Alert archive / Utah / Flash Flood Warnings in 1991

Flash Flood Warning 2, NWS Salt Lake City, UT

August 1, 1991Sevier County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 1, 1991, 10:40 PM MDT for Sevier County, Utah. It was in force for 80 min.

The area

The counties it named.

The facts

Issued
Aug 1, 1991, 10:40 PM MDT (04:40 UTC)
Expired
Aug 2, 1991, 12:00 AM MDT
In force
80 min
Issued by
NWS Salt Lake City, UT
Area
Whole counties

County Sevier County, UT

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 00:00Z, 4.7 hours before the alert went out and 226 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 1991-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 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, Salt Lake City I, UT at 00:00Z on 1991-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
2308 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
11 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 KSLC 020452
FFWSLC
UTC041-020600-

BULLETIN...IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1040 PM MDT THU AUG 1 1991

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING EFFECTIVE
UNTIL MIDNIGHT FOR THE NORTHERN HALF OF SEVIER COUNTY.

A FLASH FLOOD WARNING MEANS FLASH FLOODING IS OCCURRING.  THE UTAH
HIGHWAY PATROL REPORTS FLASH FLOODING IN SALINA.  THEY ESTIMATED
2 INCHES OF RAIN HAS FALLEN IN THE LAST HOUR IN SALINA. THE THUNDERSTORM
THAT CAUSED THIS HEAVY RAIN IS MOVING OFF TO THE EAST AND RAINFALL
SHOULD BE DECREASING SOON.

HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE
WATER IS COVERING THE ROAD.

EC...0445Z

What forecasters said that day

The local office's own words before this flash flood 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, 5:41 PM MDT, 4 hours 59 minutes before
UTZALL-020500-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
538 PM MDT THU AUG 1 1991

 ...THUNDERSHOWERS WILL CONTINUE OVER PORTIONS OF UTAH TONIGHT...

A VERY MOIST AND UNSTABLE AIRMASS CONTINUES OVER MUCH OF UTAH THIS
EVENING.  AT 5 PM SATELLITE IMAGERY SHOWED A STRONG THUNDERSTORM
MOVING OUT OF NORTHEAST GRAND COUNTY INTO COLORADO.  THIS
THUNDERSTORM HAD ALREADY CAUSED UNCONFIRMED GUSTS TO 67 MPH.

IN ADDITION A VERY LONG LINE OF THUNDERSTORMS STRETCHES FROM JUST
NORTH OF LAS VEGAS TO ABOUT DUGWAY PROVING GROUND.  THIS LINE IS
SHIFTING RAPIDLY NORTHEASTWARD AND DEVELOPING.  THESE THUNDERSTORMS
WILL BE MOVING INTO NORTHWEST AND WEST CENTRAL UTAH THE NEXT SEVERAL

HOURS AND COULD CAUSE STRONG GUSTY WINDS...LOCALLY HEAVY RAIN AND
DANGEROUS LIGHTNING.  WHILE THE MAIN ACTIVITY TONIGHT WILL LIKELY
BE IN NORTHWEST AND WEST CENTRAL UTAH...THE POTENTIAL EXISTS FOR
ALMOST ANY AREA OF THE STATE TO HAVE THUNDERSTORMS DEVELOP.

RESIDENTS OF UTAH SHOULD MAINTAIN A HIGH AWARENESS OF THE WEATHER
SITUATION TONIGHT.  REMEMBER...IF YOU ARE CAUGHT OUTSIDE IN A
THUNDERSTORM...DO NOT STAND UNDERNEATH A TALL ISOLATED TREE OR A
TELEPHONE POLE.  ALSO RAIN FROM STRONG THUNDERSTORMS CAN FLOOD
ROADS QUICKLY.  DO NOT ATTEMPT TO DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

ADDITIONAL STATEMENTS OR ADVISORIES WILL BE ISSUED AS NEEDED.

ERC...2338Z
Special weather statement, Aug 1, 8:25 PM MDT, 2 hours 15 minutes before
UTZALL-020500-
SPECIAL WEATHER STATEMENT AND UTAH WEATHER SUMMARY
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
820 PM MDT THU AUG 1 1991

     ...THUNDERSHOWERS CONTINUING OVER PORTIONS OF UTAH...

A VERY MOIST AND UNSTABLE AIRMASS CONTINUES OVER MUCH OF UTAH.
AT 8 PM SATELLITE IMAGERY INDICATED THE MAIN THUNDERSTORM ACTIVITY
WAS OVER WEST CENTRAL UTAH.  AT 730 PM A FLASH FLOOD SPOTTER IN DELTA
REPORTED .50 INCHES OF RAIN IN 25 MINUTES.  STRONG THUNDERSTORMS WERE
ALSO LOCATED JUST EAST OF THE FOUR-CORNERS AREA AND JUST SOUTH OF THE
SOUTHERN END OF LAKE POWELL.  NONE OF THESE THUNDERSTORMS WERE SHOWING
MUCH MOVEMENT.

ACTIVITY IN NORTHWEST UTAH HAD BECOME MINIMAL AS THE FLOW ALOFT HAS
TURNED TO THE NORTHWEST WITH MUCH DRIER AND MORE STABLE AIR MOVING
INTO THE AREA.  SCATTERED THUNDERSTORMS ARE EXPECTED TO CONTINUE
OVER THE STATE BEFORE DIMINISHING AROUND MIDNIGHT.

EXCEPT FOR EXTREME NORTHWEST UTAH...ALMOST ANY PART OF THE STATE
COULD SEE SOME THUNDERSTORM DEVELOPMENT UNTIL ABOUT MIDNIGHT.

DUE TO THE VERY MOIST AND UNSTABLE AIRMASS OVER MOST OF THE STATE...
LOCALLY HEAVY RAIN...GUSTY WINDS...AND DANGEROUS LIGHTNING WILL
ACCOMPANY MANY OF THE THUNDERSTORMS.

REMEMBER...LIGHTNING IS A PROVEN KILLER...DO NOT BECOME A HUMAN
LIGHTNING ROD...KEEP AWAY FROM OPEN WATER...TRACTORS AND OTHER FARM
EQUIPMENT.

ADDITIONAL STATEMENTS OR ADVISORIES WILL BE ISSUED AS NEEDED.

ERC...0222Z

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 2, 4:40 PM MDTFlash Flood WarningSLCGrand, Uintah2 hr

Nearby

Flash Flood Warnings in Utah, 1991Every flash flood 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.