Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 87, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Jul 19, 1997, 6:38 PM CDT for Mahaska County, Marion County, Iowa. It was in force for 32 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
- Jul 19, 1997, 6:38 PM CDT (23:38 UTC)
- Expired
- Jul 19, 1997, 7:10 PM CDT
- In force
- 32 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
Counties Mahaska County, IA, Marion County, IA
The radar
The Des Moines radar (KDMX), 84 km from the middle of the area, began a volume at 23:37 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, 11.6 hours before the alert went out and 200 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
- 232 J/kg
- Mixed-layer CIN
- -190 J/kg
- Mixed-layer LCL
- 1181 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 116 m²/s²
- 0-3 km storm-relative helicity
- 158 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDSM 192338 RRA
SVRDSM
IAC123-125-200010-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
638 PM CDT SAT JUL 19 1997
* SEVERE THUNDERSTORM WARNING FOR
SOUTHWESTERN MAHASKA COUNTY - SOUTHEASTERN IOWA
SOUTHEASTERN MARION COUNTY - SOUTH CENTRAL IOWA
* UNTIL 710 PM CDT
* SOME AREAS AFFECTED
BUSSEY
MARYSVILLE
OPEN FARMLAND ALONG HIGHWAY G71
* AT 635 PM CDT RADAR INDICATED A SEVERE THUNDER8STORM 10 MILES
SOUTHWEST OF OSKALOOSA OR ABOUT 50 MILES SOUTHEAST OF DES MOINES
MOVING SOUTH AT 5 MPH.
* THE STORM WILL BE MAINLY OVER OPEN FARMLAND.
THIS IS A DANGEROUS STORM. DO NOT GO OUTDOORS.
SMITHWhat 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, Jul 19, 5:08 PM CDT, 1 hour 30 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-200410- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 508 PM CDT SAT JUL 19 1997 HAZARD--WIDELY SCATTERED THUNDERSTORMS THIS EVENING CAPABLE OF PRODUCING TORRENTIAL RAINFALL OF FROM 2 TO 3 INCHES IN AN HOURS TIME ALONG WITH THE POTENTIAL FOR HAIL. ADDITIONAL THUNDERSTORM DEVELOPMENT EXPECTED LATER TONIGHT. AREA OF CONCERN--FAR EASTERN PORTION OF THE WARNING AREA...ALONG AND EAST OF AN OTTUMWA TO WATERLOO LINE. LATE TONIGHT THE THREAT WILL SHIFT INTO THE NORTHERN QUARTER OF THE STATE...NORTH OF HIGHWAY 20. TIMING DETAILS--THROUGH 700 PM OVER THE FAR EASTERN WARNING AREA WITH ADDITIONAL THUNDERSTORMS PUSHING INTO NORTHERN IOWA AFTER MIDNIGHT. METEOROLOGICAL COMMENTS--A RATHER DISTINCT FRONTAL BOUNDARY WAS LOCATED OVER NORTH CENTRAL THROUGH EASTERN IOWA THIS EVENING. TEMPERATURES TO THE EAST OF THE BOUNDARY WERE IN THE MID 60S WHILE READINGS WEST OF THE FRONT WERE IN THE 90S. THIS TEMPERATURE DISCONTINUITY IS HELPING FUEL WIDELY SCATTERED THUNDERSTORMS ACROSS THE FAR EASTERN WARNING AREA WITH THE PRIMARY THREAT FROM THESE STORMS BEING VERY HEAVY RAINFALL AND LARGE HAIL. LATER THIS EVENING AS THE THERMAL BOUNDARY WEAKENS...THE THUNDERSTORM THREAT WILL GRADUALLY DIMINISH. LATER TONIGHT...A NEW THUNDERSTORM COMPLEX IS FORECAST TO DEVELOP ACROSS THE DAKOTAS AND MINNESOTA WITH MOVEMENT INTO EXTREME NORTHERN IOWA AFTER MIDNIGHT. SOUTHERLY WINDS AT THE LOW LEVELS ARE FORECAST TO INCREASE AFTER DARK TRANSPORTING COPIOUS AMOUNTS OF MOISTURE NORTHWARD INTO THE STATE. WITH THE FRONTAL BOUNDARY FORECAST TO BE ACROSS NORTHERN AND EASTERN IOWA OVERNIGHT...THE PRIMARY AREA OF CONCERN WOULD BE NORTH OF HIGHWAY 20. PRECIPITABLE WATER VALUES ARE WELL ABOVE NORMAL FOR THIS TIME OF YEAR INDICATING A REAL THREAT FOR SIGNIFICANT RAINFALL IN AREAS THAT DO SEE THE THUNDERSTORMS LATER TONIGHT. PRECAUTIONS--SPOTTER ACTIVATION APPEARS UNLIKELY THIS EVENING. KEEP ABREAST OF LATER SHORT TERM FORECASTS AND CENTRAL IOWA THUNDERSTORM OUTLOOKS THIS EVENING. SMITH
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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.