Alert archive / Wyoming / Tornado Warnings in 1987

Tornado Warning 12, NWS Cheyenne, WY

June 20, 1987Laramie County, Wyoming

NWS Cheyenne, WY issued this tornado warning at Jun 20, 1987, 2:39 PM MDT for Laramie County, Wyoming. It was in force for 36 min.

The area

The counties it named.

The facts

Issued
Jun 20, 1987, 2:39 PM MDT (20:39 UTC)
Expired
Jun 20, 1987, 3:15 PM MDT
In force
36 min
Issued by
NWS Cheyenne, WY
Area
Whole counties

County Laramie County, WY

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 8.7 hours before the alert went out and 202 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, Denver, CO at 12:00Z on 1987-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 791 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 1987-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
791 J/kg
Mixed-layer CIN
-190 J/kg
Mixed-layer LCL
1292 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCYS 202040
TORCYS
WYC021-202145-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
239 PM MDT SAT JUN 20 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING
EFFECTIVE UNTIL 345 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST WYOMING...SOUTHEAST LARAMIE COUNTY

THIS INCLUDES THE CITIES OF CARPERNTER...EGBERT...PINE BLUFFS AND
BURNS.

AT 235 PM A TORNADO WAS REPORTED ON THE GROUND 2 MILES EAST OF
CARPENTER MOVING EAST.

IF YOU ARE IN THE PATH OF THIS TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH OR PIECE OF STURDY FURNITURE. IF
NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM ON THE
LOWEST FLOOR.  USE BLANKETS OR PILLOWS TO COVER YOUR BODY.

DASELER

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, Jun 20, 1:53 PM MDT, 46 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
150 PM MDT SAT JUN 20 1987

SOME STRONG THUNDERSTORMS HAVE DEVELOPED IN THE CHEYENNE VICINITY
SINCE NOONTIME.

RADAR INDICATED A BAND OF THUNDERSTORMS JUST SOUTH OF THE CITY ALONG
THE COLORADO BORDER.  ANOTHER AREA OF STORMS WAS DEVELOPING JUST A
FEW MILES NORTHEAST OF CHEYENNE AT 145 PM...ALL MOVING EAST.

NO SEVERE WEATHER HAS BEEN REPORTED FROM THESE STORMS.  WITH DRY AIR
NEAR THE SURFACE...A LOT OF THE RAIN WAS EVAPORATING BEFORE IT REACHED
THE GROUND.  THIS HAS RESULTED IN RATHER OMINOUS LOOKING RAIN SHAFTS
THAT HAVE A FUNNEL SHAPE.

A FEW OF THE STORMS BY LATER THIS AFTERNOON COULD PRODUCE GUSTY WINDS
AND POSSIcBLY SOME SMALL HAIL.  IF A THREATENING THUNDERSTORM MOVES
INTO YOUR AREA...GO TO A SAFE PLACE AND THEN REPORT ANY SIGNIFICANT
WEATHER TO THE NATIONAL WEATHER SERVICE OR LAW ENFORCEMENT AGENCIES.

DASELER

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 6:15 PM MDTTornado WarningCYSCrook45 min
Jun 19, 7:28 PM MDTSevere Thunderstorm WarningCYSLaramie, Platte62 min

Nearby

Tornado Warnings in Wyoming, 1987Every tornado warning in 1987Tornadoes in 1987

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.