Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 100, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 21, 1998, 9:29 PM CDT for Adair County, Guthrie County, Iowa. It was in force for 31 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
- May 21, 1998, 9:29 PM CDT (02:29 UTC)
- Expired
- May 21, 1998, 10:00 PM CDT
- In force
- 31 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Adair County, IA, Guthrie County, IA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 21, 9:45 PM CDT | Thunderstorm Wind 70 | Fontanelle, IA | |
| May 21, 9:50 PM CDT | Thunderstorm Wind 61 | Bridgewater, 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 nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 2.5 hours before the alert went out and 158 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
- 66 J/kg
- Mixed-layer CIN
- -295 J/kg
- Mixed-layer LCL
- 905 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- 300 m²/s²
- 0-3 km storm-relative helicity
- 484 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 7.6
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 21, 3:37 PM CDT, 5 hours 52 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-220230- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 337 PM CDT THU MAY 21 1998 HAZARD--SCATTERED THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL... HEAVY RAINFALL AND ISOLATED STRONG WIND GUSTS. AREA OF CONCERN--SOUTHWESTERN QUARTER OF IOWA...SOUTHWEST OF AN AUDUBON TO OTTUMWA LINE. TIMING DETAILS--FROM 200 AM TO 800 AM FRIDAY MORNING. METEOROLOGICAL COMMENTS-- A STATIONARY FRONT LYING ACROSS PARTS OF MISSOURI AND KANSAS WILL ACT AS THE FOCUS FOR THUNDERSTORM DEVELOPMENT OVER THE NEXT 24 HOURS. ONE COMPLEX OF STORMS HAS MOVED ACROSS PARTS OF EXTREME SOUTHWEST IOWA INTO MISSOURI THIS AFTERNOON WITH ADDITIONAL THUNDERSTORMS DEVELOPING ACROSS NEBRASKA. A BAND OF LIGHTER SHOWERS WAS PUSHING ACROSS WESTERN IOWA LATE THIS AFTERNOON BUT THESE APPEAR TO BE WEAKENING AS THEY TRACK EAST. THE THUNDERSTORMS DEVELOPING OVER WEST CENTRAL NEBRASKA WILL CONTINUE TO PUSH EAST THIS EVENING AND GRADUALLY WORK THEIR WAY INTO SOUTHWEST IOWA LATE TONIGHT AND DURING THE MORNING HOURS ON FRIDAY. THE BEST INSTABILITY IS EXPECTED TO REMAIN JUST SOUTH OF THE STATE OVERNIGHT...HOWEVER LATEST SATELLITE PICTURES INDICATE A PLUME OF TROPICAL MOISTURE WORKING ITS WAY ACROSS THE SOUTHERN PLAINS INTO THE KANSAS AND EVENTUALLY INTO SOUTHERN NEBRASKA BY THIS EVENING. THIS ADDITIONAL MOISTURE FEED WILL LIKELY AID IN PRODUCING EXCESSIVE RAINFALL AMOUNTS OVER PARTS OF NEBRASKA THIS EVENING AND EVENTUALLY INTO SOUTHWEST IOWA LATE TONIGHT INTO FRIDAY MORNING. AS A RESULT...IT APPEARS THE PRIMARY THREAT FROM THESE STORMS TONIGHT WILL BE FROM HEAVY RAINFALL AS WELL AS LARGE HAIL. A FEW STORMS MAY PRODUCE STRONG STRAIGHT LINE WIND GUSTS AS THEY RACE SOUTHEAST OUT OF NEBRASKA LATER TONIGHT AS WELL. FURTHER NORTH...SHOWERS AND THUNDERSTORMS WILL DIMINISH IN INTENSITY AS WELL AS AREAL COVERAGE AS ONE HEADS NORTH OF I80. PRECAUTIONS--EMERGENCY MANAGERS...ESPECIALLY OVER SOUTHWEST IOWA... NEED TO BE ON THE ALERT FOR THE THREAT OF ADDITIONAL HEAVY RAINFALL LATE TONIGHT INTO FRIDAY MORNING. ADDITIONAL STATEMENTS ON THIS THUNDERSTORM THREAT FOR SOUTHWEST IOWA WILL BE ISSUED DURING THE EVENING HOURS. SMITH
