Alert archive / Iowa / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 40, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 7, 1987, 1:00 AM CDT for Lyon County, Osceola County, Sioux County, Iowa. It was in force for 60 min. 2 reports 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
- Jul 7, 1987, 1:00 AM CDT (06:00 UTC)
- Expired
- Jul 7, 1987, 2:00 AM CDT
- In force
- 60 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 7, 1:23 AM CDT | Tornado F2 | Sioux, IA | |
| Jul 7, 1:30 AM CDT | Thunderstorm Wind 58 | Sioux, 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 00:00Z, 6.0 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.
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KFSD 070600
SVRFSD
IAC119-143-167-070700-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
100 AM CDT TUE JUL 7 1987
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL 200 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES...
IN NORTHWEST IOWA
...LYON...WESTERN OSCEOLA...SIOUX
SOME CITIES INCLUDED IN THIS WARNING...SIOUX CENTER...LESTER...
GEORGE...SIBLEY.
AT 1 AM CDT RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS FROM 20
MILES SOUTHEAST OF SIOUX FALLS TO 35 MILES SOUTH SOUTHEAST OF SIOUX
FALLS. THE LINE WAS MOVING EAST AT 25 MPH.
LARGE HAIL AND VERY HEAVY RAINS CAN BE EXPECTED WITH THIS LINE.
IF YOU ARE IN THE PATH OF THIS STORM...YOU SHOULD GET TO A
REINFORCED SHELTER. A SEVERE THUNDERSTORM PRODUCES WINDS IN EXCESS
OF 60 MPH...HAIL 3/4 INCH OR LARGER...DEADLY LIGHTNING...AND HEAVY
RAIN THAT CAN QUICKLY FLOOD A LOW LYING AREA.
THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE
OR NO ADVANCE WARNING SO BE ON THE LOOKOUT.
JANSENWhat 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 6, 10:31 PM CDT, 2 hours 29 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 1030 PM CDT MON JUL 6 1987 AT 1030 PM CDT INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN CONTINUED ACROSS A LARGE PORTION OF SOUTHEAST SOUTH DAKOTA. THE STORMS EXTENDED FROM 40 MILES SOUTHWEST OF SIOUX FALLS...NEAR FREEMAN TO 35 MILES NORTH OF SIOUX FALLS...NEAR MADISON. THE STRONGEST THUNDERSTORMS WERE LOCATED BETWEEN BRIDGEWATER AND HOWARD. THESE THUNDERSTORMS ARE CAPABLE OF PRODUCING VERY HEAVY RAIN THAT COULD FLOOD LOW LYING AREAS...HAIL...DANGEROUS LIGHTNING...AND STRONG WINDS OF 40 TO 50 MILES AN HOUR AS THEY MOVE EAST AT 20 MILES AN HOUR. PERSONS IN THE SOUTH DAKOTA COUNTIES OF HUTCHINSON...MCCOOK...LAKE ...MINNEHAHA INCLUDING THE COMMUNITIES OF FREEMAN...BRIDGEWATER... SALEM AND SIOUX FALLS SHOULD BE ON THE LOOKOUT FOR THESE STORMS UNTIL MIDNIGHT. STAY TUNED TO YOUR LOCAL RAIO AND TV STATION FOR FURTHER STATEMENTS OR POSSIBLE WARNINGS. BUSS
Special weather statement, Jul 6, 11:42 PM CDT, 1 hour 18 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX FALLS SD 1140 PM CDT MON JUL 6 1987 ...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 4 AM CDT FOR EXTREME SOUTHEAST SOUTH DAKOTA...SOUTHWEST MINNESOTA AND NORTHWEST IOWA... AT 1135 PM CDT RADAR INDICATED A LINE OF INTENSE THUNDERSTORMS FROM NEAR PIPESTONE MINNESOTA SOUTHWEST THROUGH SIOUX FALLS TO YANKTON SOUTH DAKOTA AND INTO NORTHEAST NEBRASKA. THE HEAVIEST THUNDERSTORMS WERE LOCATED 15 MILES NORTHEAST OF SIOUX FALLS NEAR GARRETSON...10 MILES SOUTHWEST OF SIOUX FALLS NEAR LENNOX...15 MILES NORTHEAST OF YANKTON AND JUST SOUTH OF FREEMAN SOUTH DAKOTA. THSE THUNDERSTORMS ARE CAPABLE OF PRODUCING STRONG GUSTY WINDS... SMALL HAIL...HEAVY RAINS AND DANGEROUS CLOUD TO GROUNG LIGHTNING. THIS LINE OF STORMS WAS MOVING EAST AT 20 MPH AND WILL BE AFFECTING CLAY AND LINCOLN COUNTIES OF SOUTH DAKOTA...ROCK COUNTY OF SOUTHWEST MINNESOTA AND LYON COUNTY OF NORTHWEST IOWA BY 1P230 AM CDT. PERSON ACROSS SOUTHEAST SOUTH DAKOTA...NORTHWEST IOWA AND SOUTHWEST MINNESOTA SHOULD KEEP ABREAST OF THIS WEATHER SITUATION AND BE PREPARED TO SEEK SHELTER IF A WARNING IS ISSUED. JANSEN
Local storm report, Jul 7, 12:22 AM CDT, 38 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT TUE JUL 7 1987
949 PM CDT PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
(DAVISON COUNTY)
1007 PM CDT GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
(MINNEHAHA COUNTY)
1155 PM CDT 52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
(CLAY COUNTY)
1217 AM CDT PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
SOUTH DAKOTA. (pLINCOLN COUNTY)
