Alert archive / Wyoming / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 87, NWS Cheyenne, WY

August 1, 1990Carbon County, Wyoming

NWS Cheyenne, WY issued this severe thunderstorm warning at Aug 1, 1990, 5:35 PM MDT for Carbon County, Wyoming. It was in force for 40 min.

The area

The counties it named.

The facts

Issued
Aug 1, 1990, 5:35 PM MDT (23:35 UTC)
Expired
Aug 1, 1990, 6:15 PM MDT
In force
40 min
Issued by
NWS Cheyenne, WY
Area
Whole counties

County Carbon 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

Lander/Hunt Fiel, WY (KLND), launched 12:00Z, 11.6 hours before the alert went out and 192 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, Lander/Hunt Fiel, WY at 12:00Z on 1990-08-01Temperature 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 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lander/Hunt Fiel, WY at 12:00Z on 1990-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
2232 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
45 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 012336
SVRCYS
WYC007-020015-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHEYENNE WY
535 PM MDT WED AUG 1 1990
 
THE NATIONAL WEATHER SERVICE IN CHEYENNE HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  615 PM MDT
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTH CENTRAL WYOMING
          ...WESTERN CARBON
 
AT 520 PM MDT A THUNDERSTORM WEST OF RAWLINS PRODUCED A WIND GUST TO
58 MILES AN HOUR. THE STORMS HAVE BEEN MOVING EAST AT 25 MILES AN
HOUR.
 
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN ITS PATH YOU SHOULD
PREPARE FOR DAMAGING WIND IN EXCESS OF 55 MPH...AND
DEADLY LIGHTNING.  PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT STAY AWAY FROM WINDOWS.

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 1, 4:06 PM MDT, 1 hour 29 minutes before
WYZ012-017-012300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
405 PM MDT WED AUG 1 1990

...INTENSE THUNDERSTORMS DEVELOPING OVER SOUTHEAST WYOMING...

STRONG THUNDERSTORMS WERE DEVELOPING OVER SOUTHEAST WYOMING THIS
AFTERNOON.  THE MOST INTENSE STORM WAS LOCATED JUST EAST OF
CHUGWATER WYOMING OR ABOUT 40 NORTH OF CHEYENNE. THE STORM WAS
MOVING TO THE NORTHEAST AT 20 MPH.

OTHER STORMS WERE DEVELOPING IN LARAMIE COUNTY ABOUT 20 MILES
EAST AND WEST OF THE CITY OF CHEYENNE.  EARLIER TODAY PEA-SIZE
HAIL AND BRIEF HEAVY RAINS WERE OBSERVED WITH THESE STORMS.

PEOPLE IN SOUTHEAST WYOMING SHOULD BE ON THE LOOKOUT FOR POTENTIALLY
THREATENING WEATHER.  HAIL...DEADLY LIGHTNING] AND HEAVY RAINS ARE
POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING IN AND AROUND THESE
STORMS.
PARKER
Special weather statement, Aug 1, 5:29 PM MDT, 6 minutes before
WYZ017-020000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
530 PM MDT WED AUG 1 1990

...STRONG THUNDERSTORMS IN EASTERN LARAMIE COUNTY...

RADAR INDICATED A VERY STRONG THUNDERSTORM JUST WEST OF PINE BLUFFS
WYOMING OR ABOUT 35 MILES EAST OF CHEYENNE.  THE STORM WILL MOVE
INTO THE PINE BLUFFS AREA BETWEEN 530 AND 6 PM.  VERY HEAVY RAIN...
HAIL...GUSTY WINDS AND FREQUENT LIGHTNING WILL BE WITH THE STORM.

PEOPLE IN SOUTHEAST WYOMING SHOULD BE ON THE LOOKOUT FOR POTENTIALLY
THREATENING WEATHER.  HAIL...DEADLY LIGHTNING AND HEAVY RAINS ARE
POSSIBLE THIS AFTERNOON AND EARLY THIS EVENING IN AND AROUND THESE
STORMS.

SCOTT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 1, 3:25 PM MDTSevere Thunderstorm WarningCYSSweetwater65 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; the sounding from the Mesonet's radiosonde archive.