Alert archive / Wyoming / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 96, NWS Cheyenne, WY

August 4, 1990Laramie County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 4, 1990, 3:24 PM MDT for Laramie County, Wyoming. It was in force for 41 min.

The area

The counties it named.

The facts

Issued
Aug 4, 1990, 3:24 PM MDT (21:24 UTC)
Expired
Aug 4, 1990, 4:05 PM MDT
In force
41 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, 9.4 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 1990-08-04Temperature 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 12:00Z on 1990-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -24 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2025 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-24 m²/s²
0-3 km storm-relative helicity
92 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 042126
SVRCYS
WYC021-042230-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
324 PM MDT SAT AUG 4 1990
 
THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  430 PM MDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST WYOMING
          ...SOUTHERN LARAMIE
 
AT 325 PM MDT RADAR INDICATED A SEVERE THUNDERSTORM 17 MILES WEST
OF CHEYENNE.  MOVEMENT OF THE THUNDERSTORM WAS EAST AT 15 MILES
AN HOUR.  THIS WARNING DOES INCLUDE THE CITY OF CHEYENNE.
 
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN ITS PATH YOU SHOULD
PREPARE FOR DAMAGING WIND IN0 EXCESS OF 55 MPH...LARGE HAIL...AND
DEADLY LIGHTNING.  PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT STAY AWAY FROM WINDOWS.
EKB

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 4, 9:34 AM MDT, 5 hours 50 minutes before
WYZALL-041800-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
935 AM MDT SAT AUG 4 1990

...STRONG THUNDERSTORMS ARE EXPECTED IN EASTERN WYOMING THIS
AFTERNOON...

THUNDERSTORMS ARE EXPECTED TO DEVELOP AGAIN THIS AFTERNOON ACROSS
MUCH OF WYOMING.  THE STRONGEST WILL BE IN THE EASTERN PART OF THE
STATE.  STRONG GUSTY WINDS...HAIL...AND LOCALLY BRIEF HEAVY RAIN ARE
POSSIBLE THERE.  DANGEROUS LIGHTNING CAN ALSO OCCUR.

PERSONSX PLANNING OUTDOOR ACTIVITIES THIS AFTERNOON...ESPECIALLY IN
EASTERN WYOMING...SHOULD BE AWARE OF POSSIBLE ADVERSE WEATHER
CONDITIONS.

CGB
Special weather statement, Aug 4, 9:37 AM MDT, 5 hours 47 minutes before
NEZ005-041630-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SCOTTSBLUFF NE
937 AM MDT FRI AUG 4 1990

...A STRONG THUNDERSTORM IN THE CENTRAL NEBRASKA PANHANDLE...

AT 935 AM MDT SHOWERS AND THUNDERSTORMS EXTENDED FROM 30 MILES WEST
OF CHADRON NEBRASKA TO 5 MILES NORTHWEST OF SCOTTSBLUFF TO ALLIANCE
NEBRASKA.  THE STRONGEST STORM WAS LOCATED 7 MILES NORTHWEST OF
SCOTTSBLUFF NEBRASKA IN NORTHERN SCOTTS BLUFF COUNTY.  ALL OF THE
SHOWERS AND THUNDERSTORMS WERE MOVING TO THE SOUTHEAST AT 15 MILES
PER HOUR.

BRIEF HEAVY RAIN...GUSTY WIND...DANGEROUS LIGHTNING CAN BE EXPECTD WITH
WITH THE THUNDERSTORMS AS THEY MOVE ACROSS THE NORTH AND CENTRAL
NEBRASKA PANHANDLE UNTIL 1030 AM MDT.
PEEK
^
Special weather statement, Aug 4, 12:37 PM MDT, 2 hours 47 minutes before
WYZALL-042000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
1240 PM MDT SAT AUG 4 1990

...THUNDERSTORMS HAVE BEGUN IN WYOMING...

AS EXPECTED THUNDERSTORMS HAVE BEGUN TO FIRE AT A NUMBER LOCATIONS.
THE YELLOWSTONE AREA IN NORTHWEST WYOMING...THE BIG HORN MOUNTAINS
IN THE NORTH AND PARTS OF CENTRAL WYOMING ARE REPORTING THUNDER.

THUNDERSTORMS WILL INCREASE IN NUMBER AND INTENSITY THIS AFTERNOON
MAINLY IN THE CENTRAL AND EAST. THE AREA BETWEEN LANDER AND CASPER
AS WELL AS THE EAST SLOPES OF THE LARAMIE RANGE ALONG INTERSTATE 25
WILL BE FAVORED AREAS FOR DEVELOPMENT. SOUTHEAST WYOMING COULD VERY
WELL HAVE SOME SEVERE THUNDERSTORMS ALONG WITH VERY HEAVY RAIN.

THUNDERSTORMS WILL MOVE SOUTHEAST VERY SLOWLY WHICH COULD PRODUCE
LOCALLY HEAVY RAINFALL AND LEAD TO LOCALIZED FLOODING.
<
PEOPLE IN EAST WYOMING SHOULD KEEP CLOSE TABS ON DEVELOPING WEATHER
THROUGH THE AFTERNOON AND EARLY EVENING AND BE READY TO SEEK INDOORj
SHELTER IF THREATENING WEATHER APPEARS.
CAS

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; the sounding from the Mesonet's radiosonde archive.