Alert archive / Iowa / Severe Thunderstorm Warnings in 1986

Severe Thunderstorm Warning 53, NWS Sioux Falls, SD

June 20, 1986Lyon County, Osceola County, Sioux County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 20, 1986, 2:41 PM CDT for Lyon County, Osceola County, Sioux County, Iowa. It was in force for 64 min.

The area

The counties it named.

The facts

Issued
Jun 20, 1986, 2:41 PM CDT (19:41 UTC)
Expired
Jun 20, 1986, 3:45 PM CDT
In force
64 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Lyon County, IA, Osceola County, IA, Sioux 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 12:00Z, 7.7 hours before the alert went out and 220 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 1986-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 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 1986-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -66 square meters per square second.1939Sfc1 km3 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
3626 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-66 m²/s²
0-3 km storm-relative helicity
-49 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 KFSD 201941
SVRFSD
IAC119-143-167-202045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
241 PM CDT FRI JUN 20 1986

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 345 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTIES OF

NORTHWEST IOWA...EASTERN LYON...WESTERN OSCEOLA AND EASTERN SIOUX

SOME OF THE CITIES INCLUDED IN ORANGE CITY..SIBLEY..GEORGE..AND
ALTON IN IOWA.

AT 240 PM CDT  RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS
FROM 40 MILES SOUTHEAST OF SIOUX FALLS TO 25 MILES SOUTHEAST OF
SIOUX FALL SD. BETWEEN THE CITIES OF ALTON AND GEORGE IOWA.

 ***  REPORTED INFORMATION  ***
AT 210 PM CDT 71 MPH WINDS WERE OBSERVED AT IRETON IOWA.

IF YOU ARE IN THE PATH OF THIS STORM..YOU SHOULD GET TO A REINFORCED
SHELTER. A SEVERE THUNDERSTORM PRODUCES DAMAGING WINDS IN EXCESS OF
60 MPH..HAIL 3/4 INCH OR LARGER..DEADLY LIGHTNING..AND HEAVY RAINp
THAT CAN QUICKLY FLOOD A LOW LYING AREA.

UMLAND

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, Jun 20, 12:19 PM CDT, 2 hours 22 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE HURON SD
Local storm report, Jun 20, 12:29 PM CDT, 2 hours 12 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE HURON SD
1220 PM CDT FRI JUN 20 1986

BETWEEN 600 AM CDT AND 730 AM CDT 4 1/2 INCHES OF RAIN WAS REPORTED
IN SOUTHERN HAND COUNTY...WASHED OUT A BRIDGE ON AMESTORE ROAD 17 MILES
SOUTH AND 1 MILE WEST OF MILLER, SD.

ANOTHER REPORT IN SOUTHERN HAND COUNTY OF 5 1/2 INCHES OF RAIN THIS
MORNING.

PFEIFFER
Special weather statement, Jun 20, 12:41 PM CDT, 2 hours before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
1240 PM CDT FRI JUN 20 1986

AT 1230 PM CDT...INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN HAD
DEVELOPED OVER SOUTHEAST SOUTH DAKOTA. THESE STORMS EXTENDED FROM
25 MILES SOUTHWEST OF SIOUX FALLS TO YANKTON.

THESE STORMS ARE CAPABLE OF PRODUCING GUSTY WINDS AND HAIL ALONG
WITH LOCALLY HEAVY DOWNPOURS. PERSONS IN SOUTHEAST SOUTH DAKOTA
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS.

ELSEWHERE...SCATTERED SHOWERS WERE OCCURRING OVER EASTERN SOUTH
DAKOTA AND SOUTHERN NORTH DAKOTA.

ALL MOVEMENT WAS NORTH AT 20 MILES AN HOUR.

MORRIS
Special weather statement, Jun 20, 12:47 PM CDT, 1 hour 54 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1245 PM CDT FRI JUN 20 1986

AT 1235 PM CDT RADAR SHOWED A CLUSTER OF INTENSE THUNDERSTORMS
DEVELOPING FROM 15 MILES WEST NORTHWEST SIOUX FALLS TO YANKTON.
THE THUNDERSTORMS WERE MOVING NORTHNORTHEAST AT 35 MPH.

THE THUNDERSTORMS WILL PRODUCE VERY HEAVY RAIN...DANGEROUS CLOUD TO
GROUND LIGHTNING AND POSSIBLY HAIL AND STRONG GUSTY WINDS.

RESIDENTS NEAR OR NORTHNORTHEAST OF THIS AREA SHOULD BE PREPARED
FOR THE ADVERSE WEATHER THESE THUNDERSTORMS MAY BRING AND MOVE TO
A SAFE PLACE IF NECESSARY.
BLOOM
Special weather statement, Jun 20, 1:31 PM CDT, 1 hour 10 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
125 PM CDT FRI JUN 20 1986

....THUNDERSTORMS DEVELOP RAPIDLY ACROSS SIOUXLAND....

NUMEROUS CLUSTERS OF THUNDERSTORMS HAVE DEVELOPED ACROSS THE MUCH
OF SIOUXLAND. THE MOST INTENSE THUNDERSTORM WAS LOCATED 45 MILES
NORTHWEST OF SIOUX CITY. THE THUNDERSTORMS WERE MOVG TO THE NORTHEAST
AT 35 MPH.

THESE THUNDERSTORMS WILL PRODUCE HEAVY RAIN POSSIBLY HAIL AND STRONG
GUSTY WIND.
E
PERSONS NEAR THE AREA OF THSES THUNDERSTORMS SHOULD BE PREPARED TO
MOVE TO A SAFE PLACE IF THREATENING WEATHER APPROACHES.

FREDERICK
Special weather statement, Jun 20, 1:35 PM CDT, 1 hour 6 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE HURON SD
135 PM CDT FRI JUN 20 1986

AT 130 PM CDT...INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN
CONTINUED OVER SOUTHEAST SOUTH DAKOTA AND EXTENDED INTO
SOUTHWEST MINNESOTA. THE THUNDERSTORMS WERE IN A 100 MILE
WIDE AREA FROM YANKTON SOUTH DAKOTA TO 40 MILES NORTHWEST
OF REDWOOD FALLS MINNESOTA.

THE STRONGEST STORMS EXTENDED FROM 15 MILES SOUTHWEST OF
SIOUX FALLS TO BROOKINGS. INTENSITY OF THE STORMS HAD INCREASED
SINCE 1230 PM CDT.

THESE STORMS ARE CAPABLE OF PRODUCING GUSTY WINDS AND HAIL ALONG
WITH LOCALLY HEAVY DOWNPOURS. PERSONS IN SOUTHEAST SOUTH DAKOTA
SHOULD REMAIN ALERT FOR RAPIDLY CHANGING WEAT*HER CONDITIONS.

ALL MOVEMENT WAS NORTH-NORTHEAST AT 20 MILES AN HOUR.
MORRIS

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; the sounding from the Mesonet's radiosonde archive.