Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 98, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 15, 1997, 12:49 AM CDT for Polk County, Story 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
- Aug 15, 1997, 12:49 AM CDT (05:49 UTC)
- Expired
- Aug 15, 1997, 1:20 AM CDT
- In force
- 31 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Polk County, IA, Story County, IA
The radar
The Des Moines radar (KDMX), 22 km from the middle of the area, began a volume at 05:51 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 15, 1:10 AM CDT | Thunderstorm Wind 61 | Roland, IA | |
| Aug 15, 1:20 AM CDT | Thunderstorm Wind 50 | Des Moines, 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, 5.8 hours before the alert went out and 245 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
- 1810 J/kg
- Mixed-layer CIN
- -28 J/kg
- Mixed-layer LCL
- 837 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 101 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.5
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDSM 150549 RRA
SVRDSM
IAC153-169-150620-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1249 AM CDT FRI AUG 15 1997
* SEVERE THUNDERSTORM WARNING FOR
NORTHERN POLK COUNTY - CENTRAL IOWA
SOUTHERN STORY COUNTY - CENTRAL IOWA
* UNTIL 120 AM CDT
* SOME AREAS AFFECTED
ANKENY
HUXLEY
SLATER
AMES
* AT 1247 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM NEAR WOODWARD OR
25 MILES NORTHWEST OF DES MOINES MOVING EAST AT 40 MPH.
* THE STORM WILL CONTINUE TO MOVE ALONG THE POLK AND STORY COUNTY LINE
AND WILL BE NEAR SLATER BY 1258 AM AND NEAR HUXLEY BY 105 AM.
THIS IS A DANGEROUS STORM. DO NOT GO OUTDOORS.
KUBINAWhat 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, Aug 14, 9:09 PM CDT, 3 hours 40 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-150900- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 910 PM CDT THU AUG 14 1997 HAZARD--ISOLATED SEVERE THUNDERSTORMS. AREA OF CONCERN AND TIMING DETAILS--WEST OF AN ESTHERVILLE TO ATLANTIC LINE BY MIDNIGHT AND OVER THE REMAINDER OF CENTRAL IOWA DURING THE EARLY MORNING HOURS. METEOROLOGICAL COMMENTS--THE THREAT FOR SEVERE WEATHER CONTINUES... ESPECIALLY OVER EXTREME WESTERN IOWA. SEVERE THUNDERSTORMS HAVE DEVELOPED OVER PORTIONS OF SOUTH DAKOTA AND NEBRASKA THIS EVENING ALONG A SURFACE TROUGH. THESE STORMS ARE EXPECTED TO MOVE INTO WESTERN IOWA BY MIDNIGHT. ABUNDANT LOW MOISTURE REMAINS IN PLACE WITH SURFACE DEW POINTS IN THE 70S AND LIFT INDICES NOW AS LOW AS MINUS TEN. IN ADDITION...STRONG WARM AIR ADVECTION CONTINUES AT THE 5000 FOOT LEVEL IN THE ATMOSPHERE. ALSO...A 40 KNOT LOW LEVEL JET STREAM IS FORECAST TO DEVELOP DURING THE NEXT COUPLE OF HOURS. WORKING AGAINST A WIDESPREAD SEVERE WEATHER EPISODE IN IOWA WILL BE MARGINAL UPPER LEVEL SUPPORT. SOME DECREASE IN STORM INTENSITY IS LIKELY AS THE STORMS IN NEBRASKA CROSS THE MISSOURI RIVER. AT THIS TIME IT APPEARS THAT MAIN THREAT TONIGHT IN CENTRAL IOWA WILL BE FROM HEAVY RAIN AND WIND GUSTS TO 45 MPH. THE STORMS IN NEBRASKA HAVE A HISTORY OF PRODUCING HAIL AS LARGE AS TENNIS BALLS AND IT IS POSSIBLE THAT A FEW STORMS MAY REACH SEVERE LIMITS...ESPECfIALLY OVER WESTERN IOWA. PRECAUTIONS--EMERGENCY MANAGEMENT AND SPOTTER GROUPS SHOULD CONTINUE TO MONITOR THIS RAPIDLY CHANGING WEATHER SITUATION AS IT DEVELOPS. KUBINA
Special weather statement, Aug 14, 9:10 PM CDT, 3 hours 39 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-150900- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 910 PM CDT THU AUG 14 1997 HAZARD--ISOLATED SEVERE THUNDERSTORMS. AREA OF CONCERN AND TIMING DETAILS--WEST OF AN ESTHERVILLE TO ATLANTIC LINE BY MIDNIGHT AND OVER THE REMAINDER OF CENTRAL IOWA DURING THE EARLY MORNING HOURS. METEOROLOGICAL COMMENTS--THE THREAT FOR SEVERE WEATHER CONTINUES... ESPECIALLY OVER EXTREME WESTERN IOWA. SEVERE THUNDERSTORMS HAVE DEVELOPED OVER PORTIONS OF SOUTH DAKOTA AND NEBRASKA THIS EVENING ALONG A SURFACE TROUGH. THESE STORMS ARE EXPECTED TO MOVE INTO WESTERN IOWA BY MIDNIGHT. ABUNDANT LOW MOISTURE REMAINS IN PLACE WITH SURFACE DEW POINTS IN THE 70S AND LIFT INDICES NOW AS LOW AS MINUS TEN. IN ADDITION...STRONG WARM AIR ADVECTION CONTINUES AT THE 5000 FOOT LEVEL IN THE ATMOSPHERE. ALSO...A 40 KNOT LOW LEVEL JET STREAM IS FORECAST TO DEVELOP DURING THE NEXT COUPLE OF HOURS. WORKING AGAINST A WIDESPREAD SEVERE WEATHER EPISODE IN IOWA WILL BE MARGINAL UPPER LEVEL SUPPORT. SOME DECREASE IN STORM INTENSITY IS LIKELY AS THE STORMS IN NEBRASKA CROSS THE MISSOURI RIVER. AT THIS TIME IT APPEARS THAT MAIN THREAT TONIGHT IN CENTRAL IOWA WILL BE FROM HEAVY RAIN AND WIND GUSTS TO 45 MPH. THE STORMS IN NEBRASKA HAVE A HISTORY OF PRODUCING HAIL AS LARGE AS TENNIS BALLS AND IT IS POSSIBLE THAT A FEW STORMS MAY REACH SEVERE LIMITS...ESPECIALLY OVER WESTERN IOWA. PRECAUTIONS--EMERGENCY MANAGEMENT AND SPOTTER GROUPS SHOULD CONTINUE TO MONITOR THIS RAPIDLY CHANGING WEATHER SITUATION AS IT DEVELOPS. KUBINA
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 14, 11:00 PM CDT | Severe Thunderstorm Warning | DMX | Crawford | 35 min |
| Aug 14, 11:58 PM CDT | Severe Thunderstorm Warning | DMX | Carroll, Greene | 47 min |
| Aug 15, 12:23 AM CDT | Severe Thunderstorm Warning | DMX | Boone | 27 min |
| Aug 15, 12:31 AM CDT | Tornado Warning | DMX | Boone, Dallas | 34 min |
| Aug 15, 12:59 AM CDT | Severe Thunderstorm Warning | DMX | Hamilton, Story | 36 min |
Nearby
Severe Thunderstorm Warnings in Iowa, 1997Every severe thunderstorm warning in 1997
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; radar from the NEXRAD Level II archive.