Special weather statement, May 21, 3:37 PM CDT, 5 hours 52 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-220230- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 337 PM CDT THU MAY 21 1998 HAZARD--SCATTERED THUNDERSTORMS CAPABLE OF PRODUCING LARGE HAIL... HEAVY RAINFALL AND ISOLATED STRONG WIND GUSTS. AREA OF CONCERN--SOUTHWESTERN QUARTER OF IOWA...SOUTHWEST OF AN AUDUBON TO OTTUMWA LINE. TIMING DETAILS--FROM 200 AM TO 800 AM FRIDAY MORNING. METEOROLOGICAL COMMENTS-- A STATIONARY FRONT LYING ACROSS PARTS OF MISSOURI AND KANSAS WILL ACT AS THE FOCUS FOR THUNDERSTORM DEVELOPMENT OVER THE NEXT 24 HOURS. ONE COMPLEX OF STORMS HAS MOVED ACROSS PARTS OF EXTREME SOUTHWEST IOWA INTO MISSOURI THIS AFTERNOON WITH ADDITIONAL THUNDERSTORMS DEVELOPING ACROSS NEBRASKA. A BAND OF LIGHTER SHOWERS WAS PUSHING ACROSS WESTERN IOWA LATE THIS AFTERNOON BUT THESE APPEAR TO BE WEAKENING AS THEY TRACK EAST. THE THUNDERSTORMS DEVELOPING OVER WEST CENTRAL NEBRASKA WILL CONTINUE TO PUSH EAST THIS EVENING AND GRADUALLY WORK THEIR WAY INTO SOUTHWEST IOWA LATE TONIGHT AND DURING THE MORNING HOURS ON FRIDAY. THE BEST INSTABILITY IS EXPECTED TO REMAIN JUST SOUTH OF THE STATE OVERNIGHT...HOWEVER LATEST SATELLITE PICTURES INDICATE A PLUME OF TROPICAL MOISTURE WORKING ITS WAY ACROSS THE SOUTHERN PLAINS INTO THE KANSAS AND EVENTUALLY INTO SOUTHERN NEBRASKA BY THIS EVENING. THIS ADDITIONAL MOISTURE FEED WILL LIKELY AID IN PRODUCING EXCESSIVE RAINFALL AMOUNTS OVER PARTS OF NEBRASKA THIS EVENING AND EVENTUALLY INTO SOUTHWEST IOWA LATE TONIGHT INTO FRIDAY MORNING. AS A RESULT...IT APPEARS THE PRIMARY THREAT FROM THESE STORMS TONIGHT WILL BE FROM HEAVY RAINFALL AS WELL AS LARGE HAIL. A FEW STORMS MAY PRODUCE STRONG STRAIGHT LINE WIND GUSTS AS THEY RACE SOUTHEAST OUT OF NEBRASKA LATER TONIGHT AS WELL. FURTHER NORTH...SHOWERS AND THUNDERSTORMS WILL DIMINISH IN INTENSITY AS WELL AS AREAL COVERAGE AS ONE HEADS NORTH OF I80. PRECAUTIONS--EMERGENCY MANAGERS...ESPECIALLY OVER SOUTHWEST IOWA... NEED TO BE ON THE ALERT FOR THE THREAT OF ADDITIONAL HEAVY RAINFALL LATE TONIGHT INTO FRIDAY MORNING. ADDITIONAL STATEMENTS ON THIS THUNDERSTORM THREAT FOR SOUTHWEST IOWA WILL BE ISSUED DURING THE EVENING HOURS. SMITH