JANSENLocal storm report, Jul 7, 12:23 AM CDT, 37 minutes before
STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 AM CDT TUE JUL 7 1987
949 PM CDT PEA SIZE HAIL AND HEAVY RAIN NEAR MITCHELL SOUTH DAKOTA.
(DAVISON COUNTY)
1007 PM CDT GUST TO 41 MPH AT THE SIOUX FALLS AIRPORT.
(MINNEHAHA COUNTY)
1155 PM CDT 52 MPH WINDS AT VERMILLION SOUTH DAKOTA.
(CLAY COUNTY)
1217 AM CDT PEA TO MARBLE SIZE HAIL COVERING GROUND AT BERESFORD
SOUTH DAKOTA. (qLINCOLN COUNTY)
JANSENSpecial weather statement, Jul 7, 12:45 AM CDT, 15 minutes before
^DSMSPSSUX SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX CITY IA 1243 AM CDT TUE JUL 7 1987 ...VERU STRONG THUNDERSTORMS MOVING ACROSS UNION COUNTY SOUTH DAKOTA... AT 1240 AM CDT RADAR INDICATED VERY STRONG THUNDERSTORMS MOVING ACROSS UNION COUNTY SOUTH DAKOTA...ABOUT 20 TO 45 MILES NORTHWEST OF SIOUX CITY. THESE THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR. THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL...HEAVLY RAIN SHOWER AND STRONG GUSTY WINDS. RESIDENTS OF UNION COUNTY SOUTH DAKOTA SHOULD BE ON THE LOOKOUT FOR ANY SEVERE WEATHER AND TAKE SHELTER IMMEDIATELY IF IT IS OBSERVED. SHERLIN
Special weather statement, Jul 7, 12:56 AM CDT, 4 minutes before
^DSMSPSSUX SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SIOUX CITY IA 1255 AM CDT TUE JUL 7 1987 ...VERY STRONG THUNDERSTORMS MOVING INTO WESTERN IOWA... AT 1250 AM CDT RADAR INDICATED A LINE OF VERY STRONG THUNDERSTORMS WAS MOVING INTO WESTERN IOWA. THESE STORMS EXTENDED ALL THE WAY FROM THE EXTREME NORTHWEST CORNER OF IOWA SOUTHWARD INTO MONONA COUNTY...ABOUT 45 MILES SOUTHEAST OF SIOUX CITY. THESE THUNDERSTORMS WILL PRODUCE PEA TO MARBLE SIZE HAIL. WIND GUSTS TO AROUND 50 MILES AN HOUR...DANGEROUS LIGHTNING AND HEAVY SHOWERS. RESIDENTS OF SIOUX...PLYMOUTH...WOODBURY AND MONONA COUNTIES IN WESTERN IOWA SHOULD BE ON THE LOOKOUT FOR THESE VERY STRONG STORMS AND TAKE SHTELTER IF SEVERE WEATHER IS OBSERVED. SHERLIN
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 7, 12:33 AM CDT | Severe Thunderstorm Warning | FSD | Lyon, Sioux | 57 min |
| Jul 7, 1:07 AM CDT | Severe Thunderstorm Warning | FSD | Monona, Woodbury | 53 min |
| Jul 7, 1:07 AM CDT | Severe Thunderstorm Warning | FSD | Plymouth | 53 min |
| Jul 7, 1:27 AM CDT | Severe Thunderstorm Warning | FSD | Cherokee, O'Brien | 63 min |
| Jul 7, 1:46 AM CDT | Severe Thunderstorm Warning | FSD | Ida | 59 min |
| Jul 7, 2:08 AM CDT | Severe Thunderstorm Warning | FSD | Monona | 37 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.