Alert archive / Iowa / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 187, NWS Sioux Falls, SD

September 20, 1986Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Sep 20, 1986, 7:16 AM CDT for Woodbury County, Iowa. It was in force for 44 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
Sep 20, 1986, 7:16 AM CDT (12:16 UTC)
Expired
Sep 20, 1986, 8:00 AM CDT
In force
44 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County 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
Sep 20, 7:25 AM CDTHail 1.75Woodbury, 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 12:00Z, 0.3 hours before the alert went out and 122 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 12:00Z on 1986-09-20Temperature 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 12:00Z on 1986-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 square meters per square second.193958Sfc1 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
3632 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
179 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 KDSM 201218
SVRSUX
IAC193-201300-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
ISSUED BY DES MOINES IA
716 AM CDT SAT SEP 20 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 800 AM CDT FOR PEOPLE IN THE FOLLOWING
COUNTY OF

NORTHWEST IOWA...WOODBURY

AT 707 AM...GOLF BALL SIZE HAIL WAS REPORTED IN DOWNTOWN
SIOUX CITY.  THE STORM WAS MOVING EAST AROU-ND 25 MILES AN HOUR.

THESE STORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE
OR NO ADVANCE WARNING..SO BE ON THE LOOKOUT AND BE PREPARED TO MOVE
TO A PLACE OF SAFETY IF ONE IS SPOTTED.
/
HAHN

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, Sep 20, 3:54 AM CDT, 3 hours 22 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
350 AM CDT SAT SEP 20 1986

...INTENSE THUNDERSTORMS MOVING INTO EXTREME SOUTHEAST SOUTH DAKOTA...

AT 345 AM CDT RADAR INDICATED A LINE OF INTENSE THUNDERSTORMS MOVING
OUT OF NORTHEAST NEBRASKA INTO EXTREME SOUTHEAST SOUTH DAKOTA. THIS
LINE OF THUNDERSTORMS EXTENDED FROM SIOUX CITY IOWA ALONG THE MISSOURI
RIVER TO 15 MILES NORTHWEST OF YANKTON SOUTH DAKOTA. THE THUNDERSTORMS
WERE MOVING NORTHEAST AT 25 MPH. BRIEF HEAVY RAIN..SMALL HAIL AND STRONG
GUSTY WINDS MAY OCCUR WITH THESE THUNDERSTORMS UNTIL 6 AM CDT. COUNTIES
EFFECTED WOULD BE YANKTON..TURNER..CLAY..LINCOLN..SOUTHERN MINNEHAHA
IN SOUTHEAST SOUTH DAKOTA ALONG WITH SIOUX AND LYON COUNTIES OF
NORTHWEST IOWA AND ROCK COUNTY OF SOUTHWEST MINNESOTA. SOME OF CITIES
MOST LIKELY EFFECTED WOULD BE YANKTON..VERMILLION..LENNOX..PARKER..SIOUX
FALLS IN SOUTH DAKOTA. SIOUX CENTER AND LESTER IN NORTHWEST IOWA AND
LUVERNE IN SOUTHWEST MINNESOTA.
BEHREND
Special weather statement, Sep 20, 4:54 AM CDT, 2 hours 22 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
450 AM CDT SAT SEP 20 1986

...INTENSE THUNDERSTORMS ALONG THE MISSOURI RIVER IN SOUTH CENTRAL
SOUTH DAKOTA...

AT 445 AM CDT RADAR INDICATED AN INTENSE THUNDERSTORM ALONG THE MISSOURI
RIVER IN SOUTHERN CHARLES MIX COUNTY OF SOUTH CENTRAL SOUTH DAKOTA.
THIS INTENSITY THUNDERSTORM WAS 35 MILES WEST OF YANKTON OR 20 MILES
SOUTHEAST OF PICKSTOWN MOVING TO THE EAST NORTHEAST AT 30 MPH. BRIEF
HEAVY RAIN..HAIL AND STRONG GUSTY WINDS MAY OCCUR WITH THE THUNDERSTORM
UNTIL 630 AM CDT AS IT MOVES THROUGH BON HOMME..SOUTHERN HUTCHINSON AND
CLAY CONTIES. SOME OF THE CITIES MOSTLY LIKELY EFFECTED ARE AVON..OLIVET
..SPRINGFIELD..TYNDALL AND YANKTON. ALSO ANYONE CAMPING ALONG THE
MISSOURI RIVER ON LEWIS AND CLARK LAKE SHOULD BE ALERT.
BEHREND
Special weather statement, Sep 20, 6:19 AM CDT, 57 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
615 AM CDT SAT SEP 20 1986

...INTENSE THUNDERSTORM ALONG THE MISSOURI RIVER IN SOUTHEAST SOUTH
DAKOTA...

AT 610 AM CDT RADAR INDICATED AN INTENSE THUNDERSTORM ALONG THE MISSOURI
RIVER IN SOUTHEAST BON HOMME COUNTY OF SOUTHEAST SOUTH DAKOTA. THIS
INTENSITY THUNDERSTORM WAS 15 MILES WEST OF YANKTON IN THE TABOR AREA
MOVING TO THE EAST NORTHEAST AT 30 MPH. BRIEF HEAVY RAIN..SMALL HAIL
AND STRONG GUSTY WINDS MAY OCCUR WITH THE THUNDERSTORM UNTIL 830 AM CDT
AS IT MOVES THROUGH EXTREME EASTERN BON HOMME..YANKTON AND CLAY
COUNTIES. SOME OF THE CITIES MOSTLY LIKELY EFFECTED ARE TABOR..YANKTON
..VOLIN AND VERMILLION. ALSO ANYONE CAMPING ALONG THE MISSOURI RIVER
ON LEWIS AND CLARK LAKE SHOULD BE ALERT.

THE INTENSE THUNDERSTORM WAS PART OF A LARGE AREA OF SHOWERS AND
THUNDERSTORMS THAT WERE OVER MUCH OF SOUTHEAST DAKOTA..NORTHWEST
AND EXTREME SOUTHWEST MINNESOTA.5 SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO CONTINUE TODAY INTO SUNDAY AS A WARM FRONT OVER IOWA
AND NEBRASKA MOVE NORTH THROUGH THE REGION.
BEHREND

Nearby

Severe Thunderstorm Warnings in Iowa, 1986Every severe thunderstorm warning in 1986

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.