Special weather statement, May 21, 7:16 PM CDT, 2 hours 13 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-221100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 716 PM CDT THU MAY 21 1998 HAZARD--SCATTERED THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN...STRONG WIND GUSTS AND LARGE HAIL. TIMING DETAILS AND AREA OF CONCERN--THE WESTERN QUARTER OF IOWA THROUGH 10 PM AND THE SOUTHERN TWO TIERS OF IOWA COUNTIES FROM 10 PM TO MIDNIGHT. AN ADDITIONAL THREAT FOR REDEVELOPMENT OF STORMS TOWARDS DAYBREAK. METEOROLOGICAL COMMENTS-- THUNDERSTORMS HAVE DEVELOPED ALONG A BOUNDARY OVER NORTHEASTERN NEBRASKA DURING THE LATE AFTERNOON HOURS. THESE STORMS WILL BE MOVING INTO FAR WESTERN IOWA BY 8 PM AND THEN ACROSS THE WESTERN QUARTER OF THE WARNING AREA BEFORE HEADING TO THE SOUTHEAST. THE STORMS WILL COVER A CORRIDOR FROM ABOUT STORM LAKE TO DENISON...MOVING EAST TO ROUGHLY WEBSTER CITY THEN HEAD SOUTHEAST TOWARDS CHARITON AND OTTUMWA LATER THIS EVENING. THESE STORMS HAD A HISTORY OF PRODUCING STRONG WIND AND LARGE HAIL IN NEBRASKA BUT THEY ARE MOVING INTO A LESS FAVORABLE ENVIRONMENT AS THEY CROSS THE MISSOURI RIVER. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN WITH LOCAL AREAS EXPERIENCING STRONG WIND GUSTS AND HAIL. A SECONDARY COMPLEX OF STORMS OVER CENTRAL NEBRASKA WILL MAKE ITS WAY INTO IOWA OVERNIGHT AND ESSENTIALLY MOVE OVER THE SAME AREA WITH THE MAIN THREAT ONCE AGAIN BEING HEAVY RAIN. PRECAUTIONS--EMERGENCY MANAGERS...ESPECIALLY OVER SOUTHWEST IOWA... NEED TO BE ON THE ALERT FOR THE THREAT OF ADDITIONAL HEAVY RAINFALL TONIGHT AND AGAIN TOWARDS DAYBREAK ON FRIDAY. FAB
Special weather statement, May 21, 7:16 PM CDT, 2 hours 13 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-221100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 716 PM CDT THU MAY 21 1998 HAZARD--SCATTERED THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN...STRONG WIND GUSTS AND LARGE HAIL. TIMING DETAILS AND AREA OF CONCERN--THE WESTERN QUARTER OF IOWA THROUGH 10 PM AND THE SOUTHERN TWO TIERS OF IOWA COUNTIES FROM 10 PM TO MIDNIGHT. AN ADDITIONAL THREAT FOR REDEVELOPMENT OF STORMS TOWARDS DAYBREAK. METEOROLOGICAL COMMENTS-- THUNDERSTORMS HAVE DEVELOPED ALONG A BOUNDARY OVER NORTHEASTERN NEBRASKA DURING THE LATE AFTERNOON HOURS. THESE STORMS WILL BE MOVING INTO FAR WESTERN IOWA BY 8 PM AND THEN ACROSS THE WESTERN QUARTER OF THE WARNING AREA BEFORE HEADING TO THE SOUTHEAST. THE STORMS WILL COVER A CORRIDOR FROM ABOUT STORM LAKE TO DENISON...MOVING EAST TO ROUGHLY WEBSTER CITY THEN HEAD SOUTHEAST TOWARDS CHARITON AND OTTUMWA LATER THIS EVENING. THESE STORMS HAD A HISTORY OF PRODUCING STRONG WIND AND LARGE HAIL IN NEBRASKA BUT THEY ARE MOVING INTO A LESS FAVORABLE ENVIRONMENT AS THEY CROSS THE MISSOURI RIVER. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN WITH LOCAL AREAS EXPERIENCING STRONG WIND GUSTS AND HAIL. A SECONDARY COMPLEX OF STORMS OVER CENTRAL NEBRASKA WILL MAKE ITS WAY INTO IOWA OVERNIGHT AND ESSENTIALLY MOVE OVER THE SAME AREA WITH THE MAIN THREAT ONCE AGAIN BEING HEAVY RAIN. PRECAUTIONS--EMERGENCY MANAGERS...ESPECIALLY OVER SOUTHWEST IOWA... NEED TO BE ON THE ALERT FOR THE THREAT OF ADDITIONAL HEAVY RAINFALL TONIGHT AND AGAIN TOWARDS DAYBREAK ON FRIDAY. FAB
