Alert archive / Iowa / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 89, NWS Des Moines, IA
NWS Des Moines, IA issued this severe thunderstorm warning at Jul 20, 1997, 4:50 PM CDT for Monroe County, Iowa. It was in force for 35 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 20, 1997, 4:50 PM CDT (21:50 UTC)
- Expired
- Jul 20, 1997, 5:25 PM CDT
- In force
- 35 min
- Issued by
- NWS Des Moines, IA
- Area
- Whole counties
County Monroe County, IA
The radar
The Des Moines radar (KDMX), 106 km from the middle of the area, began a volume at 21:50 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, 9.8 hours before the alert went out and 208 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
- 303 J/kg
- Mixed-layer CIN
- -205 J/kg
- Mixed-layer LCL
- 1047 m above ground
- 0-6 km bulk shear
- 7 kt
- 0-1 km storm-relative helicity
- 66 m²/s²
- 0-3 km storm-relative helicity
- 70 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 202150 RRA
SVRDSM
IAC135-202225-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
450 PM CDT SUN JUL 20 1997
* SEVERE THUNDERSTORM WARNING FOR
EASTERN MONROE COUNTY - SOUTH CENTRAL IOWA
* UNTIL 525 PM CDT
* SOME AREAS AFFECTED
BLAKESBURG
AVERY
* AT 449 PM CDT RADAR INDICATED A SEVERE THUNDERSTORM 15 MILES WEST OF
OTTUMWA NEAR BLAKESBURG MOVING NORTH AT 30 MPH.
* THE STORM WILL BE NEAR AVERY BY 500 PM .
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, Jul 20, 3:05 PM CDT, 1 hour 45 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-211200- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 306 PM CDT SUN JUL 20 1997 HAZARD--THUNDERSTORMS PRODUCING INTENSE RAINFALL. A FEW STORMS COULD PRODUCE WIND GUSTS TO 45 MPH. AREA OF CONCERN--SOUTH OF HIGHWAY 20. TIMING DETAILS--BETWEEN 3 AND 8 PM THEN OVERNIGHT. METEOROLOGICAL COMMENTS--THE OVERALL WEATHER SITUATION REMAINS UNCHANGED. COPIOUS MOISTURE IS AVAILABLE...A COLD FRONT IS NEAR NORTHWEST IOWA...GREAT INSTABILITY AND WEAK WIND FIELDS. THESE FACTORS WILL COMBINE TO PRODUCE THUNDERSTORMS WITH INTENSE RAINFALL. A CONVERGENT AREA EXISTS OVER THE CENTRAL SECTION OF THE FORECAST AREA. THUNDERSTORMS ARE FIRING UP ALONG A LINE FROM DENISON TO WATERLOO WITH MORE WIDELY SCATTERED STORMS SOUTH OF THIS LINE. THESE STORMS WILL DEVELOP AND MOVE NORTH AT 25 MILES AN HOUR THROUGH THE EVENING AND THEN AGAIN OVERNIGHT. RAINFALL RATES WILL NEAR 2 INCHES PER HOUR WITH MANY OF THESE STORMS. ISOLATED STORMS COULD PRODUCE WIND GUSTS TO 45 MPH. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND OVERNIGHT. MONITORING OF STORMS FOR FLOODING AND DAMAGE DUE TO WIND GUSTS WILL BE THE MOST LIKELY SCENARIO. FAB
Special weather statement, Jul 20, 3:06 PM CDT, 1 hour 44 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-211200- CENTRAL IOWA THUNDERSTORM OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 306 PM CDT SUN JUL 20 1997 HAZARD--THUNDERSTORMS PRODUCING INTENSE RAINFALL. A FEW STORMS COULD PRODUCE WIND GUSTS TO 45 MPH. AREA OF CONCERN--SOUTH OF HIGHWAY 20. TIMING DETAILS--BETWEEN 3 AND 8 PM THEN OVERNIGHT. METEOROLOGICAL COMMENTS--THE OVERALL WEATHER SITUATION REMAINS UNCHANGED. COPIOUS MOISTURE IS AVAILABLE...A COLD FRONT IS NEAR NORTHWEST IOWA...GREAT INSTABILITY AND WEAK WIND FIELDS. THESE FACTORS WILL COMBINE TO PRODUCE THUNDERSTORMS WITH INTENSE RAINFALL. A CONVERGENT AREA EXISTS OVER THE CENTRAL SECTION OF THE FORECAST AREA. THUNDERSTORMS ARE FIRING UP ALONG A LINE FROM DENISON TO WATERLOO WITH MORE WIDELY SCATTERED STORMS SOUTH OF THIS LINE. THESE STORMS WILL DEVELOP AND MOVE NORTH AT 25 MILES AN HOUR THROUGH THE EVENING AND THEN AGAIN OVERNIGHT. RAINFALL RATES WILL NEAR 2 INCHES PER HOUR WITH MANY OF THESE STORMS. ISOLATED STORMS COULD PRODUCE WIND GUSTS TO 45 MPH. PRECAUTIONS--SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING AND OVERNIGHT. MONITORING OF STORMS FOR FLOODING AND DAMAGE DUE TO WIND GUSTS WILL BE THE MOST LIKELY SCENARIO. FAB
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 19, 9:30 PM CDT | Flash Flood Warning | DMX | Kossuth | 3 hr |
| Jul 20, 2:59 PM CDT | Severe Thunderstorm Warning | DMX | Polk | 31 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.