Alert archive / Wyoming / Tornado Warnings in 1987

Tornado Warning 19, NWS Cheyenne, WY

August 9, 1987Laramie County, Wyoming

NWS Cheyenne, WY issued this tornado warning at Aug 9, 1987, 6:48 PM MDT for Laramie County, Wyoming. It was in force for 57 min.

The area

The counties it named.

The facts

Issued
Aug 9, 1987, 6:48 PM MDT (00:48 UTC)
Expired
Aug 9, 1987, 7:45 PM MDT
In force
57 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 00:00Z, 0.8 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 00:00Z on 1987-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Denver, CO at 00:00Z on 1987-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -72 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2293 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
-72 m²/s²
0-3 km storm-relative helicity
-153 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 100048
TORCYS
WYC021-100145-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
648 PM MDT SUN AUG 9 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 745 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST WYOMING...NORTHWEST LARAMIE COUNTY

AT 645PM CHEYENNE RADAR INDICATED A POSSIBLE TORNADO WITH THE
SEVERE THUNDERSTORM LOCATED 6 MILES WEST OkF HORSE CREEK.  THIS WAS
32 MILES NORTHWEST OF CHEYENNE.

THIS TORNADO WARNING INCLUDES THE TOWN OF HORSE CREEK BUT NOT THE
CITY OF CHEYENNE.

COX

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, Aug 9, 4:34 PM MDT, 2 hours 14 minutes before
RADAR SUMMARY
NATIONAL WEATHER SERVICE CHEYENNE WY
430 PM MDT SUN AUG 9 1987

...STRONG THUNDERSTORMS WERE OVER SOUTHEAST WYOMING...

SEVERAL STRONG THUNDERSTORMS CONTINUED TO MOVE SLOWLY ACROSS SOUTHEAST
WYOMING. ONE STORM WAS 5 MILES EAST OF LA GRANGE...50 MILES NORTHEAST OF
CHEYENNE WHILE ANOTHER WAS OVER THE LARAMIE RANGE 40 MILES NORTHWEST
OF CHEYENNE.

THESE STORMS WILL LIKELY PRODUCE HEAVY RAIN...STRONG GUSTY WINDS AND
SMALL HAIL. THEY WERE MOVING NORTHEAST ABOUT 10 MILES AN HOUR. WITH
THIS SLOW MOVEMENT...SOME FLOODING OF SMALL STREAMS...ROADS AND LOW
LYING AREAS WILL BE POSSIBLE.

ANOTHER STORNG THUNDERSTORM WAS IN NORTH COLORADO...20 MILES SOUTH OF
CHEYENNE. IT WAS ALSO MOVING NORTHEAST AT 10 MILES AN HOUR...SO IT MAY
MOVE ACROSS THE EXTREME SOUTHEAST CORNER OF WYOMING. PEOPLE IN CARPENTER
AND PINE BLUFFS SHOULD BE AWARE OF POSSIBLE HEAVY RAIN..GUSTY WINDS AND
HAIL FOR THE NEXT COUPLE OF HOURS.
JPK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 6:02 PM MDTSevere Thunderstorm WarningCYSLaramie58 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.