Alert archive / Utah / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 21, NWS Salt Lake City, UT

August 27, 1991Box Elder County, Tooele County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Aug 27, 1991, 6:47 PM MDT for Box Elder County, Tooele County, Utah. It was in force for 58 min.

The area

The counties it named.

The facts

Issued
Aug 27, 1991, 6:47 PM MDT (00:47 UTC)
Expired
Aug 27, 1991, 7:45 PM MDT
In force
58 min
Issued by
NWS Salt Lake City, UT
Area
Whole counties

Counties Box Elder County, UT, Tooele County, UT

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 00:00Z, 0.8 hours before the alert went out and 104 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, Salt Lake City I, UT at 00:00Z on 1991-08-28Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 00:00Z on 1991-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 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
1769 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
246 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSLC 280048
SVRSLC
UTC003-045-280145-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
647 PM MDT TUE AUG 27 1991
 
THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  745 PM MDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN NORTHWEST UTAH
 
   ...WESTERN BOX ELDER COUNTY...NORTHWESTERN TOOELE COUNTY
 
A LINE OF THUNDERSTORMS MOVING THROUGH NORTHWEST TOOELE COUNTY INTO
WESTERN BOX ELDER COUNTY ARE PRODUCING VERY STRONG WINDS. AT 628 PM AT
THE WENDOVER AIRPORT AN AUTOMATIC WIND INSTRUMENT RECORDED A GUST TO
56 MPH FROM A NEARBY THUNDERSTORM.
 
THE LINE OF THUNDERSTORMS IS MOVING TOWARDS THE NORTHEAST AND EVEN
THOUGH PARTS OF THE COUNTIES MENTIONED HAVE SPARSE
POPULATION...RESIDENTS OR TRAVELERS SHOULD BE VERY CAUTIOUS AND TAKE
SHELTER WHEN STORMS APPROACH.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIjVE 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.
 
SMITH/0048Z..

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 27, 2:00 PM MDT, 4 hours 47 minutes before
UTZALL-280300-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
200 PM MDT TUE AUG 27 1991

       ...SEVERE THUNDERSTORM WATCH UNTIL 9 PM MDT...

THE NATIONAL SEVERE STORMS FORECAST CENTER IN KANSAS CITY HAS ISSUED
A SEVERE THUNDERSTORM WATCH UNTIL 9 PM MDT THIS EVENING FOR NORTHWEST
UTAH EXTREME NORTHEAST NEVADA AND EASTERN IDAHO.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE
FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. SHOULD
CONDITIONS WARRANT...A SEVERE THUNDERSTORM WARNING WILL BE ISSUED.

SEVERE THUNDERSTORMS CAN PRODUCE STRONG WINDS AND LARGE HAIL. HEAVY
RAINFALL IS ALSO POSSIBLE WHICH CAN CAUSE LOCALIZED FLOODING
DEPENDING ON THE LOCATION. THESE STORMS ARE ALSO EXPECTED TO PRODUCE
FREQUENT LIGHTNING STRIKES.

LATEST LIGHTNING DETECTION CHARTS INDICATE AN ACTIVE AREA OF
THUNDERSHOWER CELLS MOVING INTO THE SOUTH END OF THE WASATCH FRONT.
NEARLY 50 CLOUD-TO-GROUND LIGHTNING STRIKES IN THE PERIOD FROM 1:15
TO 1:45 PM MDT.  THIS AREA IS MOVING TO THE NORTH.

REMEMBER LIGHTNING IS A PROVEN KILLER.  SO FAR THIS SUMMER 3 PEOPLE
IN UTAH HAVE BEEN KILLED BY LIGHTNING AND 4 HAVE BEEN INJURED.  DON'T
ADD TO THESE FIGURES.  TAKE PROPER PROTECTION TO AVOID BEING A HUMAN
LIGHTNING ROD.

PERSONS IN THE WATCH AREA SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS. SHOULD SEVERE
WEATHER OCCUR IN YOUR AREA REPORT IT TO THE NEAREzST LAW ENFORCEMENT
AGENCY OR THE NATIONAL WEATHER SERVICE.

FURTHER STATEMENTS WILL BE ISSUED AS NEEDED.

DJ/WJA 2000Z....
Special weather statement, Aug 27, 5:45 PM MDT, 1 hour 2 minutes before
UTZALL-280200-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
545 PM MDT TUE AUG 27 1991

...SEVERE THUNDERSTORM WATCH AND URBAN AND SMALL STREAM FLOODING
ADVISORY UNTIL 9 PM MDT...

A SEVERE THUNDERSTORM WATCH FOR NORTHWEST UTAH REMAINS IN EFFECT
UNTIL 9 PM TONIGHT.  A WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR
THE DEVELOPMENT OF SEVERE THUNDERSTORMS.

