Alert archive / Iowa / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 29, NWS Sioux Falls, SD

July 5, 1987Monona County, Woodbury County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 5, 1987, 5:05 PM CDT for Monona County, Woodbury County, Iowa. It was in force for 55 min.

The area

The counties it named.

The facts

Issued
Jul 5, 1987, 5:05 PM CDT (22:05 UTC)
Expired
Jul 5, 1987, 6:00 PM CDT
In force
55 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Monona County, IA, Woodbury 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, 10.1 hours before the alert went out and 105 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 1987-07-05Temperature 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 1987-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 22 square meters per square second.1939Sfc1 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
3609 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
22 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 KSUX 052205
SVRSUX
IAC133-193-052300-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX CITY IA
505 PM CDT SUN JUL 5 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL  600 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN WEST CENTRAL IOWA
          ...MONONA...WOODBURY
 
AT 500 PM CDT A SEVERE THUNDERSTORM WAS INDICATED BY RADAR NEAR SLOAN
OR ABOUT 25 MILES SOUTHWEST OF SIOUX CITY.
 
THE STORM WAS MOVING EAST AT 35 MILES AN HOUR.
 
THESE STORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE OR
NO WARNING.
 
 
 
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN ITS PATH YOU SHOULD
PREPARE FOR D'AMAGING WIND IN EXCESS OF 55 MPH...LARGE HAIL...AND
DEADLY LIGHTNING.  PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT STAY AWAY FROM WINDOWS.
KROPP

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, Jul 5, 1:31 PM CDT, 3 hours 34 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
130 PM CDT SUN JUL 5 1987

...STRONG THUNDERSTORMS AND HEAVY RAIN IN CHEROKEE AND OBRIEN COUNTIES
IN IOWA...

AT 125 PM CDT RADAR SHOWED TWO STRONG THUNDERSTORMS IN NORTHWEST IOWA.
THE FIRST WAS 50 MILES NORTHEAST OF SIOUX CITY IN WESTERN OBRIEN COUNTY
15 MILES WEST OF PRIMGHAR IOWA. THE SECOND WAS 40 MILES NORTHEAST OF
SIOUX CITY OR 5 MILES WEST OF CHEROKEE IOWA. THESE STORMS WERE MOVING TO
THE NORTH NORTHEAST AT 20 MILES AN HOUR.

THESE STORMS ARE CAPABLE OF PRODUCING HEAVY RAIN...SMALL HAIL AND
STRONG GUSTY WINDS. PEOPLE IN NORTHERN CHEROKEE AND OBRIEN COUNTIES
SHOULD BE ALERT AS THESE THUNDERSTORMS MOVE THROUG`H THE AREA.

ROSNER
Special weather statement, Jul 5, 2:11 PM CDT, 2 hours 54 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
210 PM CDT SUN JUL 5 1987

AT 2 PM CDT...THUNDERSTORMS CONTINUED TO DEVELOP OVER NORTHWEST IOWA
AND WERE NOW DEVELOPING IN EXTREME SOUTHWEST MINNESOTA. THEY WERE IN
AN AREA 30 MILES WIDE FROM 20 MILES SOUTHEAST OF SIOUX CITY IOWA TO
15 MILES NORTHEAST OF WORTHINGTON MINNESOTA.

THE HEAVIEST STORMS WERE 25 MILES EAST OF SIOUX CITY IOWA NEAR
CORRECTIONVILLE IOWA...NORTH OF CHERuOKEE IOWA...NEAR SANBORN IOWA AND
10 MILES EAST OF WORTHINGTON MINNESOTA. THESE STORMS MAY PRODUCE HEAVY
RAIN...STRONG WINDS...SMALL HAIL AND DANGEROUS LIGHTNING.

MOVEMENT WAS NORTHEAST AT 25 MPH.
 BLAIR
Special weather statement, Jul 5, 2:13 PM CDT, 2 hours 52 minutes before
^DSMSPSSUX
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX CITY IA
210 PM CDT SUN JUL 5 1987

...STRONG THUNDERSTORMS IN NORTHWEST IOWA...

AT 205 PM CDT RADAR SHOWED A 30 MILE WIDE BAND OF THUNDERSTORMS OVER
NORTHWEST IOWA. THIS BAND EXTENDED FROM 90 MILES NORTHEAST OF SIOUX CITY
TO 40 MILES EAST OF SIOUX CITY. THE STRONGEST THUNDERSTORM WAS LOCATED
45 MILES NORTHEAST OF SIOUX CITY OR NEAR CHEROKEE IOWA. THIS
THUNDERSTORM HAD PRODUCED PEA TO MARBLE SIZE HAIL AS IT MOVED THROUGH
CHEROKEE. THESE STORMS WERE MOVING TO THE NORTHEAST AT 25 MILES AN HOUR.

THESE STORMS ARE CAPABLE OF PRODUCING HEAVY RAIN...SMALL HAIL AND
STRONG GUSTY WINDS. PEOPLE IN NORTHERN CHEROKEE AND OBRIEN COUNTIES
SHOULD BE ALERT AS THESE THUNDERSTORMS MOVE THROUGH THE AREA AND BE
PREPARED TO TAKE COVER IF NEEDED.

ROSNER
Special weather statement, Jul 5, 3:11 PM CDT, 1 hour 54 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
310 PM CDT SUN JUL 5 1987

AT 3 PM CDT...STRONG THUNDERSTORMS CONTINUED OVER NORTHWEST IOWA AND
EXTREME SOUTHWEST MINNESOTA. THEY WERE IN AN AREA 40 MILES WIDE FROM
30 MILES EAST OF SIOUX CITY IOWA TO MOUNTAIN LAKE MINNESOTA...WHICH IS
ABOUT 50 MILES SOUTHWEST OF MANKATO. THESE STORMS HAVE BEEN DROPPING
HEAVY RAIN AND PEA TO MARBLE SIZE HAIL AND MAY ALSO PRODUCE GUSTY
WINDS AND DANGEROUS LIGHTNING.

THE STRONGEST STORMS IN IOWA WERE NORTHEAST OF LE MARS...NEAR SIBLEY...
NEAR SANBORN AND OVER LAKE PARK. IN MINNESOTA THE STONGEST STORMS WERE
NEAR LAKEFIELD AND OVER WINDOM.

MOVEMENT WAS NORTHEAST AT 20 MPH.
 BLAIR

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 6:11 PM CDTSevere Thunderstorm WarningFSDMonona, Woodbury64 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; the sounding from the Mesonet's radiosonde archive.