Alert archive / Utah / Flash Flood Warnings in 1998

Flash Flood Warning 5, NWS Salt Lake City, UT

July 21, 1998Washington County, Utah

NWS Salt Lake City, UT issued this flash flood warning at Jul 21, 1998, 5:41 PM MDT for Washington County, Utah. It was in force for 3 hr. 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
Jul 21, 1998, 5:41 PM MDT (23:41 UTC)
Expired
Jul 21, 1998, 8:45 PM MDT
In force
3 hr
Issued by
NWS Salt Lake City, UT
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Washington County, UT

The radar

The Cedar City radar (KICX), 77 km from the middle of the area, began a volume at 23:44 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Mercury/Desert R, NV (KDRA), launched 12:00Z, 11.7 hours before the alert went out and 221 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 12:00Z on 1998-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 122 joules per kilogram.LCLLFCEL10008507005003002001001 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, Mercury/Desert R, NV at 12:00Z on 1998-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
122 J/kg
Mixed-layer CIN
-198 J/kg
Mixed-layer LCL
2317 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-5 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 212350
FFWSLC
UTC053-220245-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
541 PM MDT TUE JUL 21 1998

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

   * FLASH FLOOD WARNING FOR...
     CENTRAL WASHINGTON COUNTY IN UTAH

   * UNTIL 845 PM MDT

   * AT 540 PM MDT WEATHER SERVICE DOPPLER RADAR INDICATED VERY HEAVY
     RAIN OVER THE PINE VALLEY WILDERNESS AREA.  RADAR ESTIMATES     
     INDICATE THAT AS MUCH AS 3 INCHES OF RAIN HAVE FALLEN IN THE    
     AREA SINCE 430 PM MDT.

   * THE SANTA CLARA RIVER ABOVE BAKER DAM RESERVOIR AND SMALLER     
     STREAMS AND DRY WASHES FEEDING INTO THE UPPER REACHES OF THE    
     SANTA CLARA WILL BE AFFECTED

REMEMBER THAT FLASH FLOODING CAN OCCUR FAR REMOVED FROM THE 
THUNDERSTORM AND HOURS AFTER THE RAIN FELL.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE. IF YOUR VEHICLE STALLS, ABANDON IT IMMEDIATELY AND SEEK
HIGHER GROUND.


LAT...LON 3730 11382 3721 11350 3736 11352 3748 11370

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 6:53 PM MDTSevere Thunderstorm WarningSLCIron42 min
Jul 21, 2:15 PM MDTSevere Thunderstorm WarningSLCSan Juan45 min
Jul 21, 3:07 PM MDTSevere Thunderstorm WarningSLCKane, Washington38 min
Jul 21, 3:30 PM MDTFlash Flood WarningSLCWashington2 hr
Jul 21, 4:50 PM MDTFlash Flood WarningSLCWashington3 hr
Jul 21, 5:10 PM MDTSevere Thunderstorm WarningSLCWashington50 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; radar from the NEXRAD Level II archive.