Alert archive / Utah / Flash Flood Warnings in 1986

Flash Flood Warning 7, NWS Salt Lake City, UT

August 20, 19865 counties in Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 20, 1986, 8:28 PM MDT for 5 counties in Utah. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Aug 20, 1986, 8:28 PM MDT (02:28 UTC)
Expired
Aug 20, 1986, 11:00 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Whole counties

Counties Davis County, UT, Morgan County, UT, Salt Lake County, UT, Tooele County, UT, Weber County, UT

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

Salt Lake City I, UT (KSLC), launched 00:00Z, 2.5 hours before the alert went out and 23 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 1986-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 143 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 1986-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 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
143 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
2326 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

000 
TTAAOO KSLC 210228
FFWSLC
UTC051-011-029-033-035-043-057-045-210630-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
828 PM MDT WED AUG 20 1986
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 1100 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTIES:
 
IN NORTHERN UTAH
          ..DAVIS..MORGAN..SOUTHERN RICH
          ..SALT LAKE..WESTERN SUMMIT..WEBER
          ..NORTHERN WASATCH..EASTERN TOOELE

 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES, DIPS, OR LOW SPOTS IF WATER COVERS THE
ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM, EVEN A SMALL ONE,
ON FOOT.  TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.
 
HEAVY RAIN HAS BEEN REPORTED IN MANY AREAS OF NORTHWEST AND
NORTHCENTRAL UTAH THIS EVENING WITH A HALF INCH TO AN INCH OCCURING
WITHIN A SHORT PERIOD OF TIME. ADDITIONAL MODERATE TO BRIEF HEAVY
RAINS ARE LIKELY AND WILL ACCELERATE THE RUNOFF OF WATER OFF OF
ALREADY SATURATED GROUND.
 
MUDSLIDES AREA ALSO POSSIBLE IN THIS SITUATION...ESPECIALLY UP THE
CANYONS. EXTREME CAUTION SHOULD BE TAKEN FOR THOSE VENTURING OUT
WITHIN THE NEXT FEW HOURS.

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 20, 2:36 PM MDT, 5 hours 52 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
235 PM MDT WED AUG 20 1986

..AN ACTIVE THUNDERSHOWER DAY LIKELY IN THE NORTHWEST HALF OF UTAH..

THUNDERSHOWERS ARE ON THE INCREASE OVER UTAH AND WILL BECOME SCATTERED
TO NUMEROUS THE REMAINDER OF THE AFTERNOON UNTIL ABOUT MIDNIGHT
IN THE NORTHWEST HALF OF THE STATE. IN AN AREA NORTH OF A LINE FROM
THE UINTA MOUNTAINS TO ABOUT BRYCE CANYON SHOULD BE THE MOST ACTIVE
AREA OF THUNDERSHOWERS.

MODERATE TO LOCALLY HEAVY RAINS ARE POSSIBLE FROM THESE THUNDERSHOWERS
AND BRIEF GUSTY WINDS TO ABOUT 35 MPH. SOME SMALL HAIL IS ALSO POSSIBLE
FROM THE MORE ACTIVE CELLS.

FREQUENT LIGHTNING WILL BE ASSOCIATED WITH THESE SHOWERS. REMEMBER..
LIGHTNING IS UNFORGIVING AND A KILLER. TAKE PROPER PROTECTION IS
LIGHTNING IS IN THE AREA.. DON`T BE A HUMAN LIGHTNING ROD. MALES
IN THEIR TEENS AND 20S AND IN AN OPEN AREA ARE THE MOST LIKELY
LIGHTNING CANDIDATES.

ADDITIONAL STATEMENTS WILL BE ISSUED AS THE AFTERNOON PROGRESSES.

KML/WJA 2040Z....
Special weather statement, Aug 20, 6:00 PM MDT, 2 hours 28 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
600 PM MDT WED AUG 20 1986

       ...THUNDERSHOWERS RUMBLING IN FORCE...

THUNDERSHOWERS HAVE BECOME NUMEROUS OVER MUCH OF UTAH.
A FEW OF THESE HAVE PRODUCED BRIEF HEAVY RAIN IN THE SOUTHWESTERN
AND SOUTHCENTRAL PORTIONS OF THE STATE. SOME AMOUNTS REPORTED SINCE
THE MIDDLE OF THE AFTERNOON INCLUDE...A HALF INCH IN 35 MINUTES AT
PANGUITCH...0.44 IN 20 MINUTES AT LOA...0.48 IN 10 MINUTES AT SIGURD
...AND 0.70 AT GLENWOOD IN A HALF HOUR ALONG WITH PEA SIZED HAIL.

MODERATE TO LOCALLY HEAVY RAIN IS ALSO POSSIBLE IN THE NORTHERN
PORTION OF THE STATE AS WELL AS THE SOUTHWEST THROUGH THIS EVENING.

STRONG GUSTY WINDS...HAIL...AND FREQUENT LIGHTNING ARE POSSIBLE
FROM THESE THUNDERSTORMS. WIND GUSTS TO 33 MPH HAVE OCCURRED
AT THE PRICE AIRPORT AND TO 28 MPH AT THE WENDOVER AIRPORT.
SOME OF THE MORE INTENSE THUNDERSTORMS HAVE BEEN PRODUCING
MORE THAN ONE CLOUD TO GROUND LIGHTNING STRIKE PER MINUTE.

PERSONS IN UTAH SHOULD BE ALERT TO RAPIDLY CHANGING WEATHER AND BE
PREPARED TO MOVE TO A PLACE OF SAFETY IF THREATING WEATHER DEVELOPS.
REMEMBER...LIGHTNING IS AN UNFORGIVING KILLER.

FURTHER STATEMENTS WILL BE ISSUED ASe NEEDED.

JRP...2359Z

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 8:28 PM MDTFlash Flood WarningSLCSummit, Wasatch3 hr
Aug 20, 8:28 PM MDTFlash Flood WarningSLCRich3 hr

Nearby

Flash Flood Warnings in Utah, 1986Every flash flood warning in 1986

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.