Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 53, NWS Des Moines, IA

June 20, 1997Butler County, Grundy County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Jun 20, 1997, 11:39 PM CDT for Butler County, Grundy 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
Jun 20, 1997, 11:39 PM CDT (04:39 UTC)
Expired
Jun 21, 1997, 12:10 AM CDT
In force
31 min
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Butler County, IA, Grundy County, IA

The radar

The Des Moines radar (KDMX), 121 km from the middle of the area, began a volume at 04:43 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

TimeReportWhereRemark
Jun 20, 11:45 PM CDTThunderstorm Wind 55Aplington, IA
Jun 21, 12:12 AM CDTThunderstorm Wind 80Dike, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jun 20, 10:00 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 4.7 hours before the alert went out and 216 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.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 1997-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4926 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 00:00Z on 1997-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
4926 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
969 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
216 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDSM 210438 RRA
SVRDSM
IAC023-075-210510-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1139 PM CDT FRI JUN 20 1997

* SEVERE THUNDERSTORM WARNING FOR
  SOUTHERN BUTLER COUNTY - NORTHEASTERN IOWA
  NORTHERN GRUNDY COUNTY - NORTHEASTERN IOWA

* UNTIL 1210 AM CDT
 
* SOME AREAS AFFECTED
    PARKERSBERG
    APLINGTON
    DIKE
    WELLSBURG

* AT 1135 PM RADAR INDICATED A SEVERE THUNDERSTORM NEAR PARKERBERG OR
  25 MILES WEST OF WATERLOO MOVING EAST AT 20 MPH.

* THE STORM WILL BE THROUGH PARKERSBERG AND NEW HARTFORD BY MIDNIGHT.

THIS IS A DANGEROUS STORM.  DO NOT GO OUTDOORS.




JOHNSON

What 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

Local storm report, Jun 20, 6:03 PM CDT, 5 hours 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
603 PM CDT FRI JUN 20 1997

TIME(CDT)   .....CITY LOCATION.....  ST   ...EVENT/REMARKS...
DATE(CDT)   ....COUNTY LOCATION....

0449 PM     INDIANOLA                IA   0.85 INCH HAIL
06/20/97    WARREN
Local storm report, Jun 20, 6:05 PM CDT, 5 hours 34 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
603 PM CDT FRI JUN 20 1997

TIME(CDT)   .....CITY LOCATION.....  ST   ...EVENT/REMARKS...
DATE(CDT)   ....COUNTY LOCATION....

0449 nPM     INDIANOLA                IA   0.85 INCH HAIL
06/20/97    WARREN
Special weather statement, Jun 20, 9:35 PM CDT, 2 hours 4 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
935 PM CDT FRI JUN 20 1997

HAZARD -- NUMEROUS THUNDERSTORMS WITH ISOLATED SEVERE THUNDERSTORMS
CAPABLE OF PRODUCING WIND GUSTS IN EXCESS OF 70 MPH...HAIL UP TO TWO
INCHES IN DIAMETER...HEAVY RAIN AND ISOLATED TORNADOES.

TIMING AND AREA OF CONCERN -- FROM 1100 PM UNTIL 300 AM OVER THE WEST
PART OF THE FORECAST AREA AND SOUTH OF U.S. HIGHWAY 20...AFTER 100 AM
EAST OF INTERSTATE 35...SOUTH OF U.S. HIGHWAY 20.  THE THREAT WILL END
OVER WESTERN IOWA BY 300 AM AND OVER THE EAST BY 600 AM.

METEOROLOGICAL COMMENTS -- A BOUNDARY LEFT FROM CONVECTION LAST NIGHT
EXTENDED FROM SOUTHERN NEBRASKA EAST THROUGH CENTRAL INTO EAST CENTRAL
IOWA.  IN ADDITION A COLD FRONT EXTENDED FROM THE NORTHEAST CORNER OF
THE STATE...SOUTHWEST INTO THE WEST CENTRAL COUNTIES NEAR ONAWA.  THE
AIRMASS OVER IOWA IS VERY UNSTABLE WITH LIFTED INDICES IN THE -10 TO
-15 DEGREE C RANGE.  IN ADDITION...CAPE VALUES WERE ON THE ORDER OF
5000 TO 6000 J/KG.  THE LATEST SURFACE ANALYSIS SHOWS DEW POINTS
TEMPERATURES OF AT LEAST 75 DEGREES OVER THE SOUTHEAST HALF OF THE
STATE.  A FEW LOCATION WERE AROUND 80.  IN ADDITION TO THE
MOISTURE...THE LOW LEVEL JET WAS INCREASING THIS EVENING.  SPEEDS WERE
IN THE 35 TO 40 MPH RANGE BY MID EVENING.  INTENSE THUNDERSTORMS WERE
FORMING IN TWO AREAS THIS EVENING.  ONE WAS OVER WESTERN
NEBRASKA...THE SECOND OVER SOUTHEAST AND EAST CENTRAL NEBRASKA.  THE
TWO AREAS ARE LIKELY TO COMBINE AND ADVANCE EAST LATER TONIGHT.  THE
GREATEST THREAT OF SEVERE WEATHER WILL BE OVER THE WEST HALF OF
IOWA...WITH THE THREAT OVER THE EAST BEING MORE FROM HEAVY RAIN.
SPOTTY RAINFALL OF 3 TO 5 INCHES ARE POSSIBLE...ESPECIALLY SOUTH OF A
SIOUX CITY TO OTTUMWA LINE.

PRECAUTIONS -- EMERGENCY MANAGERS SHOULD REMAIN ALERT AS A WATCH IS
LIKELY WITHIN THE NEXT HOUR.  SPOTTER ACTIVATION MAY BE NEEDED THIS
EVENING.  STAY TUNED TO LOCAL TV...CABLE TV OR NOAA WEATHER RADIO FOR
THE LATEST SHORT-TERM FORECAST AND SEVERE WEATHER OUTLOOK.

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 10:14 PM CDTSevere Thunderstorm WarningDMXWright31 min
Jun 20, 10:20 PM CDTSevere Thunderstorm WarningDMXWebster35 min
Jun 20, 10:30 PM CDTSevere Thunderstorm WarningDMXFranklin30 min
Jun 20, 11:01 PM CDTSevere Thunderstorm WarningDMXFranklin34 min
Jun 20, 11:33 PM CDTSevere Thunderstorm WarningDMXHardin32 min
Jun 21, 12:04 AM CDTSevere Thunderstorm WarningDMXGrundy, Hardin31 min
Jun 21, 12:21 AM CDTSevere Thunderstorm WarningDMXBlack Hawk, Grundy44 min
Jun 21, 12:28 AM CDTTornado WarningDMXBlack Hawk32 min
Jun 21, 1:41 AM CDTSevere Thunderstorm WarningDMXAudubon, Cass34 min
Jun 21, 2:39 AM CDTSevere Thunderstorm WarningDMXClarke, Warren31 min
Jun 21, 2:51 AM CDTSevere Thunderstorm WarningDMXPolk, Warren34 min
Jun 21, 3:06 AM CDTSevere Thunderstorm WarningDMXLucas, Marion29 min
Jun 21, 3:21 AM CDTSevere Thunderstorm WarningDMXMahaska, Monroe34 min
Jun 21, 3:53 AM CDTSevere Thunderstorm WarningDMXWapello32 min
Jun 21, 4:27 PM CDTTornado WarningDMXCalhoun, Webster33 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.