Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 110, NWS Omaha, NE
NWS Omaha, NE issued this severe thunderstorm warning at May 21, 1998, 7:29 PM CDT for Harrison County, Monona County, Iowa. It was in force for 61 min. 9 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, 7:29 PM CDT (00:29 UTC)
- Expired
- May 21, 1998, 8:30 PM CDT
- In force
- 61 min
- Issued by
- NWS Omaha, NE
- Area
- Whole counties
Counties Harrison County, IA, Monona County, IA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 21, 7:40 PM CDT | Thunderstorm Wind 61 | Little Sioux, IA | |
| May 21, 7:46 PM CDT | Thunderstorm Wind 61 | Little Sioux, IA | |
| May 21, 7:54 PM CDT | Hail 0.75 | Blencoe, IA | |
| May 21, 8:01 PM CDT | Thunderstorm Wind 56 | Magnolia, IA | Trees downed. |
| May 21, 8:06 PM CDT | Hail 0.75 | Woodbine, IA | |
| May 21, 8:10 PM CDT | Hail 0.75 | Logan, IA | |
| May 21, 8:10 PM CDT | Thunderstorm Wind 61 | Woodbine, IA | Many tree limbs downed. |
| May 21, 8:20 PM CDT | Thunderstorm Wind 70 | Magnolia, IA | Trees uprooted and power lines downed. |
| May 21, 8:30 PM CDT | Tornado F0 | Castana, 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, 0.5 hours before the alert went out and 73 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, 5:05 PM CDT, 2 hours 24 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093- IAZ043-055-056-069-079-080-090-091-221200- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 505 PM CDT THU MAY 21 1998 ...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA... SPOTTER ACTION... STORM SPOTTER ACTIVATION MAY BE NEEDED TONIGHT IN EASTERN NEBRASKA AND SOUTHWEST IOWA. DISCUSSION... THUNDERSTORMS WILL BE SCATTERED ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA THROUGH TONIGHT. THE CHANCE OF SEVERE STORMS IS SLIGHTLY HIGHER SOUTH OF A LINE FROM NELIGH TO TEKAMAH AND HARLAN IOWA WHERE THE ATMOSPHERE IS MORE UNSTABLE. THUNDERSTORMS WILL HAVE POTENTIAL TO PRODUCE DAMAGING WINDS AND HAIL. SIGNIFICANT RAINFALL IS ALSO POSSIBLE. > A NEARLY STATIONARY FRONT EXTENDS FROM SOUTHERN MISSOURI TO NORTHERN KANSAS AND EASTERN WYOMING. VERY MOIST AND UNSTABLE AIR SOUTH OF THE FRONT WILL CONTINUE TO BE LIFTED NORTH ACROSS NEBRASKA AND SOUTHWEST IOWA...WHILE UPPER LEVEL DISTURBANCES TRACK OVER THE AREA. MILLER
Special weather statement, May 21, 5:05 PM CDT, 2 hours 24 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093- IAZ043-055-056-069-079-080-090-091-221200- SEVERE WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 505 PM CDT THU MAY 21 1998 ...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA... SPOTTER ACTION... STORM SPOTTER ACTIVATION MAY BE NEEDED TONIGHT IN EASTERN NEBRASKA AND SOUTHWEST IOWA. DISCUSSION... THUNDERSTORMS WILL BE SCATTERED ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA THROUGH TONIGHT. THE CHANCE OF SEVERE STORMS IS SLIGHTLY HIGHER SOUTH OF A LINE FROM NELIGH TO TEKAMAH AND HARLAN IOWA WHERE THE ATMOSPHERE IS MORE UNSTABLE. THUNDERSTORMS WILL HAVE POTENTIAL TO PRODUCE DAMAGING WINDS AND HAIL. SIGNIFICANT RAINFALL IS ALSO POSSIBLE. > A NEARLY STATIONARY FRONT EXTENDS FROM SOUTHERN MISSOURI TO NORTHERN KANSAS AND EASTERN WYOMING. VERY MOIST AND UNSTABLE AIR SOUTH OF THE FRONT WILL CONTINUE TO BE LIFTED NORTH ACROSS NEBRASKA AND SOUTHWEST IOWA...WHILE UPPER LEVEL DISTURBANCES TRACK OVER THE AREA. MILLER
The office that day
Everything else NWS Omaha, NE issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 21, 7:47 PM CDT | Severe Thunderstorm Warning | OAX | Burt | 18 min |
| May 21, 10:47 PM CDT | Severe Thunderstorm Warning | OAX | Butler, Seward | 63 min |
| May 21, 11:23 PM CDT | Severe Thunderstorm Warning | OAX | Lancaster, Saunders | 62 min |
| May 22, 12:02 AM CDT | Tornado Warning | OAX | Lancaster | 33 min |
| May 22, 12:11 AM CDT | Flash Flood Warning | OAX | Butler, Seward | 6 hr |
| May 22, 12:16 AM CDT | Tornado Warning | OAX | Lancaster | 19 min |
| May 22, 12:19 AM CDT | Severe Thunderstorm Warning | OAX | Sarpy | 46 min |
| May 22, 12:38 AM CDT | Severe Thunderstorm Warning | OAX | Cass | 62 min |
| May 22, 12:44 AM CDT | Severe Thunderstorm Warning | OAX | Saunders | 16 min |
| May 22, 12:46 AM CDT | Flash Flood Warning | OAX | Lancaster, Saunders | 5 hr |
| May 22, 12:56 AM CDT | Severe Thunderstorm Warning | OAX | Saline | 64 min |
| May 22, 1:04 AM CDT | Severe Thunderstorm Warning | OAX | Sarpy | 46 min |
| May 22, 1:48 AM CDT | Severe Thunderstorm Warning | OAX | Gage, Lancaster | 62 min |
| May 21, 7:50 PM CDT | Tornado Warning | OAX | Harrison, Monona | 50 min |
| May 21, 8:47 PM CDT | Tornado Warning | OAX | Pottawattamie | 33 min |
| May 22, 2:36 AM CDT | Severe Thunderstorm Warning | OAX | Page | 64 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.