Alert archive / Utah / Flash Flood Warnings in 1998

Flash Flood Warning 45, NWS Salt Lake City, UT

August 30, 1998Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Aug 30, 1998, 7:46 PM MDT for Washington County, Utah. It was in force for 74 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Aug 30, 1998, 7:46 PM MDT (01:46 UTC)
Expired
Aug 30, 1998, 9:00 PM MDT
In force
74 min
Issued by
NWS Salt Lake City, UT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Washington County, UT

The nearest sounding before it

Mercury/Desert R, NV (KDRA), launched 00:00Z, 1.8 hours before the alert went out and 224 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, Mercury/Desert R, NV at 00:00Z on 1998-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1125 joules per kilogram.LCLEL10008507005003002001001 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, Mercury/Desert R, NV at 00:00Z on 1998-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 136 square meters per square second.1939Sfc1 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
1125 J/kg
Mixed-layer CIN
-41 J/kg
Mixed-layer LCL
3052 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
136 m²/s²
0-3 km storm-relative helicity
170 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSLC 310156
FFWSLC
UTC053-310300-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
746 PM MDT SUN AUG 30 1998

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS EXTENDED THE

   * FLASH FLOOD WARNING FOR...
     CENTRAL WASHINGTON COUNTY IN UTAH
     INCLUDING ST GEORGE

   * UNTIL 900 PM MDT

   * AT 739 PM MDT VERY HEAVY RAIN WAS STILL OCCURRING IN THE WARNING 
     AREA. 

   * OTHER LOCATIONS IN THE WARNING INCLUDE WASHINGTON...
     TOQUERVILLE...SANTA CLARA...GUNLOCK AND HURRICANE

HEAVY RAINS HAVE CAUSED EXTENSIVE MINOR FLOODING WITH SEVERAL AREAS 
REPORTING SIGNIFICANT FLOODING. COUNTY SHERIFFS ARE BARRACADING 
PORTIONS OF OLD HIGHWAY 91 IN THE TOWN OF WASHINGTON DUE TO WATER 
OVER THE ROAD. 

EXCESSIVE RUNOFF FROM THESE RAINS WILL CAUSE FLASH FLOODING OF SMALL 
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES...AND OTHER LOW LYING 
AREAS. 

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 OTHER LOW SPOTS IF WATER COVERS
THE ROADWAY. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT. TO ESCAPE RISING WATEfR MOVE UP TO HIGHER GROUND.

STAY TUNED TO LOCAL TELEVISION...RADIO...CABLE TV...OR NOAA WEATHER 
RADIO FOR UPDATES.

LAT...LON 3701 11384 3701 11314 3731 11319 3743 11383

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 30, 6:28 PM MDTSevere Thunderstorm WarningSLCWashington32 min
Aug 30, 6:57 PM MDTFlash Flood WarningSLCWashington63 min

Nearby

Flash Flood Warnings in Utah, 1998Every flash flood warning in 1998

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.