Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 103, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Aug 16, 1997, 8:58 PM CDT for Polk County, Iowa. It was in force for 32 min. 1 report 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 16, 1997, 8:58 PM CDT (01:58 UTC)
- Expired
- Aug 16, 1997, 9:30 PM CDT
- In force
- 32 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Polk County, IA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 16, 9:26 PM CDT | Hail 0.75 | 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, 2.0 hours before the alert went out and 236 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
- 1159 J/kg
- Mixed-layer CIN
- -284 J/kg
- Mixed-layer LCL
- 1161 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 96 m²/s²
- 0-3 km storm-relative helicity
- 245 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 18.2
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDSM 170157 RRA
SVRDSM
IAC153-170230-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
858 PM CDT SAT AUG 16 1997
* SEVERE THUNDERSTORM WARNING FOR
SOUTHEASTERN POLK COUNTY - CENTRAL IOWA
* UNTIL 930 PM CDT
* SOME AREAS AFFECTED
PLEASANT HILL
ALTOONA
IOWA STATE FAIRGROUNDS
* AT 855 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM NEAR IOWA STATE
FAIRGROUNDS MOVING NORTHEAST AT 10 TO 15 MPdH.
* THE STORM WILL BE BY PLEASANT HILL BY 905 PM CDT.
THIS IS A DANGEROUS STORM. DO NOT GO OUTDOORS.
FORSTER/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 16, 3:32 PM CDT, 5 hours 26 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-171200- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 332 PM CDT SAT AUG 16 1997 HAZARD--SCATTERED EVENING SEVERE THUNDERSTORMS WITH DAMAGING WIND THE PRIMARY CONCERN. AREA OF CONCERN AND TIMING--SOUTH OF AN ATLANTIC-DUBUQUE LINE AFTER 6 OR 7 PM. METEOROLOGICAL COMMENTS--MOST OF SOUTHERN IOWA REMAINS QUITE UNSTABLE WITH LIFTED INDICES AROUND -10 DEGREES AND SATELLITE MEASURED CAPES OF 3000-4000 J/KG. A DEWPOINT FRONT LYING ALONG A DUBUQUE-DES MOINES- ATLANTIC LINE MAY ACT AS A FOCUS FOR THUNDERSTORMS DEVELOPMENT THIS EVENING. THE BEST LOW LEVELING FORCING REMAINS IN NORTHEAST KANSAS HOWEVER WHERE STRONGER LOW LEVEL WINDS ARE IMPINGING THE DEWPOINT FRONT. A WEAK UPPER LEVEL DISTURBANCE IS NEARING THIS AREA FROM WESTERN KANSAS NOW...WHICH MAY INDUCE THUNDERSTORMS TO DEVELOP. PRECIPITABLE WATER VALUES ARE NEAR 2 INCHES SOUTH OF THE FRONT...SO RAINFALL WILL BE INTENSE IN LOCALIZED AREAS. THE THREAT OF STRONG DAMAGING WINDS HAS LESSENED A BIT FROM EARLIER TODAY BUT WINDS TO 70 MPH COULD OCCUR. BETWEEN SUNSET AND MIDNIGHT THE WEATHER THREAT WILL BE REPEAT HEAVY RAINS OVER THE SAME AREA. RAINFALL AMOUNTS COULD EASILY EXCEED 3-4 INCHES IN SMALL AREAS BETWEEN 10 PM AND 3 AM. PRECAUTIONS--PEOPLE WITH OUTDOOR PLANS SHOULD STAY ABREAST OF THE WEATHER THIS EVENING...AND BE PREPARED TO CHANGE PLANS. SPOTTER ACTIVATION COULD BE NEEDED SOUTH OF AN ATLANTIC-DUBUQUE LINE. MYERS
Special weather statement, Aug 16, 3:33 PM CDT, 5 hours 25 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-171200- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 332 PM CDT SAT AUG 16 1997 HAZARD--SCATTERED EVENING SEVERE THUNDERSTORMS WITH DAMAGING WIND THE PRIMARY CONCERN. AREA OF CONCERN AND TIMING--SOUTH OF AN ATLANTIC-DUBUQUE LINE AFTER 6 OR 7 PM. METEOROLOGICAL COMMENTS--MOST OF SOUTHERN IOWA REMAINS QUITE UNSTABLE WITH LIFTED INDICES AROUND -10 DEGREES AND SATELLITE MEASURED CAPES OF 3000-4000 J/KG. A DEWPOINT FRONT LYING ALONG A DUBUQUE-DES MOINES- ATLANTIC LINE MAY ACT AS A FOCUS FOR THUNDERSTORMS DEVELOPMENT THIS EVENING. THE BEST LOW LEVELING FORCING REMAINS IN NORTHEAST KANSAS HOWEVER WHERE STRONGER LOW LEVEL WINDS ARE IMPINGING THE DEWPOINT FRONT. A WEAK UPPER LEVEL DISTURBANCE IS NEARING THIS AREA FROM WESTERN KANSAS NOW...WHICH MAY INDUCE THUNDERSTORMS TO DEVELOP. PRECIPITABLE WATER VALUES ARE NEAR 2 INCHES SOUTH OF THE FRONT...SO RAINFALL WILL BE INTENSE IN LOCALIZED AREAS. THE THREAT OF STRONG DAMAGING WINDS HAS LESSENED A BIT FROM EARLIER TODAY BUT WINDS TO 70 MPH COULD OCCUR. BETWEEN SUNSET AND MIDNIGHT THE WEATHER THREAT WILL BE REPEAT HEAVY RAINS OVER THE SAME AREA. RAINFALL AMOUNTS COULD EASILY EXCEED 3-4 INCHES IN SMALL AREAS BETWEEN 10 PM AND 3 AM. PRECAUTIONS--PEOPLE WITH OUTDOOR PLANS SHOULD STAY ABREAST OF THE WEATHER THIS EVENING...AND BE PREPARED TO CHANGE PLANS. SPOTTER ACTIVATION COULD >BE NEEDED SOUTH OF AN ATLANTIC-DUBUQUE LINE. MYERS
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 16, 7:51 PM CDT | Tornado Warning | DMX | Warren | 34 min |
| Aug 16, 8:26 PM CDT | Tornado Warning | DMX | Warren | 14 min |
| Aug 16, 8:34 PM CDT | Severe Thunderstorm Warning | DMX | Monroe | 36 min |
| Aug 16, 8:51 PM CDT | Severe Thunderstorm Warning | DMX | Marion | 34 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.