Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 135, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at May 28, 1998, 8:20 PM CDT for Sac County, Iowa. It was in force for 20 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 28, 1998, 8:20 PM CDT (01:20 UTC)
- Expired
- May 28, 1998, 8:40 PM CDT
- In force
- 20 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Sac County, IA
The radar
The Des Moines radar (KDMX), 135 km from the middle of the area, began a volume at 01:22 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 28, 4:00 PM CDT | Tornado Watch | SPC | 5 hr |
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 1.3 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
- 2835 J/kg
- Mixed-layer CIN
- -9 J/kg
- Mixed-layer LCL
- 1954 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 115 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 7.5
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 28, 7:49 PM CDT, 31 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-291100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 749 PM CDT THU MAY 28 1998 HAZARD--SCATTERED THUNDERSTORMS...SOME POSSIBLY SEVERE AND CAPABLE OF PRODUCING ISOLATED TORNADOES...LARGE HAIL AND DAMAGING WINDS. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH SOME AREAS SEEING BETWEEN 1 AND 3 INCHES OF RAIN IN A SHORT TIME. AREAS OF CONCERN AND TIMING DETAILS--THROUGH 9 PM THE THREAT OF SEVERE WEATHER WILL BE OVER THE NORTHERN HALF OF IOWA...MAINLY ALONG AND NORTH OF HIGHWAY 20. AFTER 9 PM THE THREAT OF SEVERE WEATHER WILL SHIFT INTO AREAS FARTHER SOUTH...MAINLY SOUTH OF HIGHWAY 20 AND NORTH OF HIGHWAY 92. ADDITIONAL WATCHES MAY BE ISSUED IN IOWA THIS EVENING. METEOROLOGICAL COMMENTS--A COLD FRONT REMAINS ACROSS THE NORTHERN THIRD OF IOWA THIS EVENING. MOISTURE CONTINUES TO POOL ALONG THIS BOUNDARY WITH DEW POINTS IN THE MID 60S TO LOWER 70S ACROSS THE STATE. THE ATMOSPHERE REMAINS VERY UNSTABLE WITH LIFTED INDICES IN THE -6 TO -10 RANGE. THIS INSTABILITY INDICATES THE POTENTIAL FOR ISOLATED TORNADOES AND SEVERE STORMS. THE FIRST ROUND OF STORMS THAT DEVELOPED ALONG THE FRONTAL BOUNDARY LATE THIS AFTERNOON PRODUCED AN OUTFLOW BOUNDARY THAT MOVED SOUTH INTO CENTRAL IOWA AND EXTENDS BACK INTO NORTHWEST IOWA WHERE ADDITIONAL THUNDERSTORMS HAVE DEVELOPED. SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG THIS BOUNDARY TONIGHT. PRECAUTIONS--EMERGENCY MANAGERS AND SPOTTERS SHOULD CONTINUE TO MONITOR THE WEATHER SITUATION THIS EVENING. DEPLOYMENT OF SPOTTERS IN CENTRAL IOWA MAY BE NEEDED AFTER 9 PM OR SO. CONDITIONS REMAIN FAVORABLE THIS EVENING FOR SEVERE THUNDERSTORMS AND VERY HEAVY RAINFALL. STARK
Special weather statement, May 28, 7:49 PM CDT, 31 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-291100- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 749 PM CDT THU MAY 28 1998 HAZARD--SCATTERED THUNDERSTORMS...SOME POSSIBLY SEVERE AND CAPABLE OF PRODUCING ISOLATED TORNADOES...LARGE HAIL AND DAMAGING WINDS. