Alert archive / South Dakota / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 112, NWS Sioux Falls, SD

August 2, 1997Sanborn County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Aug 2, 1997, 8:37 PM CDT for Sanborn County, South Dakota. It was in force for 33 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
Aug 2, 1997, 8:37 PM CDT (01:37 UTC)
Expired
Aug 2, 1997, 9:10 PM CDT
In force
33 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Sanborn County, SD

The radar

The Sioux Falls radar (KFSD), 120 km from the middle of the area, began a volume at 01:40 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 watch it was issued in

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

IssuedProductOfficeLasted
Aug 2, 4:00 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Aberdeen, SD (KABR), launched 00:00Z, 1.6 hours before the alert went out and 101 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, Aberdeen, SD at 00:00Z on 1997-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 290 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, Aberdeen, SD at 00:00Z on 1997-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 square meters per square second.19395878Sfc1 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
290 J/kg
Mixed-layer CIN
-177 J/kg
Mixed-layer LCL
1669 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
292 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 030138 RRA
SVRFSD
SDC111-030210-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
837 PM CDT SAT AUG 2 1997

* SEVERE THUNDERSTORM WARNING FOR
  NORTHERN SANBORN COUNTY IN EASTCENTRAL SOUTH DAKOTA

* UNTIL 910 PM CDT
 
* THIS STORM IS EXPECTED TO REMAIN IN RURAL AREAS.

* AT 836 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORM 7 MILES SOUTHEAST OF HURON  MOVING SOUTHEAST
  AT 30 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 DR`IVE INTO LOW WATER CROSSINGS.

UMLAND

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 Aug 1, 8:56 PM CDT, 23 hours 41 minutes earlier.

Area forecast discussion, Aug 1, 8:56 PM CDT, 23 hours 41 minutes before
SOUTH DAKOTA/NORTHWEST IOWA/SOUTHWEST MINNESOTA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
855 PM CDT FRI AUG 1 1997

SHORT WAVE TROUGH WELL EVIDENT IN WV IMAGERY AND IN EVNG RAOBS
ACRS WRN ND...LTL STGR THAN MRNG MDLS INDICATE.  ANY TSRA THAT
WOULD SURVIVE NIGHTFALL SHOULD NOT AFFECT CWA.  MAIN ISSUE TNGT
BECOMES TMPS AND FOG POTENTIAL.  AT SFC...WK CONVERGENCE BOUNDARY
HELPING TO POOL LOW LVL MSTR ACRS FSD CWA.  FLUSH OF LLM THRU MN
IS MUCH WKR THAN 21Z RUC WOULD INDICATE...AND SUBSIDENCE FAVORING
PROFILE STARTING TO WKN IN WDL PROFILER.  FLOW ALREADY RETURNING
TOWARD SRLY W.  PATHETIC SFC GRADIENT MEANS ONLY SIG DRYING TNGT
WOULD HAVE TO ORIGINATE FM ALOFT...AND MOST SHALLOW MOIST LYR OVR
BIS-MPX.  THIS MAY BE WKLY INDICATED BY MML DEWPOINT TREND.  THUS
COOLEST TMPS IN AREA SHOULD BE BTTR MIXED FAR W AND ALSO BKX-MML.
ANY DEVIATION FM CRNT FCST SHUD BE A HALF CAT OR LESS...HIER SE AND
LWR NE...SO WL HANDLE IN SHORT JTERM FCST.  WL ALSO PUT IN MNTN OF
FOG...ESPLY MO RVR AREAS AND NW IA IN AREAS OF ERLY MRNG RAINS.

.FSD...NONE
CHAPMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 2, 8:11 PM CDTSevere Thunderstorm WarningFSDBeadle49 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 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.