Alert archive / South Dakota / Tornado Warnings in 1999

Tornado Warning 9, NWS Rapid City, SD

May 21, 1999Pennington County, South Dakota

NWS Rapid City, SD issued this tornado warning at May 21, 1999, 5:34 PM MDT for Pennington County, South Dakota. It was in force for 36 min. 1 report 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 21, 1999, 5:34 PM MDT (23:34 UTC)
Expired
May 21, 1999, 6:10 PM MDT
In force
36 min
Issued by
NWS Rapid City, SD
Area
Whole counties

County Pennington County, SD

What was reported inside it

TimeReportWhereRemark
May 21, 5:45 PM MDTHail 0.75Hill City, 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.

IssuedProductOfficeLasted
May 21, 2:00 PM MDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 11.6 hours before the alert went out and 9 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, Rapid City, SD at 12:00Z on 1999-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Rapid City, SD at 12:00Z on 1999-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -39 square meters per square second.19395878Sfc1 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
1886 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-39 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

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

The office that day

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

IssuedProductOfficeCountiesLasted
May 21, 1:53 PM MDTSevere Thunderstorm WarningUNRMeade47 min
May 21, 2:36 PM MDTSevere Thunderstorm WarningUNRMeade29 min
May 21, 3:03 PM MDTSevere Thunderstorm WarningUNRHarding62 min
May 21, 3:07 PM MDTSevere Thunderstorm WarningUNRMeade63 min
May 21, 3:19 PM MDTSevere Thunderstorm WarningUNRPennington46 min
May 21, 4:04 PM MDTSevere Thunderstorm WarningUNRMeade, Pennington61 min
May 21, 4:12 PM MDTTornado WarningUNRMeade, Pennington28 min
May 21, 4:22 PM MDTSevere Thunderstorm WarningUNRHarding48 min
May 21, 4:43 PM MDTSevere Thunderstorm WarningUNRCuster62 min
May 21, 5:07 PM MDTSevere Thunderstorm WarningUNRPennington63 min
May 21, 5:11 PM MDTSevere Thunderstorm WarningUNRButte, Perkins64 min
May 21, 5:19 PM MDTSevere Thunderstorm WarningUNRPennington66 min
May 21, 5:46 PM MDTSevere Thunderstorm WarningUNRCuster64 min
May 21, 5:51 PM MDTTornado WarningUNRFall River34 min
May 21, 3:34 PM MDTSevere Thunderstorm WarningUNRCrook46 min
May 21, 4:19 PM MDTSevere Thunderstorm WarningUNRWeston46 min
May 21, 4:54 PM MDTSevere Thunderstorm WarningUNRWeston46 min

Nearby

Tornado Warnings in South Dakota, 1999Every tornado warning in 1999Tornadoes in 1999

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.