Alert archive / Utah / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 53, NWS Salt Lake City, UT

July 21, 1998Washington County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 21, 1998, 6:33 PM MDT for Washington County, Utah. It was in force for 42 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
Jul 21, 1998, 6:33 PM MDT (00:33 UTC)
Expired
Jul 21, 1998, 7:15 PM MDT
In force
42 min
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), 88 km from the middle of the area, began a volume at 00:37 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 00:00Z, 0.6 hours before the alert went out and 212 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 1998-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 112 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, Mercury/Desert R, NV at 00:00Z on 1998-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 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
112 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
3054 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
34 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.

421 
WUUS1 KSLC 220038 RRA
SVRSLC
UTC053-220115-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
633 PM MDT TUE JUL 21 1998

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

   * SEVERE THUNDERSTORM WARNING FOR...
     CENTRAL WASHINGTON COUNTY IN UTAH

   * UNTIL 715 PM MDT

   * AT 625 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
     SEVERE THUNDERSTORM 5 MILES NORTH OF SANTA CLARA...OR ABOUT 9
     MILES NORTHWEST OF ST GEORGE...MOVING SOUTH AT 10 MILES PER     
     HOUR.

   * SEVERE THUNDERSTORM WILL BE...
     IN THE VICINITY OF SANTA CLARA BY 645 PM MDT AND IN JUST WEST   
     OF ST GEORGE BY 715 PM MDT.

THIS STORM IS EXPECTED TO PRODUCE LARGE HAIL AND HEAVY RAIN AND MAY 
CAUSE MINOR STREET FLOODING.

LAT...LON 3711 11385 3711 11350 3726 11361 3726 11375

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 22, 2:35 PM MDTFlash Flood WarningSLCGarfield55 min
Jul 22, 3:30 PM MDTFlash Flood WarningSLCWayne2 hr

Nearby

Severe Thunderstorm Warnings in Utah, 1998Every severe thunderstorm 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.