Alert archive / Nebraska / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 56, NWS Cheyenne, WY

June 20, 1997Sioux County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at Jun 20, 1997, 8:59 PM MDT for Sioux County, Nebraska. 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, 8:59 PM MDT (02:59 UTC)
Expired
Jun 20, 1997, 9:30 PM MDT
In force
31 min
Issued by
NWS Cheyenne, WY
Area
Whole counties

County Sioux County, NE

The radar

The Cheyenne radar (KCYS), 172 km from the middle of the area, began a volume at 02:59 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
Jun 20, 2:30 PM MDTTornado WatchSPC7 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 3.0 hours before the alert went out and 190 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, Rapid City, SD at 00:00Z on 1997-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 63 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, Rapid City, SD at 00:00Z on 1997-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 204 square meters per square second.1939587897117Sfc1 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
63 J/kg
Mixed-layer CIN
-31 J/kg
Mixed-layer LCL
785 m above ground
0-6 km bulk shear
85 kt
0-1 km storm-relative helicity
204 m²/s²
0-3 km storm-relative helicity
211 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.

435 
WUUS1 KCYS 210300 RRA
SVRCYS
NEC165-210330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
859 PM MDT FRI JUN 20 1997

* SEVERE THUNDERSTORM WARNING FOR
  NORTHWESTERN SIOUX COUNTY IN NORTHWESTERN NEBRASKA PANHANDLE

* UNTIL 930 PM MDT

* THIS STORM IS EXPECTED TO REMAIN IN RURAL AREAS.

* AT 858 PM MDT...A SEVERE THUNDERSTORM WAS INDICATED BY DOPPLER
  RADAR 21 MILES EAST OF LUSK OR 11 MILES NORTHWEST OF HARRISON
  MOVING NORTHEAST AT 25 MPH.

THIS WARNING REPLACES THE PREVIOUSLY ISSUED WARNING FOR SOUTHEAST
NIOBRARA COUNTY. 

A TORNADO WATCH IS ALSO IN EFFECT UNTIL 900 PM.  SEVERE THUNDERSTORMS
CAN PRODUCE TORNADOES.
 
 IF YOU ARE DRIVING IN THIS AREA...YOU SHOULD BE PREPARED TO PULL OFF
THE ROAD FOR SHELTER AS THE THUNDERSTORMS APPROACH.

WEILAND

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 6:18 PM MDTSevere Thunderstorm WarningCYSCheyenne47 min
Jun 20, 6:24 PM MDTSevere Thunderstorm WarningCYSKimball46 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 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.