Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 105, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 21, 1998, 11:01 PM CDT for Decatur County, Iowa. It was in force for 44 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
- May 21, 1998, 11:01 PM CDT (04:01 UTC)
- Expired
- May 21, 1998, 11:45 PM CDT
- In force
- 44 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Decatur County, IA
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 21, 11:00 PM CDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 4.0 hours before the alert went out and 226 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, 7:16 PM CDT, 3 hours 45 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, 3 hours 45 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, 3 hours 44 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, 9:29 PM CDT | Severe Thunderstorm Warning | DMX | Adair, Guthrie | 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, 11:03 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; the sounding from the Mesonet's radiosonde archive.