Alert archive / Utah / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 50, NWS Salt Lake City, UT

July 21, 1998San Juan County, Utah

NWS Salt Lake City, UT issued this severe thunderstorm warning at Jul 21, 1998, 2:15 PM MDT for San Juan County, Utah. It was in force for 45 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
Jul 21, 1998, 2:15 PM MDT (20:15 UTC)
Expired
Jul 21, 1998, 3:00 PM MDT
In force
45 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 20:14 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, 8.3 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 1998-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 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 1998-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -14 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3036 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-14 m²/s²
0-3 km storm-relative helicity
21 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.

747 
WUUS1 KSLC 212019 RRA
SVRSLC
UTC037-212100-

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

THE NATIONAL WEATHER SERVICE IN SALT LAKE CITY HAS ISSUED A

   * SEVERE THUNDERSTORM WARNING FOR...
     CENTRAL SAN JUAN COUNTY IN UTAH

   * UNTIL 300 PM MDT

   * AT 207 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
     SEVERE THUNDERSTORM ABOUT 11 MILES WEST OF MONTICELLO...MOVING  
     SOUTHEAST AT 5 MILES PER HOUR.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG
BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...LOCAL FLASH 
FLOODING...AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE 
THUNDERSTORMS. STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS 
PASSED.

LAT...LON 3788 10969 3762 10960 3776 10930 3797 10948

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, 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
Jul 21, 5:41 PM MDTFlash Flood WarningSLCWashington3 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.