Alert archive / Wyoming / Flash Flood Warnings in 1987

Flash Flood Warning 1, NWS Cheyenne, WY

June 7, 1987Platte County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at Jun 7, 1987, 9:03 PM MDT for Platte County, Wyoming. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jun 7, 1987, 9:03 PM MDT (03:03 UTC)
Expired
Jun 8, 1987, 12:00 AM MDT
In force
3 hr
Issued by
NWS Cheyenne, WY
Area
Whole counties

County Platte 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

Rapid City, SD (KRAP), launched 00:00Z, 3.1 hours before the alert went out and 274 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 1987-06-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 651 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 1987-06-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 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
651 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
1311 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCYS 080303
FFWCYS
WYC031-080600-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
903 PM MDT SUN JUN 7 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING 
EFFECTIVE UNTIL 1200 AM MDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

SOUTHEAST WYOMING...CENTRAL SOUTH PLATTE COUNTY

THIS WARNING INCLUDES THE CITIES OF WHEATLAND...CHUGWATER...AND
SLATER WYOMING. AT 850 PM FLASH FLOODING WAS REPORTED IN WHEATLAND
WYOMING. WHEATLAND IS 54 MILES NORTH OF CHEYENNE WYOMING.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS THE
ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...
ON FOOT.  MOVE TO HIGHER GROUND.

RIZZO

What forecasters said that day

The local office's own words before this flash flood 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 7, 3:11 PM MDT, 5 hours 52 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
300 PM MDT SUN JUN 7 1987

...STRONG THUNDERSTORMS CONTINUE IN SOUTH ALBANY COUNTY WYOMING...

AT 300 PM MDT...A VERY STRONG THUNDERSTORM WAS OVER SOUTH ALBANY COUNTY
WYOMING...20 MILES WEST OF LARAMIE. THIS STORM PRODUCED VERY HEAVY RAIN
IN ALBANY WYOMING AROUND 230 PM. AT 250 PM...THE ALBANY COUNTY SHERIFF
REPORTED PEA SIZE HAIL COVERING HIGHWAY 11 JUST NORTHWEST OF ALBANY.
THE STORM WAS MOVING NORTHEAST AT 15 TO 20 MILES AN HOUR. IT WILL
LIKELY PASS JUST NORTHWEST OF LARAMIE THE DURING THE NEXT HOUR.

ANOTHER STRONG THUNDERSTORM WAS IN NORTH ALBANY COUNTY...45 MILES
SOUTHEAST OF CASPER.

THUNDERSTORMS WILL CONTINUE OVER SOUTHEAST WYOMING INTO THE EVENING
HOURS...DISSIPATING AROUND SUNSET. BRIEF HEAVY RAIN...GUSTY WIND AND
SMALL HAIL CAN BE EXPECTED WITH THESE STORMS.
JPK
Special weather statement, Jun 7, 6:14 PM MDT, 2 hours 49 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
612 PM MDT SUN JUN 7 1987

...SEVERE THUNDERSTORM WARNING FOR NORTHWEST ALBANY AND CENTRAL PLATTE
   COUNTIES UNTIL 630 PM...

AT 547 PM A SEVERE THUNDERSTORM WAS LOCATED OVER THE RIDGE OF THE
LARAMIE RANGE...25 MILES EAST OF GARRETT OR 40 MILES SOUTHEAST OF
DOUGLAS.

THIS SEVERE THUNDERSTORM WAS STATIONARY...CREATING THE POTENTIAL
FOR FLASH FLOODING.  RADAR INDICATED THAT THIS THUNDERSTORM ALSO HAS
THE POTENTIAL TO PRODUCE LARGE DAMAGING HAIL.

RAIN FROM THIS SEVERE THUNDERSTORM WILL FEED INTO THE NORTH LARAMIE
RIVER BASIN.  PERSONS IN THE TOWN OF UVA...59 MILES NORTH OF CHEYENNE
...SHOULD BE ON THE WATCH FOR POSSIBLE FLASH FLOODING.

LARGE HAIL...VERY HEAVY RAIN AND DAMAGING HAIL ARE POSSIBLE WITH SEVERE
THUNDERSTORMS.

IF FLASH FLOODING IS OBSERVED...ACT QUICKLY.  MOVE TO ESCAPE THE
FLOOD WATERS.  DO NOT STAY IN AREAS PRONE TO FLOODING IF WATERS
START TO RAISE.
W
IF YOU EXPERIENCE SEVERE WEATHER...REPORT IT TO THE NATIONAL
WEATHER SERVICE OR TO THE NEAREST LAW ENFORCEMENT AGENCY AS SOON AS
POSSIBLE.
ML

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 7, 6:30 PM MDTSevere Thunderstorm WarningCYSAlbany, Platte60 min
Jun 7, 7:25 PM MDTSevere Thunderstorm WarningCYSPlatte65 min
Jun 7, 7:35 PM MDTTornado WarningCYSPlatte55 min
Jun 7, 8:30 PM MDTSevere Thunderstorm WarningCYSLaramie, Platte60 min
Jun 7, 9:33 PM MDTSevere Thunderstorm WarningCYSLaramie57 min
Jun 7, 10:04 PM MDTTornado WarningCYSGoshen56 min

Nearby

Flash Flood Warnings in Wyoming, 1987Every flash flood warning 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.