Alert archive / Iowa / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 29, NWS Des Moines, IA

April 25, 1998Dallas County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 25, 1998, 6:02 PM CDT for Dallas County, Iowa. It was in force for 33 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
Apr 25, 1998, 6:02 PM CDT (23:02 UTC)
Expired
Apr 25, 1998, 6:35 PM CDT
In force
33 min
Issued by
NWS Des Moines, IA
Area
Whole counties

County Dallas County, IA

What was reported inside it

TimeReportWhereRemark
Apr 25, 6:11 PM CDTHail 1Adel, IA
Apr 25, 6:23 PM CDTHail 1Granger, 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Apr 25, 5:30 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.0 hours before the alert went out and 198 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 1998-04-25Temperature 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 1998-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -48 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1241 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

112 
WUUS1 KDSM 252303 RRA
SVRDSM
IAC049-252335-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
602 PM CDT SAT APR 25 1998

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN DALLAS COUNTY IN CENTRAL IOWA

* UNTIL 635 PM CDT

* AT 602 PM CDT... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 28
  MILES SOUTH OF DES MOINES OR 24 MILES SOUTH SOUTHEAST OF
  BOONEVILLE MOVING NORTH NORTHEAST AT 45 MPH.

* THIS STORM IS EXPECTED TO REMAIN IN RURAL AREAS.

GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS A TORNADO
WATCH IS IN EFFECT. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO
PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE WARNING.

SMITH

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, Apr 25, 1:45 PM CDT, 4 hours 17 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-261100-

CENTRAL IOWA THUNDERSTORM OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE DES MOINES IA
145 PM CDT SAT APR 25 1998

HAZARD--THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.  SOME STORMS
COULD HAVE HEAVY RAIN.

AREA OF CONCERN--THUNDERSTORMS ARE POSSIBLE ACROSS ALL OF CENTRAL IOWA
BUT THE LIKELIHOOD OF SEVERE WEATHER WILL PRIMARILY BE SOUTH OF HIGHWAY
92 AND WEST OF HIGHWAY 169.

TIMING--THUNDERSTORMS WILL REDEVELOP AFTER 4 PM BUT THE BEST TIME FOR
SEVERE WEATHER WILL BE BETWEEN 5 TO 10 PM.

METEOROLOGICAL COMMENTS--LOW PRESSURE OVER THE EASTERN KANSAS/NEBRASKA
BORDER IS CONTINUING TO CREEP EAST.  SUFFICIENT HEATING IS OCCURRING
OVER SOUTHWEST IOWA AS MOISTURE CONTINUES TO STREAM NORTHWARD.  THE
MOISTURE IS IN A FAIRLY NARROW BAND ALONG AND NORTH OF A SURFACE WARM
FRONT STRETCHED ACROSS NORTHERN MISSOURI.  AS COLDER AIR WRAPS AROUND
AROUND THE LOW AT 700 MB THE THREAT FOR SEVERE THUNDERSTORMS WILL
INCREASE.  AT THIS TIME IT APPEARS THE BEST TIME FOR SEVERE WEATHER WILL
BE DURING THE EARLY EVENING HOURS.

PRECAUTIONS--EMERGENCY MANAGERS MAY WANT TO ALERT THEIR COUNTY SPOTTERS
TO THE LIKELIHOOD OF THUNDERSTORMS FOR THE AFTERNOON AND THE POSSIBILITY
SEVERE STORMS AFTER 5 PM.  THE BEST CHANCE FOR SEVERE WEATHER WILL BE
ALONG AND SOUTH OF HIGHWAY 92 AND WEST OF HIGHWAY 169.  KEEP AN EYE TO
THE SKY FOR THE DEVELOPMENT OF THUNDERSTORMS THIS AFTERNOON AND BE
PREPARED TO ACT QUICKLY.

FAB
Special weather statement, Apr 25, 4:00 PM CDT, 2 hours 2 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-261100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
400 PM CDT SAT APR 25 1998

HAZARD--THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.

AREA OF CONCERN--THUNDERSTORMS ARE POSSIBLE ACROSS ALL OF CENTRAL IOWA
BUT THE LIKELIHOOD OF SEVERE WEATHER WILL PRIMARILY BE SOUTH OF HIGHWAY
92 AND WEST OF HIGHWAY 169.

TIMING--THUNDERSTORMS WILL REDEVELOP AFTER 5 PM BUT THE BEST TIME FOR
SEVERE WEATHER WILL BE BETWEEN 6 TO 9 PM.

