Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 15, NWS Sioux Falls, SD

June 20, 1997Buena Vista County, Cherokee County, Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jun 20, 1997, 3:34 AM CDT for Buena Vista County, Cherokee County, Iowa. It was in force for 31 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
Jun 20, 1997, 3:34 AM CDT (08:34 UTC)
Expired
Jun 20, 1997, 4:05 AM CDT
In force
31 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Buena Vista County, IA, Cherokee County, IA

The radar

The Sioux Falls radar (KFSD), 144 km from the middle of the area, began a volume at 08:38 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

Omaha, NE (KOAX), launched 00:00Z, 8.6 hours before the alert went out and 177 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, Omaha, NE at 00:00Z on 1997-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1320 joules per kilogram.LCLEL10008507005003002001001 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, Omaha, NE at 00:00Z on 1997-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
1320 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
2762 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

877 
WUUS1 KFSD 200835 RRA
SVRFSD
IAC021-200905-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
334 AM CDT FRI JUN 20 1997

* SEVERE THUNDERSTORM WARNING FOR
  CHEROKEE COUNTY - IN NORTHWESTERN IOWA

* UNTIL 405 AM CDT
 
* SOME AREAS AFFECTED
  HANOVER                  
  CHEROKEE                
  QUINBY        
  WASHTA                    

* AT 330 AM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 41
MILES NORTHEAST OF SIOUX CITY OR 16 MILES  NORTHWEST OF HANOVER
MOVING EAST AT 35 MPH.
 
WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DO NOT USE TELEPHONES OR
ELECTRICAL APPLIANCES UNTIL THE STORM HAS PASSED UNLESS IN AN
EMERGENCY.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

RUBY
1 follow-up statement
885 
WUUS1 KFSD 200836 RRB
SVRFSD
IAC035-200905-

BULLETIN - IMMEDIATE BROADCAST REQUESTED...CORRECTION FOR CODING
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
334 AM CDT FRI JUN 20 1997

* SEVERE THUNDERSTORM WARNING FOR
  CHEROKEE COUNTY - IN NORTHWESTERN IOWA

* UNTIL 405 AM CDT

* SOME AREAS AFFECTED
  HANOVER
  CHEROKEE
  QUINBY
  WASHTA

* AT 330 AM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 41
MILES NORTHEAST OF SIOUX CITY OR 16 MILES  NORTHWEST OF HANOVER
MOVING EAST AT 35 MPH.

WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DO NOT USE TELEPHONES OR
ELECTRICAL APPLIANCES UNTIL THE STORM HAS PASSED UNLESS IN AN
EMERGENCY.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

RUBY

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.

NWS Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 19, 8:29 PM CDT, 7 hours 5 minutes earlier.

Area forecast discussion, Jun 19, 8:29 PM CDT, 7 hours 5 minutes before
SOUTH DAKOTA/NORTHWEST IOWA/SOUTHWEST MINNESOTA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
830 PM CDT WED JUN 18 1997

SEVERE THUNDERSTORM POTENTIAL HAS NOT DEVELOPED AS WELL AS EARLIER
EXPECTED AND SOME ADJUSTMENT TO EARLIER CWA ZONES WILL BE MADE.  WILL
ADJUST ZONES IN LINE WITH SPC CHANGES TO WATCH AREA WHICH IS ANTICIPATED
AROUND 9 PM.  WILL LOWER THE POPS FOR LATER TONIGHT FOLLOWING THE
THUNDERSTORMS MOVING ALONG THE SOUTHEAST BORDER. POTENTIAL FOR SEVERE
THUNDERSTORMS YET THROUGH MIDNIGHT FROM AROUND YANKTON ON EAST INTO
NORTHWEST IOWA AS THE THUNDERSTORMS MOVE INTO THAT AREA.

