Alert archive / Utah / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 104, NWS Salt Lake City, UT

September 12, 1998San Juan County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Sep 12, 1998, 2:42 PM MDT for San Juan County, Utah. It was in force for 18 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 12, 1998, 2:42 PM MDT (20:42 UTC)
Expired
Sep 12, 1998, 3:00 PM MDT
In force
18 min
Issued by
NWS Salt Lake City, UT
Area
Whole counties

County San Juan County, UT

The radar

The Grand Junction radar (KGJX), 212 km from the middle of the area, began a volume at 20:43 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

Grand Junction, CO (KGJT), launched 12:00Z, 8.7 hours before the alert went out and 202 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, Grand Junction, CO at 12:00Z on 1998-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 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, Grand Junction, CO at 12:00Z on 1998-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 101 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
67 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
673 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
101 m²/s²
0-3 km storm-relative helicity
113 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.

453 
WUUS1 KSLC 122046 RRA
SVRSLC
UTC037-122100-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
242 PM MDT SAT SEP 12 1998

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

   * THE SEVERE THUNDERSTORM WARNING HAS BEEN EXTENDED FOR...
     EAST CENTRAL SAN JUAN COUNTY IN UTAH

   * UNTIL 300 PM MDT

   * AT 232 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
     SEVERE THUNDERSTORM 7 MILES SOUTH OF EASTLAND...OR ABOUT 14
     MILES SOUTHEAST OF MONTICELLO...MOVING NORTHEAST AT 30 MILES PER
     HOUR.

   * OTHER LOCATIONS IN THE WARNING INCLUDE EASTLAND

LARGE HAIL IS POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF YOU ARE 
IN THE PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A 
SUBSTANTIAL SHELTER.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH YOU SHOULD PREPARE
FOR DAMAGING WINDS IN EXCESS OF 55 MPH...LARGE HAIL...AND DEADLY
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN SALT LAKE CITY.

LAT...LON 3785 10933 3756 10910 3786 10856 3806 10870

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 12, 11:43 AM MDTSevere Thunderstorm WarningSLCSan Juan17 min
Sep 12, 2:19 PM MDTSevere Thunderstorm WarningSLCSan Juan26 min
Sep 12, 2:29 PM MDTSevere Thunderstorm WarningSLCDavis, Salt Lake41 min
Sep 12, 3:02 PM MDTSevere Thunderstorm WarningSLCUtah38 min
Sep 12, 3:31 PM MDTSevere Thunderstorm WarningSLCSummit39 min
Sep 12, 3:34 PM MDTSevere Thunderstorm WarningSLCUtah41 min
Sep 12, 5:10 PM MDTTornado WarningSLCDavis, Weber35 min
Sep 12, 5:35 PM MDTSevere Thunderstorm WarningSLCBox Elder, Weber40 min

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.