Alert archive / South Dakota / Tornado Warnings in 1998

Tornado Warning 3, NWS Rapid City, SD

May 20, 1998Fall River County, South Dakota

NWS Rapid City, SD issued this tornado warning at May 20, 1998, 4:32 PM MDT for Fall River County, South Dakota. It was in force for 33 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: May 20, 1998, 4:32 PM MDT (22:32 UTC)
Expired: May 20, 1998, 5:05 PM MDT
In force: 33 min
Issued by: NWS Rapid City, SD
Area: Whole counties

County Fall River County, SD

The radar

The Rapid City radar (KUDX), 113 km from the middle of the area, began a volume at 22:32 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.

What was reported inside it

Time	Report	Where	Remark
May 20, 4:35 PM MDT	Hail 1	Hot Spgs, SD
May 20, 4:35 PM MDT	Tornado F0	Edgemont, SD

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 20, 1:30 PM MDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.5 hours before the alert went out and 375 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2106 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 110 m²/s²
0-3 km storm-relative helicity: 87 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.

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Rapid City, SD wrote its last area forecast discussion before this tornado warning went out at May 20, 10:05 AM MDT, 6 hours 27 minutes earlier.

Area forecast discussion, May 20, 10:05 AM MDT, 6 hours 27 minutes before

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD...CORRECTED DATE/TIME
1005 AM MDT WED MAY 20 1998

H20 VAP STLT LOOP SHOWS WHAT 12Z ETA SAYS IN THAT WK WAVE TO MOVE
THROUGH NE WY AND WRN SD MIDDAY AND THIS AFTERNOON. WOULD LOOK FOR A
LITTLE INTENSIFICATION OF -TSRA CURRENTLY OVR WRN WY...BUT UNSURE
ABOUT REDEVELOPMENT AFTER THIS BATCH OF SHOWERS PASS. CLD COVER
CURRENTLY SUPPRESSING HEATING OVR SD SO DEVELOPMENT WOULD HAVE TO
OCCUR IN THE NEXT FEW HOURS IN ERN WY...THEN MOVE INTO WRN SD. RUC2
SFC SHOWS AREA OF SFC H20 CONV IN ERN WY BY 00Z...ETA HAS THIS SAME
FEATURE A LITTLE SOONER THEN MOVES IT EAST INTO WRN SD. SO I GUESS
THAT MDLS MATCH UP WELL WITH CURRENT FCST AND I SHOULDNT NEED TO
UPDATE. ALSO ISSUED SPS FOR SLIGHT RISK OF SVR NE WY AND WRN SD AS
SHEAR AROUND 25 M/S AND CAPES A2500 SHOULD BE ENOUGH FOR A SUPERCELL
OR TWO.

.UNR...NONE.

BAILEY SPECI KUNR 201605Z 13012KT 17/13

The office that day

Everything else NWS Rapid City, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 20, 3:46 PM MDT	Severe Thunderstorm Warning	UNR	Fall River	49 min
May 20, 4:40 PM MDT	Severe Thunderstorm Warning	UNR	Pennington	35 min
May 20, 4:50 PM MDT	Severe Thunderstorm Warning	UNR	Custer	50 min
May 20, 4:59 PM MDT	Tornado Warning	UNR	Fall River	31 min
May 20, 5:23 PM MDT	Severe Thunderstorm Warning	UNR	Pennington	47 min
May 20, 5:26 PM MDT	Tornado Warning	UNR	Fall River	34 min
May 20, 5:56 PM MDT	Severe Thunderstorm Warning	UNR	Fall River	49 min
May 20, 2:49 PM MDT	Severe Thunderstorm Warning	UNR	Weston	46 min
May 20, 3:21 PM MDT	Tornado Warning	UNR	Weston	34 min
May 20, 3:21 PM MDT	Tornado Warning	UNR	Weston	29 min

Nearby

Tornado Warnings in South Dakota, 1998 Every tornado warning in 1998 Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.