.FSD...NONE
UMLAND

In the hours before

Local storm report, Jun 19, 10:55 PM CDT, 4 hours 39 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE  SIOUX FALLS SD
1055 PM CDT THU JUN 19 1997

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0910 PM    CLAYTON                   SD   1.25 INCH HAIL
06/19/97   HUTCHINSON                     4 MILES SOUTH OF CLAYTON

UMLAND
Special weather statement, Jun 19, 11:04 PM CDT, 4 hours 30 minutes before
NEZ013-014-SDZ060>062-065>071-200510-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1104 PM CDT THU JUN 19 1997

THE SEVERE THUNDERSTORM WATCH NUMBER 482 WHICH WAS IN EFFECT FOR
EXTREME SOUTHEAST SOUTH DAKOTA AND DAKOTA AND DIXON COUNTIES OF
EXTREME NORTHEAST NEBRASKA HAS BEEN CANCELED.  THUNDERSTORMS HAVE
MOVED OUT OF THE AREA.

ADDITIONAL THUNDERSTORMS MAY DEVELOP LATER TONIGHT.

UMLAND
Special weather statement, Jun 20, 1:45 AM CDT, 1 hour 49 minutes before
IAZ001>003-012>014-020>022-031-032-MNZ089-090-098-200800-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
145 AM CDT FRI JUN 20 1997

...SEVERE THUNDERSTORM WATCH HAS BEEN ALLOWED TO EXPIRE...

SEVERE THUNDERSTORM WATCH NUMBER 482 FOR PARTS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA HAS BEEN ALLOWED TO EXPIRE. SCATTERED
THUNDERSTORMS WILL MOVE ACROSS EAST ACROSS THE AREA THE REST OF
TONIGHT...BUT THE STORMS ARE NOT EXPECTED TO BECOME SEVERE. HOWEVER
A FEW OF THE STORMS WILL BE STRONG ENOUGH TO PRODUCE HEAVY
RAIN...SMALL HAIL...AND GUSTY WINDS.

RUBY
Special weather statement, Jun 20, 1:45 AM CDT, 1 hour 49 minutes before
IAZ001>003-012>014-020>022-031-032-MNZ089-090-098-200800-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
145 AM CDT FRI JUN 20 1997

...CORRECTED FOR EXTRA WORDING IN LINE 3...

...SEVERE THUNDERSTORM WATCH HAS BEEN ALLOWED TO EXPIRE...

SEVERE THUNDERSTORM WATCH NUMBER 482 FOR PARTS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA HAS BEEN ALLOWED TO EXPIRE. SCATTERED
THUNDERSTORMS WILL MOVE EAST ACROSS THE AREA FOR THE REST OF
TONIGHT...BUT THE STORMS ARE NOT EXPECTED TO BECOME SEVERE. HOWEVER
A FEW OF THE STORMS WILL BE STRONG ENOUGH TO PRODUCE HEAVY
RAIN...SMALL HAIL...AND GUSTY WINDS.

RUBY
Special weather statement, Jun 20, 1:51 AM CDT, 1 hour 43 minutes before
IAZ001>003-012>014-020>022-031-032-MNZ089-090-098-200800-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
145 AM CDT FRI JUN 20 1997

...CORRECTED FOR EXTRA WORDING IN LINE 3...

...SEVERE THUNDERSTORM WATCH HAS BEEN ALLOWED TO EXPIRE...

SEVERE THUNDERSTORM WATCH NUMBER 482 FOR PARTS OF SOUTHWEST
MINNESOTA AND NORTHWEST IOWA HAS BEEN ALLOWED TO EXPIRE. SCATTERED
THUNDERSTORMS WILL MOVE EAST ACROSS THE AREA FOR THE REST OF
,TONIGHT...BUT THE STORMS ARE NOT EXPECTED TO BECOME SEVERE. HOWEVER
A FEW OF THE STORMS WILL BE STRONG ENOUGH TO PRODUCE HEAVY
RAIN...SMALL HAIL...AND GUSTY WINDS.

RUBY

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 2:51 AM CDTSevere Thunderstorm WarningFSDPlymouth29 min
Jun 20, 5:54 AM CDTSevere Thunderstorm WarningFSDLyon, Sioux31 min
Jun 20, 6:29 AM CDTSevere Thunderstorm WarningFSDSioux36 min
Jun 20, 8:28 AM CDTSevere Thunderstorm WarningFSDO'Brien, Osceola32 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.