Alert archive / Wyoming / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 97, NWS Cheyenne, WY

August 11, 1990Platte County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 11, 1990, 2:17 PM MDT for Platte County, Wyoming. It was in force for 28 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 11, 1990, 2:17 PM MDT (20:17 UTC)
Expired
Aug 11, 1990, 2:45 PM MDT
In force
28 min
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.

What was reported inside it

TimeReportWhereRemark
Aug 11, 2:25 PM MDTHail 2Platte, WY

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 8.3 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 12:00Z on 1990-08-11Temperature 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, Rapid City, SD at 12:00Z on 1990-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
974 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
109 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 112018
SVRCYS
WYC031-112045-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
217 PM MDT SAT AUG 11 1990
 
THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  245 PM MDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST WYOMING
          ...SOUTHERN PLATTE INCLUDING THE TOWN OF CHUGWATER
 
RADAR INDICATED A SEVERE THUNDERSTORM ABOUT 25 MILES SOUTH OF
WHEATLAND MOVING EAST AT 25 MILES AN HOUR.
 
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS.
STAY INGSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

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.

In the hours before

Special weather statement, Aug 11, 12:36 PM MDT, 1 hour 41 minutes before
WYZ012-017-112000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
1238 PM MDT SAT AUG 11 1990

...STRONG THUNDERSTORMS NORTHWEST OF WHEATLAND...

AT 1230 PM RADAR INDICATED STRONG THUNDERSTORMS OVER THE LARAMIE
RANGE OF SOUTHEAST WYOMING.  THE THUNDERSTORMS WERE ABOUT 25 MILES
NORTHWEST OF WHEATLAND AND MOVING TO THE EAST AT ABOUT 25 MILES AN
HOUR.

HAIL...HEAVY RAIN AND GUSTY WINDS WERE LIKELY WITH THESE STORMS.
PEOPLE IN NORTHERN PLATTE COUNTY ESPECIALLY PEOPLE ON THE WATER
SHOULD BE ALERT FOR FAST MOVING THUNDERSTORMS AND GET TO SHORE QUICKLY
IF A STORM IS SIGHTED.

SCOTT
Special weather statement, Aug 11, 1:29 PM MDT, 48 minutes before
WYZ012-017-112015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
130 PM MDT SAT AUG 11 1990

...STRONG THUNDERSTORMS WERE RUMBLING IN PARTS OF SOUTHEAST WYOMING...

SCATTERED THUNDERSTORMS WERE OCCURRING OVER EXTREME SOUTHEAST WYOMING
EARLY THIS AFTERNOON.  AT 125 PM MDT...THE STRONGEST THUNDERSTORM WAS
ABOUT 10 MILES NORTHWEST OF CHEYENNE.  OTHER STRONG STORMS WERE NOTED
JUST WEST OF CHEYENNE AND AROUND THE CITY OF WHEATLAND.  ALL OF THE
THUNDERSTORMS WERE MOVING EAST AT 30 MILES AN HOUR.

NUMEROUS THUNDERSTORMS WILL CONTINUE IN SOUTHEAST WYOMING THROUGH THE
AFTERNOON AND EVENING HOURS.  SOME OF THESE STORMS WILL CONTAIN BRIEF
HEAVY RAIN...HAIL AND GUSTY WINDS.

PEOPLE IN SOUTHEAST WYOMING SHOULD KEEP AN EYE ON THE SKY FOR
THUNDERSTORM DEVELOPMENT THIS AFTERNOON AND EVENING.  SHOULD A STORM
APPROACH YOUR AREA...SEEK A SAFE PLACE IMMEDIATELY.

HATTEN

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 2:43 PM MDTSevere Thunderstorm WarningCYSGoshen, Platte32 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 1990Every severe thunderstorm warning in 1990

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.