Special weather statement, May 21, 7:17 PM CDT, 2 hours 12 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-221100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 717 PM CDT THU MAY 21 1998 HAZARD--SCATTERED THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN...STRONG WIND GUSTS AND LARGE HAIL. TIMING DETAILS AND AREA OF CONCERN--THE WESTERN QUARTER OF IOWA THROUGH 10 PM AND THE SOUTHERN TWO TIERS OF IOWA COUNTIES FROM 10 PM TO MIDNIGHT. THERE IS ALSO AN ADDITIONAL THREAT FOR REDEVELOPMENT OF STORMS TOWARDS DAYBREAK. METEOROLOGICAL COMMENTS-- THUNDERSTORMS HAVE DEVELOPED ALONG A BOUNDARY OVER NORTHEASTERN NEBRASKA DURING THE LATE AFTERNOON HOURS. THESE STORMS WILL BE MOVING INTO FAR WESTERN IOWA BY 8 PM AND THEN ACROSS THE WESTERN QUARTER OF THE WARNING AREA BEFORE HEADING TO THE SOUTHEAST. THE STORMS WILL COVER A CORRIDOR FROM ABOUT STORM LAKE TO DENISON...MOVING EAST TO ROUGHLY WEBSTER CITY THEN HEAD SOUTHEAST TOWARDS CHARITON AND OTTUMWA LATER THIS EVENING. THESE STORMS HAD A HISTORY OF PRODUCING STRONG WIND AND LARGE HAIL IN NEBRASKA BUT THEY ARE MOVING INTO A LESS FAVORABLE ENVIRONMENT AS THEY CROSS THE MISSOURI RIVER. THE MAIN THREAT FROM THESE STORMS WILL BE HEAVY RAIN WITH LOCAL AREAS EXPERIENCING STRONG WIND GUSTS AND HAIL. A SECONDARY COMPLEX OF STORMS OVER CENTRAL NEBRASKA WILL MAKE ITS WAY INTO IOWA OVERNIGHT AND ESSENTIALLY MOVE OVER THE SAME AREA WITH THE MAIN THREAT ONCE AGAIN BEING HEAVY RAIN. PRECAUTIONS--EMERGENCY MANAGERS...ESPECIALLY OVER SOUTHWEST IOWA... NEED TO BE ON THE ALERT FOR THE THREAT OF ADDITIONAL HEAVY RAINFALL TONIGHT AND AGAIN TOWARDS DAYBREAK ON FRIDAY. FAB
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 21, 8:54 PM CDT | Severe Thunderstorm Warning | DMX | Audubon, Cass | 31 min |
| May 21, 10:04 PM CDT | Severe Thunderstorm Warning | DMX | Dallas, Madison | 41 min |
| May 21, 10:13 PM CDT | Severe Thunderstorm Warning | DMX | Union | 47 min |
| May 21, 10:32 PM CDT | Severe Thunderstorm Warning | DMX | Clarke | 48 min |
| May 21, 10:45 PM CDT | Severe Thunderstorm Warning | DMX | Warren | 50 min |
| May 21, 11:01 PM CDT | Severe Thunderstorm Warning | DMX | Decatur | 44 min |
| May 21, 11:03 PM CDT | Severe Thunderstorm Warning | DMX | Lucas | 47 min |
| May 21, 11:17 PM CDT | Severe Thunderstorm Warning | DMX | Wayne | 48 min |
| May 21, 11:26 PM CDT | Severe Thunderstorm Warning | DMX | Marion | 49 min |
| May 21, 11:51 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Monroe | 49 min |
| May 22, 12:27 AM CDT | Severe Thunderstorm Warning | DMX | Davis | 48 min |
| May 22, 1:53 AM CDT | Severe Thunderstorm Warning | DMX | Adair | 32 min |
| May 22, 2:15 AM CDT | Severe Thunderstorm Warning | DMX | Madison | 45 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.