ALL OF WESTERN SOUTH DAKOTA SHOULD BE PREPARED FOR THIS
MAJOR LATE WINTER STORM. TRAVELLING WILL BECOME EXTREMELY HAZARDOUS
AS THE NIGHT PROGRESSES. IF YOU MUST TRAVEL MAKE SURE YOU BRING ALONG
A WINTER SURVIVAL KIT AND PHONE AHEAD TO LET PEOPLE KNOW YOU ARE
TRAVELLING. DO NOT IGNORE THE WARNING...THIS IS A MAJOR WINTER STORM.

ACROSS THE REMAINDER OF THE STATE...SHOWERS AND THUNDERSTORMS WILL
DEVELOP TONIGHT WITH SEVERE THUNDERSTORMS POSSIBLE SOUTHEAST.
THE SHOWERS AND THUNDERSTORMS WILL CONTINUE ON FRIDAY WITH RAIN
CHANGING TO WET SNOW OVER THE CENTRAL.
Special weather statement, Apr 27, 6:28 PM CDT, 1 hour 37 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
625 PM CDT MON APR 24 1989

...VERY STRONG THUNDERSTORMS MOVING INTO THE SIOUXLAND AREA...

AT 620 PM...RADAR SHOWED VERY STRONG THUNDERSTORMS BEGINNING TO
MOVE INTO NORTHEAST NEBRASKA. A STRONG THUNDERSTORM WAS MOVING
NORTHEAST AT 35 MILES AN HOUR NEAR MASKELL NEBRASKA...ABOUT 35 MILES
NORTHWEST OF SIOUX CITY.

VERY STRONG...POSSIBLY SEVERE THUNDERSTORMS...WILL BE MOVING INTO
NORTHEAST NEBRASKA THIS EVENING AND RESIDENTS OF THIS AREA SHOULD
WATCH WEATHER CONDITIONS CLOSELY.  SHOULD SEVERE WEATHER DEVELOP YOU
SHOULD BE PREPARED TO GO TO A SAFE SHELTER AT A MOMENTS NOTICE.

SHERLIN
Special weather statement, Apr 27, 6:32 PM CDT, 1 hour 33 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
615 PM CDT THU APR 27 1989{{}
...WINTER STORM WARNING TONIGHT AND FRIDAY BLACK HILLS AND FAR
NORTHWEST...
...SNOW ADVISORY LATE TONIGHT AND WINTER STORM WATCH FRIDAY REST OF
WESTERN THIRD...{{}
THE NATIONAL WEATHER SERVICE HAS ISSUED A WINTER STORM WARNING FOR
TONIGHT AND FRIDAY FOR THE BLACK HILLS AND FAR NORTHWEST SOUTH DAKOTA.
OVER THE REST OF THE WESTERN THIRD OF SOUTH DAKOTA A SNOW ADVISORY HAS
BEEN ISSUED FOR LATE TONIGHT WITH A WINTER STORM WATCH FOR FRIDAY{{}.
AT 6 PM CDT A FEW THUNDERSTORMS WITH VERY HEAVY RAIN HAD MOVED INTO
EXTREME SOUTHEAST SOUTH DAKOTA. WET SNOW ALONG WITH SOME RAIN AND SLEET
WAS FALLING OVER WESTERN SOUTH DAKOTA. SCATTERED LIGHT RAIN WAS
FALLING OVER THE CENTRAL. SKIES WERE CLOUDY EAST...EXCEPT PARTS OF THE
EXTREME SOUTHEAST WHICH WERE PARTLY CLOUDY. TEMPERATURES RANGED FROM 32
AT CUSTER TO 64 AT SIOUX FALLS.{{}
THROUGH 8 PM THUNDERSTORMS SHOULD INCREASE IN COVERAGE OVER THE
SOUTHEAST. SOME ACCUMULATION OF WET SNOW WILL BE POSSIBLE OVER THE
WESTERN THIRD OF THE STATE...ESPECIALLY NEAR THE WESTERN SOUTH DAKOTA
BORDER WHERE AN ADDITIONAL INCH OR TWO MAY ACCUMULATE BY 8 PM.
SCATTERED L{IGHT RAIN MAY INCREASE IN THE CENTRAL. TEMPERATURES
WILL FALL A FEW DEGREES.

BIER
Special weather statement, Apr 27, 6:34 PM CDT, 1 hour 31 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
630 PM CST THU APR 27 1989

AT 630 PM CDT SIOUX FALLS RADAR SHOWED INTENSE THUNDERSTORMS WITH VERY
HEAVY RAIN IN NORTHEAST NEBRASKA. THESE STORMS WERE MOVING NORTH
NORTHEAST AT ABUT 30 MPH AND WILL MOVE INTO SOUTH DAKOTA BETWEEN
YANKTON AND VERMILLION BETWEEN 630 AND 7 PM CDT. THESE STORMS MAY
PRODUCE LOCALLY HEAVY RAIN...GUSTY WINDS...AND SMALL HAIL AS THEY
PASS.

OTHER THUNDERSTORMS WITH HEAVY RAIN CONTINUED TO DEVELOP OVER A WIDE
AREA BETWEEN PICKSTOWN AND SIOUX CITY IA. THESE STORMS WILL BE
MOVING NORTH NORTHEAST THROUGH SOUTHEAST SOUTH DAKOTA DURING THE
EVENING HOURS. EVERYONE SHOULD BE PREPARED IN CASE ANY OF THESE
STORMS INTENSIFY.

WILLIAMS
Special weather statement, Apr 27, 7:38 PM CDT, 27 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
737 PM CDT THU APR 27 1989

AT 730 PM CDT...THERE WERE NUMEROUS THUNDERSTORMS...SOME WITH VERY
HEAVY RAIN AND HAIL IN CENTRAL AND SOUTHEAST SOUTH DAKOTA.  THE
STRONGEST THUNDERSTORMS WERE 45 MILES SOUTHWEST OF HURON AND 35 MILES
SOUTHWEST OF SIOUX FALLS.

THUNDERSTORMS WERE ALSO IN NORTHWEST IOWA AND NORTHEAST NEBRASKA.

MOVEMENT WAS NORTH AT 45 MILES AN HOUR IN SOUTHEAST SOUTH DAKOTA
AND NORTHEAST AT 40 MILES AN HOUR IN NORTHEAST NEBRASKA.

A TORNADO WATCH WAS IN EFFECT FROM 730 PM CDT UNTIL 1 AM CDT FOR
EXTREME SOUTHEAST SOUTH DAKOTA.
PRESTON

Nearby

Tornado Warnings in Iowa, 1989Every tornado warning in 1989Tornadoes 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.