Alert archive / Nebraska / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 13, NWS Cheyenne, WY

May 10, 1991Sioux County, Nebraska

NWS Cheyenne, WY issued this severe thunderstorm warning at May 10, 1991, 8:33 PM MDT for Sioux County, Nebraska. It was in force for 57 min.

The area

The counties it named.

The facts

Issued
May 10, 1991, 8:33 PM MDT (02:33 UTC)
Expired
May 10, 1991, 9:30 PM MDT
In force
57 min
Issued by
NWS Cheyenne, WY
Area
Whole counties

County Sioux County, NE

The nearest sounding before it

Rapid City, SD (KRAP), launched 00:00Z, 2.6 hours before the alert went out and 190 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 1991-05-11Temperature 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 00:00Z on 1991-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 294 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
2978 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
294 m²/s²
0-3 km storm-relative helicity
325 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 KBFF 110233
SVRBFF
NEC165-110330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING 
NATIONAL WEATHER SERVICE SCOTTSBLUFF NE
833 PM MDT FRI MAY 10 1991

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM 
WARNING EFFECTIVE UNTIL 930 PM MDT FOR PEOPLE IN THE FOLLOWING 
COUNTY

   IN THE PANHANDLE OF NEBRASKA
      NORTHERN SIOUX

AT 830 PM MDT...SEVERE THUNDERSTORMS WERE LOCATED FROM 20 MILES
NORTHWEST TO 55 MILES SOUTHWEST OF CHADRON NEBRASKA.  THE STRONGEST
STORMS WERE FROM 20 MILES NORTHEAST TO 25 MILES SOUTH OF THE TOWN
OF HARRISON NEBRASKA IN SIOUX COUNTY.  THE STORMS WERE ALMOST
STATIONARY...SHOWING LITTLE IF ANY MOVEMENT.

IF THREATENING WEATHER APPROACHES...TAKE SHELTER INSIDE A REINFORCED
BUILDING.  STAY AWAY FROM WINDOWS.  A BASEMENT...INTERIOR HALLWAY...
OR A ROOM ON THE LOWEST FLOOR IS THE SAFEST PLACE IN MOST BUILDINGS.
MOTORISTS SHOULD AVOID LOW WATER CROSSINGS.

A TORNADO WATCH IS ALSO IN EFFECT FOR T_HE WARNED AREA.  REMEMBER
THESE STORMS CAN AND OCCASIONALLY DO PRODUCE A TORNADO WITH LITTLE
OR NO ADVANCE WARNING.

PFEIFFER

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, May 10, 2:50 PM MDT, 5 hours 43 minutes before
WYZ012-017-110050-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
250 PM MDT FRI MAY 10 1991

...A TORNADO WATCH HAS BEEN ISSUED FOR EXTREME EASTERN WYOMING
UNTIL 9 PM THIS FRIDAY EVENING...

VERY STRONG THUNDERSTORM ARE EXPECT TO DEVELOP OVER PORTIONS OF
EASTERN WYOMING THE REST OF THE AFTERNOON AND EVENING. A FEW OF THESE
STORMS COULD PRODUCE BRIEF HEAVY RAIN AND HAIL. A TORNADO IS POSSIBLE
WITH ONE OF THESE STORMS.   THE MOST LIKELYHOOD OF SEVERE WEATHER IS
IN NIOBRARA...GOSHEN...LARAMIE OR EASTERN PLATTE COUNTY.

A TORNADO WATCH HAS BEEN POSTED FOR THE EASTERN COUNTIES AND INCLUDE
THE FOLLOWING CITIES IN THE WATCH AREA...TORRINGTON...LUSK...CHEYENNE
AND PINE BLUFFS.

NEAR 245 PM A STRONG THUNDERSTORM WAS NOTED ON RADAR IN SOUTHWESTERN
GOSHEN COUNTY MOVING TO THE NORTH AT NEARLY 30 MILES AN HOUR.

SGS
Special weather statement, May 10, 3:28 PM MDT, 5 hours 5 minutes before
WYZ012-017-110035-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
325 PM MDT FRI MAY 10 1991

...A TORNADO WATCH HAS BEEN ISSUED FOR EXTREME EASTERN WYOMING
UNTIL 9 PM THIS FRIDAY EVENING...

A LINE OF THUNDERSTORMS WAS LOCATED BY WEATHER RADAR IN NORTHERN
LARAMIE COUNTY AND IN SOUTHWEST GOSHEN COUNTY FRIDAY AFTERNOON.
HAILSTONES UP TO ONE HALF INCH WERE REPORTED FROM ONE OF THESE STORMS
AROUND 3 PM. THE LOCATION OF THE SMALL HAIL WAS 28 MILES NORTHEAST
OF CHEYENNE.

RADAR CONTINUED TO NOTED SCATTERED SHOWERS AND THUNDERSTORMS IN
SOUTHEAST WYOMING MOVING TO THE NORTH AT NEARLY 30 MILES AN HOUR.

SGS
Special weather statement, May 10, 5:41 PM MDT, 2 hours 52 minutes before
WYZ012-017-110100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
440 PM MDT FRI MAY 10 1991

...A TORNADO WATCH CONTINUES IN EFFECT FOR EXTREME EASTERN WYOMING
UNTIL 9 PM THIS EVENING...

