Alert archive / Iowa / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 4, NWS Des Moines, IA

May 2, 1987Polk County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 2, 1987, 4:10 PM CDT for Polk County, Iowa. It was in force for 50 min.

The area

The counties it named.

The facts

Issued
May 2, 1987, 4:10 PM CDT (21:10 UTC)
Expired
May 2, 1987, 5:00 PM CDT
In force
50 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Polk 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, 9.2 hours before the alert went out and 236 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 1987-05-02Temperature 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 1987-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 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
3602 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
40 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 022110
SVRDSM
IAC153-022200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
410 PM CDT SAT MAY 2 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 500 PM CDT FOR PEOPLE IN THE FOLLOWING 
COUNTY OF

CENTRAL IOWA...
 POLK

AT 405 PM RADAR INDICATED A SEVERE STROM IN NORTHWEST POLK COUNTY
..OR AROUND 10 MILES TO THE NORTHWEST OF DES MOINES.

THE STORM WAS MOVING SOUTHEAST AT 15 MILES AN HOUR AND WILL BE
INTO THE GREATER DES MOINES AREA BETWEEN 415 PM AND 445 PM.

AT 4 PM DIME SIZE TO 1/2 INCH SIZE HAIL OCCURED AT FISHER LAKE ON
GRIMES ROAD OR JUST NORTH OF DES MOINES.

REMEMBER..A SEVERE THUNDERSTORM CAN PRODUCE DAMAGING WINDS IN EXCESS
OF 60 MPH..LARGE HAIL..DEADLY LIGHTNING..AND HEAVY RAINS THAT CAN
QUICKLY FLOOD LOW LYING AREAS.  PEOPLE IN THE PATH OF THIS STORM
SHOULD TAKE APPROPRIATE ACTION IMMEDIATELY.

WEINBRECHT/KS

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, May 2, 2:46 PM CDT, 1 hour 24 minutes before
<PQ<
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
245 PM CDT SATURDAY MAY 2 1987

...THUNDERSTORMS MOVING INTO DES MOINES AND AMES...

THUNDERSTORMS HAVE BEEN DEVELOPING TO THE WEST OF DES MOINES
AND AMES AND ARE NOW MOVING INTO THESE MUNICIPALITIES.  MOST
REPORTS RECEIVED HAVE ONLY INCLUDED HEAVY RAINS WITH THESE STORMS
...BUT PEA SIZE HAIL WAS OBSERVED AT WAUKEE AT APPROXIMATELY 230 PM.

THESE THUNDERSTORMS ARE ALSO CAPABLE OF PRODUCING WIND GUSTS IN THE
RANGE OF 30 TO 35 MILES AN HOUR.  THUS IT IS RECOMMENDED THAT BOATERS
AND SWIMMERS ON AREA LAKES...INCLUDING SAYLORVILLE LAKE...HEAD IN FOR
SHORE BEFORE THESE STORMS ARRIVE.  LIGHTNING SAFETY PRECAUTIONS NEED
ALSOY BE OBSERVED.

DOWD

The office that day

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

IssuedProductOfficeCountiesLasted
May 2, 3:32 PM CDTTornado WarningDMXPolk38 min
May 2, 5:23 PM CDTSevere Thunderstorm WarningDMXJasper27 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.