Alert archive / South Dakota / Tornado Warnings in 1991

Tornado Warning 2, NWS Sioux Falls, SD

May 12, 1991Hanson County, South Dakota

NWS Sioux Falls, SD issued this tornado warning at May 12, 1991, 6:58 PM CDT for Hanson County, South Dakota. It was in force for 32 min.

The area

The counties it named.

The facts

Issued
May 12, 1991, 6:58 PM CDT (23:58 UTC)
Expired
May 12, 1991, 7:30 PM CDT
In force
32 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Hanson County, SD

The nearest sounding before it

Aberdeen, SD (KHON), launched 12:00Z, 12.0 hours before the alert went out and 145 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 12:00Z on 1991-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1568 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 12:00Z on 1991-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 square meters per square second.1939Sfc1 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
1568 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
816 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
49 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this tornado 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, May 12, 3:37 PM CDT, 3 hours 21 minutes before
SDZ016-019-122200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
335 PM CDT SUN MAY 12 1991

...TORNADO WATCH TIL 9 PM CDT FOR LARGE PART OF CENTRAL AND EASTERN
   SOUTH DAKOTA...

A TORNADO WATCH IS IN EFFECT FOR A LARGE PART OF CENTRAL AND EASTERN
SOUTH DAKOTA.

AT 330 PM A LINE OF INTENSE THUNDERSTORMS WITH VERY HEAVY RAIN AND
POSSIBLE HAIL WAS DEVELOPING FROM 40 MILES NORTH OF WINNER TO 20 MILES
EAST OF WINNER. THE STRONGEST OF THESE STORMS WAS 20 MILES EAST OF
WINNER NEAR LAKE BURCH. THE STORMS WERE MOVING TO THE NORTH NORTHEAST
AT 30 MPH.

PEOPLE IN EASTERN STANLEY...WESTERN BRULE...GREGORY AND NORTHWEST
CHARLES MIX COUNTY SHOULD REMAIN ALERT TO THE POSSIBILITY OF SEVERE
WEATHER.

BIER

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 3:59 PM CDTSevere Thunderstorm WarningFSDBrule46 min
May 12, 4:51 PM CDTSevere Thunderstorm WarningFSDBrule39 min
May 12, 5:41 PM CDTSevere Thunderstorm WarningFSDDouglas34 min
May 12, 6:56 PM CDTTornado WarningFSDHanson34 min

Nearby

Tornado Warnings in South Dakota, 1991Every tornado warning in 1991Tornadoes in 1991

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.