THUNDERSTORMS CONTINUED OVER THE SOUTHEAST CORNER OF WYOMING LATE THIS
AFTERNOON. THE STRONGEST STORMS WERE ALONG INTERSTATE 25 HEADING NORTH
FROM CHEYENNE.  A PILOT OBSERVED A POSSIBLE FUNNEL CLOUD ABOUT 30 TO
35 MILES NORTH OF CHEYENNE.  RADAR INDICATED THESE STORMS WERE LIKELY
PRODUCING SMALL HAIL AS WELL.

THE THUNDERSTORMS THAT PRODUCED GOLF-BALL SIZE HAIL IN THE TORRINGTON
AREA EARLIER HAD MOVED NORTHEAST INTO NEBRASKA.  STRONG THUNDERSTORMS
WILL CONTINUE TO BE POSSIBLE OVER SOUTHEAST WYOMING THIS EVENING. A
TORNADO WATCH FOR THE EXTREME EAST WILL CONTINUE UNTIL 9 PM TONIGHT.

PEOPLE IN SOUTHEAST WYOMING SHOULD BE ALERT FOR THUNDERSTORM ACTIVITY
THIS EVENING AND TAKE SHELTER IF THUNDERSTORMS APPROACH.  LISTEN
TO NOAA WEATHER RADIO OR THE LOCAL MEDIA FOR ADDITIONAL INFORMATION
ON THE STORMS.

SCOTT
Special weather statement, May 10, 5:42 PM MDT, 2 hours 51 minutes before
WYZ012-017-110100-

SPECIAL WEATHER STATEMENT...CORRECTED FOR TIME
NATIONAL WEATHER SERVICE CHEYENNE WY
540 PM MDT FRI MAY 10 1991

...A TORNADO WATCH CONTINUES IN EFFECT FOR EXTREME EASTERN WYOMING
UNTIL 9 PM THIS EVENING...

THUNDERSTORMS CONTINUED OVER THE SOUTHEAST CORNER OF WYOMING LATE THIS
AFTERNOON. THE STRONGEST STORMS WERE ALONG INTERSTATE 25 HEADING NORTH
FROM CHEYENNE.  A PILOT OBSERVED A POSSIBLE FUNNEL CLOUD ABOUT 30 TO
35 MILES NORTH OF CHEYENNE.  RADAR INDICATED THESE STORMS WERE LIKELY
PRODUCING SMALL HAIL AS WELL.

THE THUNDERSTORMS THAT PRODUCED GOLF-BALL SIZE HAIL IN THE TORRINGTON
AREA EARLIER HAD MOVED NORTHEAST INTO NEBRASKA.  STRONG THUNDERSTORMS
WILL CONTINUE TO BE POSSIBLE OVER SOUTHEAST WYOMING THIS EVENING. A
TORNADO WATCH FOR THE EXTREME EAST WILL CONTINUE UNTIL 9 PM TONIGHT.

PEOPLE IN SOUTHEAST WYOMING SHOULD BE ALERT FOR THUNDERSTORM ACTIVITY
THIS EVENING AND TAKE SHELTER IF THUNDERSTORMS APPROACH.  LISTEN
TO NOAA WEATHER RADIO OR THE LOCAL MEDIA FOR ADDITIONAL INFORMATION
ON THE STORMS.

SCOTT
Special weather statement, May 10, 8:22 PM MDT, 11 minutes before
WYZ012-017-110300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
820 PM MDT FRI MAY 10 1991

...A TORNADO WATCH CONTINUES IN EFFECT FOR EXTREME EASTERN WYOMING
UNTIL 9 PM THIS FRIDAY EVENING...

AT 815 PM...WEATHER RADAR AT CHEYENNE SHOWED SOME LINGERING SHOWERS
AND THUNDERSTORMS ACROSS THE FAR NORTHERN PART OF PLATTE AND GOSHEN
COUNTIES.  STRONGEST STORMS WERE LOCATED IN THE NORTHEAST PART OF
GOSHEN COUNTY...ABOUT 35 MILES NORTH OF TORRINGTON.  A FEW OTHER WEAK
STORMS WERE LOCATED JUST WEST OF TORRINGTON ALSO.  ALL STORMS WERE
MOVING NORTH AT 35 MILES AN HOUR.

ONCE THESE STORMS EXIT THE WATCH AREA...THERE SHOULD BE NO OTHER
SIGNIFICANT THUNDERSTORMS IN SOUTHEAST WY}OMING.  HENCE...IT APPEARS
VERY LIKELY THAT THE TORNADO WATCH WILL BE ALLOWED TO EXPIRE AT 9 PM.

JAD

The office that day

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

IssuedProductOfficeCountiesLasted
May 10, 6:03 PM MDTFlash Flood WarningCYSDawes, Sioux4 hr
May 10, 6:33 PM MDTSevere Thunderstorm WarningCYSDawes, Sioux57 min
May 10, 7:34 PM MDTSevere Thunderstorm WarningCYSSioux56 min
May 10, 9:35 PM MDTSevere Thunderstorm WarningCYSDawes, Sioux55 min
May 10, 9:58 PM MDTFlash Flood WarningCYSDawes, Sioux4 hr
May 11, 3:46 PM MDTSevere Thunderstorm WarningCYSSioux59 min
May 11, 4:48 PM MDTSevere Thunderstorm WarningCYSSioux27 min
May 11, 5:41 PM MDTSevere Thunderstorm WarningCYSSioux34 min
May 11, 5:56 PM MDTSevere Thunderstorm WarningCYSBanner, Morrill64 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 1991Every severe thunderstorm warning in 1991

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.