Alert archive / South Dakota / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 77, NWS Sioux Falls, SD

July 20, 1997Beadle County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Jul 20, 1997, 3:26 AM CDT for Beadle County, South Dakota. It was in force for 34 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, 3:26 AM CDT (08:26 UTC)
Expired
Jul 20, 1997, 4:00 AM CDT
In force
34 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

County Beadle County, SD

The radar

The Aberdeen radar (KABR), 116 km from the middle of the area, began a volume at 08:26 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

Aberdeen, SD (KABR), launched 00:00Z, 8.4 hours before the alert went out and 55 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 1997-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2323 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 1997-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
2323 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
1325 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
84 m²/s²
Significant tornado parameter
0.4
Supercell composite
3.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 200826 RRA
SVRFSD
SDC005-200900-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
326 AM CDT SUN JUL 20 1997

* SEVERE THUNDERSTORM WARNING FOR
  EASTERN BEADLE COUNTY IN EASTCENTRAL SOUTH DAKOTA

* UNTIL 400 AM CDT
 
* SOME AREAS AFFECTED
HURON                    AROUND 330 AM CDT
CAVOUR                   AROUND 345 AM CDT

* AT 323 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORM IN THE VICINITY OF HURON  MOVING NORTHEAST
AT   15 MPH.
 
WILLIAMS

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 Jul 19, 9:07 PM CDT, 6 hours 19 minutes earlier.

Area forecast discussion, Jul 19, 9:07 PM CDT, 6 hours 19 minutes before
SOUTH DAKOTA/NORTHWEST IOWA/SOUTHWEST MINNESOTA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
900 PM CDT SAT JUL 19 1997

NOT MUCH TIME FOR DISCUSSION. SLOW MOVING TSTSM DVLPD ALONG SFC BNDRY
JUST S OF FSD ALONG AND EAST TO WEST LINE IN FAR NWRN IA. UPDATED ZONES
FOR EXPIRATION OF BEADLE COUNTY WATCH AND NEW WATCH FOR SRN CWA UNTIL
1 AM CDT. 88-D SHOWS THUNDERSTORMS TO BE VERTICALLY STACKED WITH LITTLE
WIND SHEAR SO BELIEVE MAIN THREAT TO BE FLASH FLOODING WITH LOCAL AMOUNTS
OF THREE INCHES PLUS OUT OF SOME OF THESE CELLS. WILL ISSUE A FLASH FLOOD
WATCH FOR NORTHERN THREE TIERS OF COUNTIES IN NW IA WHEN TIME ALLOWS.

.FSD...SEVERE THUNDERSTORM WATCH UNTIL 1 AM FOR SOUTHEAST SOUTH DAKOTA...
FAR SOUTHWEST MINNESOTA...NORTHWEST IOWA AND FAR NORTHEAST NEBRASKA.

FUHS

In the hours before

Special weather statement, Jul 19, 10:33 PM CDT, 4 hours 53 minutes before
NEZ013-014-SDZ060>062-065>071-200435-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1033 PM CDT SAT JUL 19 1997

THE SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED FOR SOUTHEAST
SOUTH DAKOTA AND EXTREME NORTHEAST NEBRASKA.  A SEVERE THUNDERSTORM
WATCH REMAINS IN EFFECT FOR SOUTHWEST MINNESOTA AND NORTHWEST IOWA
UNTIL 100 AM CDT.

AT 1030 PM SIOUX FALLS DOPPLER RADAR SHOWED THUNDERSTORMS WITH
HEAVY RAIN IN AN EAST TO WEST LINE ACROSS SOUTHERN SOUTH DAKOTA
INTO NORTHWEST IOWA.  THESE STORMS WERE NEARLY STATIONARY AND
DRFITING SLOWLY TO THE EAST.

SEVERE WEATHER IS NOT ANTICIPATED WITH THESE STORMS BUT HEAVY
RAINFALL IS LIKELY.  RAINFALL RATES MAY APPROACH ONE TO TWO INCHES
PER HOUR IN A FEW LOCALLIZED AREAS WITH SOME OF THESE STORMS.

PAY ATTENTIONA AT NIGHT WHEN IT IS HARDER TO SEE FLOODED ROADWAYS.
STAY TUNDE TO NOAA WEATHER RADIO AND THE LOCAL MEDI FOR FURTHER
UPDATES.

HOLMES
Special weather statement, Jul 19, 10:34 PM CDT, 4 hours 52 minutes before
NEZ013-014-SDZ060>062-065>071-200435-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1033 PM CDT SAT JUL 19 1997

THE SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED FOR SOUTHEAST
SOUTH DAKOTA AND EXTREME NORTHEAST NEBRASKA.  A SEVERE THUNDERSTORM
WATCH REMAINS IN EFFECT FOR SOUTHWEST MINNESOTA AND NORTHWEST IOWA
UNTIL 100 AM CDT.

AT 1030 PM SIOUX FALLS DOPPLER RADAR SHOWED THUNDERSTORMS WITH
HEAVY RAIN IN AN EAST TO WEST LINE ACROSS SOUTHERN SOUTH DAKOTA
INTO NORTHWEST IOWA.  THESE STORMS WERE NEARLY STATIONARY AND
DRFITING SLOWLY TO THE EAST.

SEVERE WEATHER IS NOT ANTICIPATED WITH THESE STORMS BUT HEAVY
RAINFALL IS LIKELY.  RAINFALL RATES MAY APPROACH ONE TO TWO INCHE6S
PER HOUR IN A FEW LOCALLIZED AREAS WITH SOME OF THESE STORMS.

PAY ATTENTIONA AT NIGHT WHEN IT IS HARDER TO SEE FLOODED ROADWAYS.
STAY TUNDE TO NOAA WEATHER RADIO AND THE LOCAL MEDI FOR FURTHER
UPDATES.

HOLMES
Special weather statement, Jul 20, 12:58 AM CDT, 2 hours 28 minutes before
IAZ001>003-012>014-020>022-031-032-MNZ089-090-098-200650-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1258 AM CDT SUN JUL 20 1997

THE SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTHWEST MINNESOTA
AND NORTHWEST IOWA HAS EXPIRED.  CONDITIONS FAVORABLE FOR SEVERE
THUNDERSTORMS HAVE WEAKENED.

AT 1245 AM SIOUX FALLS DOPPLER RADAR CONTINUED TO SHOW
THUNDERSTORMS DEVELOPING OVER NORTHWEST IOWA AND FAR SOUTHWEST
MINNESOTA BUT THEY WERE NOT PRODUCING SEVERE WEATHER.  HOWEVER VERY
HEAVY RAIN WAS FALLING WITH THESE STORMS AND RADAR ESTIMATES OF
RAINFALL HAVE BEEN IN THE ONE TO TWO INCH PER HOUR RANGE.

IF YOU ARE TRAVELING ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA
TONIGHT BE ON THE LOOK OUT FOR FLOODED ROADWAYS.  DO NOT CROSS
FLOODED ROADS.

HOLMES

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.