Alert archive / Iowa / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 16, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Apr 6, 1998, 5:09 PM CDT for Story County, Iowa. It was in force for 46 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
- Apr 6, 1998, 5:09 PM CDT (22:09 UTC)
- Expired
- Apr 6, 1998, 5:55 PM CDT
- In force
- 46 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Story County, IA
The radar
The Des Moines radar (KDMX), 40 km from the middle of the area, began a volume at 22:09 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, 10.2 hours before the alert went out and 250 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1197 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 172 m²/s²
- 0-3 km storm-relative helicity
- 213 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 062209 RRA
SVRDSM
IAC169-062255-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
509 PM CDT MON APR 6 1998
* SEVERE THUNDERSTORM WARNING FOR
STORY COUNTY - CENTRAL IOWA
* UNTIL 555 PM CDT
* SOME AREAS AFFECTED
AMES
ROLAND
* AT 515 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM 7 MILES SOUTHWEST
OF AMES MOVING NORTHEAST AT 30 MPH.
* THE STORM WILL BE NEAR AMES BY 520 PM CDT.
THIS IS A DANGEROUS STORM. DO NOT GO OUTDOORS.
FABWhat 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, Apr 6, 12:45 PM CDT, 4 hours 24 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-062345- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1245 PM CDT MON APR 6 1998 HAZARD--WIDELY SCATTERED THUNDERSTORMS WEST OF I35 THIS AFTERNOON AND EVENING. THE PRIMARY THREAT FROM THE THUNDERSTORMS WILL BE HAIL. IN ADDITION...A FEW STORMS MAY PRODUCE BRIEF HEAVY RAIN AND GUSTY WINDS. TIMING AND AREA OF CONCERN--BETWEEN 200 PM AND 800 PM OVER WESTERN IOWA. THE STORMS MAY MOVE INTO THE AREA FROM SOUTHEAST NEBRASKA. THUNDERSTORM COVERAGE WILL BE WIDELY SCATTERED SO MOST AREAS WILL BE DRY. METEOROLOGICAL COMMENTS--THUNDERSTORMS INCREASED LATE THIS MORNING ACROSS SOUTHEAST NEBRASKA JUST NORTH OF A WARM FRONT OVER KANSAS AND MISSOURI. THESE STORMS MAY MOVE NORTHEAST INTO IOWA THIS AFTERNOON. THE LIMITING FACTOR FOR IOWA IS INSTABILITY. THE AIRMASS MAY DESTABALIZE THIS AFTERNOON AS LOW-LEVEL MOISTURE INCREASES. PRECAUTIONS--THERE IS A SLIGHT CHANCE OF SPOTTER ACTIVATION OVER WESTERN IOWA THIS AFTERNOON AND EVENING. THE PRIMARY THREAT WOULD BE HAIL. EMERGENCY MANAGERS AND SPOTTERS OVER WESTERN IOWA SHOULD MONITOR THE WEATHER THIS AFTERNOON. JOHNSON
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 6, 2:50 PM CDT | Severe Thunderstorm Warning | DMX | Guthrie | 30 min |
| Apr 6, 4:16 PM CDT | Severe Thunderstorm Warning | DMX | Boone, Dallas | 34 min |
| Apr 6, 4:44 PM CDT | Severe Thunderstorm Warning | DMX | Boone | 31 min |
| Apr 6, 6:24 PM CDT | Tornado Warning | DMX | Calhoun, Webster | 31 min |
| Apr 6, 6:32 PM CDT | Tornado Warning | DMX | Greene | 33 min |
| Apr 6, 6:56 PM CDT | Tornado Warning | DMX | Boone, Webster | 34 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.