Alert archive / Iowa / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 49, NWS Des Moines, IA

June 11, 1987Franklin County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 11, 1987, 6:02 PM CDT for Franklin County, Iowa. It was in force for 15 min.

The area

The counties it named.

The facts

Issued
Jun 11, 1987, 6:02 PM CDT (23:02 UTC)
Expired
Jun 11, 1987, 6:17 PM CDT
In force
15 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Franklin 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

Minneapolis, MN (KSTC), launched 12:00Z, 11.0 hours before the alert went out and 237 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, Minneapolis, MN at 12:00Z on 1987-06-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 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, Minneapolis, MN at 12:00Z on 1987-06-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 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
22 J/kg
Mixed-layer CIN
-202 J/kg
Mixed-layer LCL
1137 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
140 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 KALO 112302
SVRALO
IAC069-120000-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE WATERLOO IA
602 PM CDT THU JUN 11 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL  700 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN NORTH CENTRAL IOWA
          ...SOUTHERN FRANKLIN
 
AT 600PM CDT NATIONAL WEATHER SERVICE RADAR AT WATERLOO SHOWED A
SEVERE THUNDERSTORM NEAR POPEJOY 35 MILES EAST OF FORT DODGE.
THIS STORM WAS MOVING EAST AT 30 MPH.
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.

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, Jun 11, 4:43 PM CDT, 1 hour 19 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
440 PM CDT THU JUN 11 1987

...A LINE OF VERY STRONG THUNDERSTORMS CONTINUE IN NORTHEAST IOWA...

AT 435 PM CDT WATERLOO RADAR SHOWED A LINE OF VERY STRONG THUNDERSTORMS
STRETCHING FROM NEAR OSAGE...ABOUT 15 MILES NORTHEAST OF MASON CITY TO
ABOUT 15 MILES NORTHEAST OF FORT DODGE.

THE STRONGEST STORMS WERE LOCATED NEAR OSAGE AND NEAR CLARION...20
MILES NORTHEAST OF FORT DODGE.&

THESE THUNDERSTORMS WERE MOVING EAST AT 15 MILES AN HOUR.

IF YOU ARE IN THE PATH OF THESE STORMS YOU CAN EXPECTED BRIEF HEAVY
RAIN AND SMALL HAIL AS THEY PASS BY.
HAYS
Special weather statement, Jun 11, 4:46 PM CDT, 1 hour 16 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
446 PM CDT THU APR 11 1987

AT 435 PM...A BAND OF INTENSE THUNDERSTORMS HAD DEVELOPED OVER
NORTH CENTRAL IOWA. THE STORMS WERE LOCATED IN A 20 MILE WIDE
AREA THAT STRETCHED FROM 70 MILES NORTH OF DES MOINES NEAR
CLARION NORTHEAST TO OSAGE...25 MILES NORTHEAST OF MASON CITY.
DUE TO THE RAPID DEVELOPMENT OF THESE STORMS...VERY HEAVY RAIN
...GUSTY WINDS AND SMALL HAIL IS LIKELY. THE STRONGEST STORMS
IN THIS BAND WERE LOCATED JUST NORTHWEST AND NORTHEAST OF CLARION.

ELSEWHERE A SMALL CLUSTER OF STORMS WAS LOCATED 30 MILES NORTHWEST
OF MASON CITY ALONG THE IOWA/MINNESOTA BORDER...WHILE ISOLATED LIGHT+
SHOWERS AND THUNDERSHOWERS WERE LOCATED OVER THE SOUTHEAST THIRD OF
IOWAS COUNTIES.

THE OVERALL MOVEMENT OF THE SHOWERS AND STORMS WAS EAST AT 25 MILES
AN HOUR.
BARLOW
Special weather statement, Jun 11, 5:47 PM CDT, 15 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
545 PM CDT THU APR 11 1987

AT 535 PM...A 20 MILE WIDE BAND OF INTENSE THUNDERSTORMS WAS
LOCATED FROM NORTH CENTRAL INTO NORTHEAST IOWA. THE BAND STRETCHED
FROM 30 MILES SOUTH OF MASON CITY...NEAR CLARION NORTHEAST TO
20 MILES NORTHWEST OF DECORAH. PEA TO MARBLE SIZED HAIL...VERY
HEAVY RAIN AND GUSTY WINDS CAN BE EXPECTED WITH THESE STORMS.

A SMALL CLUSTER OF SHOWERS AND THUNDERSHOWERS WAS LOCATED 10 MILES
NORTHWEST OF MASON CITY...WHILE ISOLATED SHOWERS WERE LOCATED OVER
THE EXTREME EAST CENTRAL AND SOUTHEAST COUNTIES OF THE STATE.

THE SHOWERS AND STORMS WERE MOVING EAST AT 20 MILES AN HOUR.
s
BARLOW

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 11, 4:57 PM CDTSevere Thunderstorm WarningDMXWright33 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.