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH SOME AREAS SEEING BETWEEN 1 AND 3 INCHES OF RAIN IN A SHORT TIME. AREAS OF CONCERN AND TIMING DETAILS--THROUGH 9 PM THE THREAT OF SEVERE WEATHER WILL BE OVER THE NORTHERN HALF OF IOWA...MAINLY ALONG AND NORTH OF HIGHWAY 20. AFTER 9 PM THE THREAT OF SEVERE WEATHER WILL SHIFT INTO AREAS FARTHER SOUTH...MAINLY SOUTH OF HIGHWAY 20 AND NORTH OF HIGHWAY 92. ADDITIONAL WATCHES MAY BE ISSUED IN IOWA THIS EVENING. METEOROLOGICAL COMMENTS--A COLD FRONT REMAINS ACROSS THE NORTHERN THIRD OF IOWA THIS EVENING. MOISTURE CONTINUES TO POOL ALONG THIS BOUNDARY WITH DEW POINTS IN THE MID 60S TO LOWER 70S ACROSS THE STATE. THE ATMOSPHERE REMAINS VERY UNSTABLE WITH LIFTED INDICES IN THE -6 TO -10 RANGE. THIS INSTABILITY INDICATES THE POTENTIAL FOR ISOLATED TORNADOES AND SEVERE STORMS. THE FIRST ROUND OF STORMS THAT DEVELOPED ALONG THE FRONTAL BOUNDARY LATE THIS AFTERNOON PRODUCED AN OUTFLOW BOUNDARY THAT MOVED SOUTH INTO CENTRAL IOWA AND EXTENDS BACK INTO NORTHWEST IOWA WHERE ADDITIONAL THUNDERSTORMS HAVE DEVELOPED. SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG THIS BOUNDARY TONIGHT. PRECAUTIONS--EMERGENCY MANAGERS AND SPOTTERS SHOULD CONTINUE TO MONITOR THE WEATHER SITUATION THIS EVENING. DEPLOYMENT OF SPOTTERS IN CENTRAL IOWA MAY BE NEEDED AFTER 9 PM OR SO. CONDITIONS REMAIN FAVORABLE THIS EVENING FOR SEVERE THUNDERSTORMS AND VERY HEAVY RAINFALL. STARK
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 28, 8:24 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun | 36 min |
| May 28, 8:57 PM CDT | Severe Thunderstorm Warning | DMX | Calhoun, Webster | 33 min |
| May 28, 9:22 PM CDT | Tornado Warning | DMX | Crawford | 33 min |
| May 28, 9:29 PM CDT | Severe Thunderstorm Warning | DMX | Webster | 36 min |
| May 28, 9:41 PM CDT | Severe Thunderstorm Warning | DMX | Boone | 34 min |
| May 28, 9:52 PM CDT | Tornado Warning | DMX | Crawford | 33 min |
| May 28, 10:15 PM CDT | Severe Thunderstorm Warning | DMX | Story | 50 min |
| May 28, 10:21 PM CDT | Tornado Warning | DMX | Carroll, Crawford | 39 min |
| May 28, 10:21 PM CDT | Tornado Warning | DMX | Carroll, Crawford | 34 min |
| May 28, 10:40 PM CDT | Severe Thunderstorm Warning | DMX | Marshall | 50 min |
| May 28, 10:46 PM CDT | Severe Thunderstorm Warning | DMX | Crawford | 34 min |
| May 28, 10:50 PM CDT | Severe Thunderstorm Warning | DMX | Carroll | 35 min |
| May 28, 11:04 PM CDT | Tornado Warning | DMX | Carroll | 36 min |
| May 28, 11:10 PM CDT | Tornado Warning | DMX | Audubon | 35 min |
| May 28, 11:25 PM CDT | Tornado Warning | DMX | Greene, Guthrie | 35 min |
| May 28, 11:44 PM CDT | Tornado Warning | DMX | Audubon, Guthrie | 36 min |
| May 28, 11:59 PM CDT | Tornado Warning | DMX | Dallas, Guthrie | 51 min |
| May 29, 12:09 AM CDT | Severe Thunderstorm Warning | DMX | Audubon | 36 min |
| May 29, 12:24 AM CDT | Tornado Warning | DMX | Guthrie | 26 min |
| May 29, 12:33 AM CDT | Severe Thunderstorm Warning | DMX | Cass | 32 min |
| May 29, 12:50 AM CDT | Severe Thunderstorm Warning | DMX | Adair, Dallas, Guthrie | 50 min |
| May 29, 1:24 AM CDT | Severe Thunderstorm Warning | DMX | Cass | 31 min |
| May 29, 2:01 AM CDT | Severe Thunderstorm Warning | DMX | Adams | 34 min |
| May 29, 2:01 AM CDT | Severe Thunderstorm Warning | DMX | Adams | 39 min |
| May 29, 2:21 AM CDT | Severe Thunderstorm Warning | DMX | Adair, Union | 49 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.