Alert archive / Nebraska / Tornado Watches in 1998

Tornado Watch 379

May 20, 199812 counties in Nebraska; Custer County, Fall River County, South Dakota; 9 counties in Wyoming

The Storm Prediction Center issued this tornado watch at May 20, 1998, 1:30 PM MDT for 12 counties in Nebraska; Custer County, Fall River County, South Dakota; 9 counties in Wyoming. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 20, 1998, 1:30 PM MDT (19:30 UTC)
Expired
May 20, 1998, 7:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center
All 23 counties

Arthur County, NE, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Deuel County, NE, Garden County, NE, Keith County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Custer County, SD, Fall River County, SD, Campbell County, WY, Converse County, WY, Crook County, WY, Goshen County, WY, Johnson County, WY, Niobrara County, WY, Platte County, WY, Sheridan County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 153 km from the middle of the area, began a volume at 19:32 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.

Warnings issued inside it

18 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 20, 2:49 PM MDTSevere Thunderstorm WarningUNRWeston46 min
May 20, 3:21 PM MDTTornado WarningUNRWeston34 min
May 20, 3:21 PM MDTTornado WarningUNRWeston29 min
May 20, 3:31 PM MDTTornado WarningCYSNiobrara14 min
May 20, 3:46 PM MDTSevere Thunderstorm WarningUNRFall River49 min
May 20, 4:13 PM MDTSevere Thunderstorm WarningCYSSioux32 min
May 20, 4:32 PM MDTTornado WarningUNRFall River33 min
May 20, 4:46 PM MDTSevere Thunderstorm WarningCYSScotts Bluff34 min
May 20, 4:50 PM MDTSevere Thunderstorm WarningUNRCuster50 min
May 20, 4:59 PM MDTTornado WarningUNRFall River31 min
May 20, 5:26 PM MDTTornado WarningUNRFall River34 min
May 20, 5:28 PM MDTSevere Thunderstorm WarningCYSMorrill32 min
May 20, 5:56 PM MDTSevere Thunderstorm WarningUNRFall River49 min
May 20, 6:00 PM MDTTornado WarningUNRFall River35 min
May 20, 6:10 PM MDTSevere Thunderstorm WarningCYSMorrill30 min
May 20, 6:29 PM MDTTornado WarningCYSMorrill31 min
May 20, 6:46 PM MDTSevere Thunderstorm WarningUNRFall River34 min
May 20, 6:59 PM MDTTornado WarningCYSMorrill31 min

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 7.5 hours before the alert went out and 325 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, Riverton, WY at 12:00Z on 1998-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 1998-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 square meters per square second.1939587897Sfc1 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
2007 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
93 m²/s²
0-3 km storm-relative helicity
247 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 19, 6:00 PM MDTTornado WatchSPCArthur, Blaine, Brown, Cherry, Custer, Grant and 9 more5 hr
May 19, 9:00 PM MDTSevere Thunderstorm WatchSPCAdams, Antelope, Blaine, Boone, Brown, Buffalo and 41 more6 hr
May 20, 12:45 AM MDTSevere Thunderstorm WatchSPCBurt, Cass, Cuming, Dodge, Douglas, Gage and 10 more6 hr
May 20, 4:30 PM MDTTornado WatchSPCBlaine, Brown, Cherry, Grant, Hooker, Logan and 4 more7 hr

Nearby

Tornado Watches in Nebraska, 1998Tornado Watches in Wyoming, 1998Tornado Watches in South Dakota, 1998Every tornado watch 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.