METEOROLOGICAL COMMENTS--LOW PRESSURE OVER THE EASTERN KANSAS/NEBRASKA
BORDER IS CONTINUING TO CREEP EAST.  A CAP AT 700 MB IS PREVENTING
CONVECTION FROM STARTING HOWEVER THIS CAP IS EXPECTED TO ERODE AWAY AS
COLDER AIR ALOFT WRAPS INTO THE LOW IN EASTERN NEBRASKA.  THE CAP IS
EXPECTED TO BREAK EARLY THIS EVENING AND IF IT DOES...THUNDERSTORMS WILL
ERUPT.  THESE STORMS HAVE THE POTENTIAL FOR LARGE HAIL AND DAMAGING
WIND.  AT THIS TIME ONLY A COUPLE THUNDERSTORMS ARE BEING PICKED UP BY
RADAR BUT THEY ARE WEAK.  WIDESPREAD THUNDERSTORM DEVELOPMENT IS NOT
EXPECTED UNTIL AFTER 5 PM WITH THE POTENTIAL FOR SEVERE STORMS AFTER 6
PM.

PRECAUTIONS--EMERGENCY MANAGERS MAY WANT TO ALERT THEIR COUNTY SPOTTERS
TO THE LIKELIHOOD OF THUNDERSTORMS FOR THE AFTERNOON AND THE POSSIBILITY
SEVERE STORMS AFTER 5 PM.  THE BEST CHANCE FOR SEVERE WEATHER WILL BE
ALONG AND SOUTH OF HIGHWAY 92 AND WEST OF HIGHWAY 169.  KEEP AN EYE TO
THE SKY FOR THE DEVELOPMENT OF THUNDERSTORMS THIS AFTERNOON AND BE
PREPARED TO ACT QUICKLY.

FAB
Special weather statement, Apr 25, 4:00 PM CDT, 2 hours 2 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-261100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
400 PM CDT SAT APR 25 1998

HAZARD--THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS.

AREA OF CONCERN--THUNDERSTORMS ARE POSSIBLE ACROSS ALL OF CENTRAL IOWA
BUT THE LIKELIHOOD OF SEVERE WEATHER WILL PRIMARILY BE SOUTH OF HIGHWAY
92 AND WEST OF HIGHWAY 169.

TIMING--THUNDERSTORMS WILL REDEVELOP AFTER 5 PM BUT THE BEST TIME FOR
SEVERE WEATHER WILL BE BETWEEN 6 TO 9 PM.

METEOROLOGICAL COMMENTS--LOW PRESSURE OVER THE EASTERN KANSAS/NEBRASKA
BORDER IS CONTINUING TO CREEP EAST.  A CAP AT 700 MB IS PREVENTING
CONVECTION FROM STARTING HOWEVER THIS CAP IS EXPECTED TO ERODE AWAY AS
COLDER AIR ALOFT WRAPS INTO THE LOW IN EASTERN NEBRASKA.  THE CAP IS
EXPECTED TO BREAK EARLY THIS EVENING AND IF IT DOES...THUNDERSTORMS WILL
ERUPT.  THESE STORMS HAVE THE POTENTIAL FOR LARGE HAIL AND DAMAGING
WIND.  AT THIS TIME ONLY A COUPLE THUNDERSTORMS ARE BEING PICKED UP BY
RADAR BUT THEY ARE WEAK.  WIDESPREAD THUNDERSTORM DEVELOPMENT IS NOT
EXPECTED UNTIL AFTER 5 PM WITH THE POTENTIAL FOR SEVERE STORMS AFTER 6
PM.

PRECAUTIONS--EMERGENCY MANAGERS MAY WANT TO ALERT THEIR COUNTY SPOTTERS
TO THE LIKELIHOOD OF THUNDERSTORMS FOR THE AFTERNOON AND THE POSSIBILITY
SEVERE STORMS AFTER 5 PM.  THE BEST CHANCE FOR SEVERE WEATHER WILL BE
ALONG AND SOUTH OF HIGHWAY 92 AND WEST OF HIGHWAY 169.  KEEP AN EYE TO
THE SKY FOR THE DEVELOPMENT OF THUNDERSTORMS THIS AFTERNOON AND BE
PREPARED TO ACT QUICKLY.

FAB

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 25, 5:45 PM CDTSevere Thunderstorm WarningDMXClarke35 min
Apr 25, 5:56 PM CDTSevere Thunderstorm WarningDMXMadison34 min
Apr 25, 6:20 PM CDTSevere Thunderstorm WarningDMXWarren35 min
Apr 25, 6:21 PM CDTSevere Thunderstorm WarningDMXDallas34 min
Apr 25, 6:51 PM CDTSevere Thunderstorm WarningDMXCarroll34 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1998Every severe thunderstorm warning in 1998

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.