Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 281, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 4, 1998, 1:41 PM CDT for Mahaska County, Wapello County, Iowa. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 4, 1998, 1:41 PM CDT (18:41 UTC)
- Expired
- Aug 4, 1998, 2:15 PM CDT
- In force
- 34 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Mahaska County, IA, Wapello County, IA
The radar
The Des Moines radar (KDMX), 117 km from the middle of the area, began a volume at 18:41 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 6.7 hours before the alert went out and 176 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
- 1229 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 914 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 78 m²/s²
- 0-3 km storm-relative helicity
- 132 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 KDSM 041841 SVRDSM IAC123-179-041915- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE DES MOINES IA 141 PM CDT TUE AUG 4 1998 THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTH CENTRAL AND SOUTHEASTERN MAHASKA COUNTY IN SOUTH CENTRAL IOWA NORTHERN WAPELLO COUNTY IN SOUTHEASTERN IOWA * UNTIL 215 PM CDT * AT 139 PM CDT... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 11 MILES NORTH NORTHWEST OF OTTUMWA OR 4 MILES SOUTHWEST OF FREMONT MOVING EAST AT 15 MPH. * THIS STORM CAN BE EXPECTED NEAR... EDDYVILLE NOW KIRKVILLE BY 145 PM CDT FREMONT BY 148 PM CDT DAMAGINNG WINDS AND LARGE HAIL ARE LIKELY. GO INSIDE A STURDY BUILDING AND STAY AWAY FROM WINDOWS! SS/AK
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, Aug 4, 11:43 AM CDT, 1 hour 58 minutes before
IAZ057-041745- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1143 AM CDT TUE AUG 4 1998 SLOW MOVING THUNDERSTORMS NEAR AUDUBON HAVE PRODUCED A WEAK FUNNEL CLOUD. THE STORM IS RELATIVELY WEAK AND IS NOT THE TYPE OF STORM THAT WOULD PRODUCE SEVERE WEATHER. THE FUNNEL MAY APPROACH THE GROUND AND MAY EVEN BRIEFLY TOUCH DOWN WITH WEAK WINDS...LESS THAN 60 MPH. MORE STORMS ARE DEVELOPING QUICKLY IN THE WARM AND UNSTABLE ENVIRONMENT ACROSS THE STATE. THE MAIN THREAT FROM THESE STORMS WILL BE INTENSE RAINFALL...LIKELY EXCEEDING AN INCH AN HOUR. MYERS
Special weather statement, Aug 4, 11:43 AM CDT, 1 hour 58 minutes before
IAZ057-041745- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 1143 AM CDT TUE AUG 4 1998 SLOW MOVING THUNDERSTORMS NEAR AUDUBON HAVE PRODUCED A WEAK FUNNEL CLOUD. THE STORM IS RELATIVELY WEAK AND IS NOT THE TYPE OF STORM THAT WOULD PRODUCE SEVERE WEATHER. THE FUNNEL MAY APPROACH THE GROUND AND MAY EVEN BRIEFLY TOUCH DOWN WITH WEAK WINDS...LESS THAN 60 MPH. MORE STORMS ARE DEVELOPING QUICKLY IN THE WARM AND UNSTABLE ENVIRONMENT ACROSS THE STATE. THE MAIN THREAT FROM THESE STORMS WILL BE INTENSE RAINFALL...LIKELY EXCEEDING AN INCH AN HOUR. MYERS
Special weather statement, Aug 4, 11:54 AM CDT, 1 hour 47 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-041750-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
1154 AM CDT TUE AUG 4 1998
...THUNDERSTORMS BEGINNING TO EXPAND...
THUNDERSTORMS PRODUCING INTENSE RAINFALL ARE BEGINNING TO INCREASE
IN COVERAGE ACROSS IOWA. STORMS ARE INCREASING IN WEST CENTRAL AND
CENTRAL IOWA AS SUNSHINE HEATS THE ATMOSPHERE. WATER CONTENT OF THE
ATMOSPHERE IS VERY HIGH...SO RAINFALLS WILL EASILY EXCEED AN INCH
PER HOUR AND LIKELY REACH TWO INCHES AS THE STORMS MOVE AROUND 10
MPH.
CONDITIONS ARE ALSO FAVORABLE FOR FUNNEL CLOUD DEVELOPMENT. THESE
TYPES OF FUNNEL CLOUDS ARE USUALLY NOT ASSOCIATED WITH SEVERE
WEATHER...BUT STILL MAY TOUCH DOWN WITH WEAK WINDS AT THE SURFACE.
THESE FUNNEL CLOUDS ARE MORE RELATED TO WATER SPOUTS...AND USUALLY
PRODUCE WINDS LESS THAN 60 MPH.
STAY TUNED FOR MORE SPECIFIC STATEMENTS AND NOWCASTS CONCERNING LOCAL
STORMS THROUGH THE AFTERNOON.
MYERSSpecial weather statement, Aug 4, 1:38 PM CDT, 3 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-051100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 138 PM CDT TUE AUG 4 1998 HAZARD--SLOW-MOVING THUNDERSTORMS...CAPABLE OF PRODUCING UP TO 4 INCHES OF RAIN IN A COUPLE OF HOURS. AN ISOLATED FUNNEL CLOUD OR WEAK TORNADO IS ALSO POSSIBLE. AREA OF CONCERN--ALL OF CENTRAL IOWA. TIMING DETAILS--NOW THROUGH 9 PM. METEOROLOGICAL COMMENTS--A SLOW-MOVING UPPER LOW NEAR SIOUX CITY WILL MEANDER SOUTH AND EAST ACROSS IOWA OVER THE NEXT TWO DAYS. TROPICAL MOISTURE IS VERY DEEP ACROSS THE UPPER MIDWEST...SO ISOLATED AND SPORADIC HEAVY RAINS WILL OCCUR EASILY. AMOUNTS OF 1 1/2 TO 2 1/2 INCHES PER HOUR CAN OCCUR. STORMS THAT DEVELOP IN THIS ENVIRONMENT ALSO TEND TO PRODUCE FUNNEL CLOUDS...AND POSSIBLY WEAK SHORT-LIVED TORNADOES. THESE WEAK TORNAODES ARE MORE LIKE WATERSPOUTS...PRODUCING WINDS LESS THAN 80 MPH. PRECAUTIONS--EVEN THOUGH TORRENTIAL DOWNPOURS ARE LIKELY TODAY... THEY SHOULD BE RATHER ISOLATED. THE RECENT DRY WEATHER HAS MADE IT DIFFICULT TO PRODUCE FLASH FLOODING BUT SOME PONDING PROBLEMS COULD RESULT. IF FUNNEL CLOUD REPORTS ARE RECEIVED...THEY SHOULD BE WATCHED CHLOSELY. MYERS
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 4:20 PM CDT | Severe Thunderstorm Warning | DMX | Black Hawk | 30 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.