ALSO AN URBAN AND SMALL STREAM FLOODING ADVISORY FOR THE WASATCH
FRONT AND CACHE VALLEY REMAINS IN EFFECT UNTIL 9 PM TONIGHT.

AN APPROACHING UPPER AIR WEATHER SYSTEM HAS PUSHED A COLD FRONT TO
THE NEVADA UTAH BORDER.  THUNDERSTORMS ALONG AND AHEAD OF THE COLD
FRONT WILL SWING THROUGH NORTHWEST UTAH THIS EVENING BRINGING THE
POTENTIAL FOR VERY STRONG WINDS...LARGE HAIL...AND HEAVY RAIN.

RESIDENTS AND TRAVELERS THROUGH NORTHWEST UTAH NEED TO REMAIN ALERT
FOR POTENTIALLY DANGEROUS WEATHER CONDITIONS INCLUDING FREQUENT
LIGHTNING.  IF POSSIBLE SEEK SHELTER INDOORS WHEN STORMS APPROACH AND
NEVER ATTEMPT TO CROSS FLOODED ROADS IN YOUR CAR.  BRIEF HEAVY RAINS
ASSOCIATED WITH THE THUNDERSTORMS WILL LIKELY CAUSE LOW LYING
AREAS...SMALL STREAMS...AND STREET INTERSECTIONS TO FILL OR EVEN
OVERFLOW.  MOVE TO HIGHER GROUND OF WATERS RISE.

THUNDERSTORMS HAVE ALSO DEVELOPED IN SOUTHERN AND EASTERN UTAH THIS
AFTERNOON AND BRIEF HEAVY RAINS WITH STRONG GUSTY WINDS ARE ALSO
POSSIBLE NEAR THUNDERSHOWERS IN THAT AREA.

ADDITIONAL STATEMENTS WILL BE ISSUED ABOUT THIS DEVELOPING WEATHER
SITUATION.

SMITH/2345Z..
Special weather statement, Aug 27, 6:30 PM MDT, 17 minutes before
UTZALL-280300-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
630 PM MDT TUE AUG 27 1991

...SEVERE THUNDERSTORM WATCH AND URBAN AND SMALL STREAM FLOODING
ADVISORY UNTIL 9 PM MDT...

A SEVERE THUNDERSTORM WATCH FOR NORTHWEST UTAH REMAINS IN EFFECT
UNTIL 9 PM TONIGHT.  A WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR
THE DEVELOPMENT OF SEVERE THUNDERSTORMS.

ALSO AN URBAN AND SMALL STREAM FLOODING ADVISORY FOR THE WASATCH
FRONT AND CACHE VALLEY REMAINS IN EFFECT UNTIL 9 PM TONIGHT.

AT 615 PM A LINE OF THUNDERSTORMS WAS DEVELOPING FROM NORTHWEST OF
DELTA TO THE NORTHWEST CORNER OF THE STATE.  THIS PUTS THE LINE OF
THUNDERSTORMS ABOUT 75 MILES FROM THE WASATCH FRONT AND PRESENT
MOVEMENT WOULD BRING THESE THUNDERSTORMS TO THE WASATCH FRONT BETWEEN
8 AND 9 PM TONIGHT.
THERE WERE ALSO SOME STRONG THUNDERSTORMS MOVING THROUGH THE
NORTHEAST PART OF THE STATE WITHIN THE LAST HOUR.  RAINFALL IN UINTAH
COUNTY WAS GENERALLY .15 OF AN INCH TO .40 OF AN INCH WITHIN 30
MINUTES TIME.  ONE OBSERVER 12 MILES EAST OF MYTON RECEIVED .90 OF AN
INCH BETWEEN 530 AND 600 PM.  THERE WAS NO FLOODING REPORTED IN THE
AREA.

RESIDENTS AND TRAVELERS THROUGH NORTHERN UTAH NEED TO REMAIN ALERT
FOR POTENTIALLY DANGEROUS WEATHER CONDITIONS INCLUDING FREQUENT
LIGHTNING.  IF POSSIBLE SEEK SHELTER INDOORS WHEN STORMS APPROACH AND
NEVER ATTEMPT TO CROSS FLOODED ROADS IN YOUR CAR.  BRIEF HEAVY RAINS
ASSOCIATED WITH THE THUNDERSTORMS WILL LIKELY CAUSE LOW LYING
AREAS...SMALL STREAMS...AND STREET INTERSECTIONS TO FILL OR EVEN
OVERFLOW.  MOVE TO HIGHER GROUND IF WATERS RISE.

ADDITIONAL STATEMENTS WILL BE ISSUED ABOUT THIS DEVELOPING WEATHER
SITUATION.

SMITH/0030Z..

Nearby

Severe Thunderstorm Warnings in Utah, 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.