Alert archive / South Dakota / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 49, NWS Rapid City, SD

May 21, 2004Haakon County, South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at May 21, 2004, 7:17 PM MDT for Haakon County, South Dakota. It was in force for 58 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
May 21, 2004, 7:17 PM MDT (01:17 UTC)
Expired
May 21, 2004, 8:15 PM MDT
In force
58 min
Issued by
NWS Rapid City, SD
Area
Counties, with a storm outline in the text

County Haakon County, SD

The radar

The Rapid City radar (KUDX), 105 km from the middle of the area, began a volume at 01:18 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

Aberdeen, SD (KABR), launched 00:00Z, 1.3 hours before the alert went out and 258 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, Aberdeen, SD at 00:00Z on 2004-05-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 49 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, Aberdeen, SD at 00:00Z on 2004-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
49 J/kg
Mixed-layer CIN
-159 J/kg
Mixed-layer LCL
1323 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at May 21, 1:30 PM MDT, 5 hours 47 minutes earlier.

Area forecast discussion, May 21, 1:30 PM MDT, 5 hours 47 minutes before
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
130 PM MDT FRI MAY 21 2004

.DISCUSSION...WATER VAPOR SHOWS UPR LOW OVR NV WITH NOSE OF
APPROACHING JET STREAK OVER ERN UT. SFC ANALYSIS PLACES SFC TROF OVR
THE FAR WRN DAKOTAS INTO FAR WRN NEB.  SFC HEATING HAS BROKEN CAP FM
THE BLACK HILLS WESTWARD PER LATEST LAPS ANALYSIS AND DEVELOPING CU
FIELD ON VISIBLE SATELLITE. CONVECTION ALREADY ENTERING FAR WRN
REACHES OF CWFA. FCST FOCUS REMAINS SVR WX THREAT REMAINDER OF THIS
AFTN AND EVE.

THRU TONIGHT...CONVECTION WILL CONT TO RAPIDLY FIRE THIS AFTN/EVE
ACRS NERN WY AND FAR WRN SD...AND GRADUALLY SPREAD/DEVELOP EWD THRU
THRU CNTRL SD THIS EVE. MLCAPES OF 2000-2500J/KG FM AND AMPLE SHEAR
FM THE BLACK HILLS EAST/SOUTHEASTWARD THRU SCNTRL SD WILL PROVIDE
BEST FOCUS FOR SUPERCELLS.  18Z KUNR SOUNDING SHOWS VERY STEEP MID
LVL LAPSE RATES. LARGE HAIL APPEARS TO BE MAIN THREAT
INITIALLY...WITH A BETTER CHC FOR STRONG WINDS AS THE ACTIVITY
PUSHES EWD INTO SCNTRL SD. LCLS SHOULD BE LOW ENOUGH FOR ISOLATED
TORNADOES ALG SFC TROF IN AREAS FM PINE RIDGE TO KADOKA TO
MARTIN...WHERE BEST LO LVL SHEAR WILL EXIST.

SAT...UPR LOW WILL DIVE SWD INTO THE PAC NW...EJECTING REMNANTS OF
UPR LOW CURRENTLY OVR NV ACRS THE CNTRL/NRN PLAINS. ANOTHER ROUND OF
TSTMS POSSIBLE...SOME AGAIN SVR ESPECIALLY DURG THE AFTN/EVE HOURS.

SUN-MON...UPR LOW OVR THE PAC NW WILL DRIFT SLOWLY EWD ACRS THE NRN
ROCKIES...KEEPING AREA UNDER MOIST SW FLOW ALOFT AND UNSETTLED
PATTERN. TEMPS WILL SLOWLY COOL DURG THIS PD AS THICKNESS VALUES
LOWER.

EXTENDED...LONGER RANGE GUIDANCE CONTS TO SHOW PATTERN SHIFT WITH
LONG WAVE TROF SHIFTING EAST OF REGION...PLACING REGION UNDER DRIER
W/NW FLOW ALOFT. THIS WILL ALLOW TEMPS TO WARM TO AOA AVERAGE VALUES.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
.SD...SEVERE TSTM WATCH UNTIL 700 PM MDT WESTERN SOUTH DAKOTA.
.WY...SEVERE TSTM WATCH UNTIL 700 PM MDT NORTHEASTERN SOUTH DAKOTA.

JOHNSON
Hazardous weather outlook, May 21, 9:30 AM MDT, 9 hours 47 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
930 AM MDT FRI MAY 21 2004

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-221300-
BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-
HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK-
NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS-
NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-
SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS-
SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-
WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH-
930 AM MDT (1030 AM CDT) FRI MAY 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND
NORTHEASTERN WYOMING.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEASTERN
WYOMING AND WESTERN THROUGH SOUTHERN SOUTH DAKOTA THIS AFTERNOON AND
EVENING.

LOW PRESSURE WILL DEVELOP ACROSS FAR SOUTHWESTERN SOUTH DAKOTA THIS
AFTERNOON...BRINGING MOIST AND UNSTABLE AIR INTO THE BLACK HILLS
REGION. THIS WILL HELP PRODUCE THUNDERSTORMS THIS AFTERNOON...
STARTING OVER AND NEAR THE BLACK HILLS...AND THEN SPREADING EASTWARD
ACROSS WEST CENTRAL AND SOUTHWESTERN SOUTH DAKOTA LATE THIS AFTERNOON
AND EVENING. THE MAIN THREAT FROM THE STORMS WILL BE LARGE HAIL THIS
AFTERNOON AND EARLY EVENING...ALTHOUGH THE THREAT OF DAMAGING WINDS
WILL INCREASE OVER SOUTH CENTRAL SOUTH DAKOTA AS THE EVENING
PROGRESSES. THERE IS ALSO A THREAT FOR ISOLATED TORNADOES BETWEEN
400 PM MDT AND 800 PM MDT...MAINLY SOUTHEAST OF THE BLACK HILLS FROM
PINE RIDGE TO KADOKA TO MARTIN. THE THREAT OF SEVERE WEATHER WILL
DIMINISH TOWARD MIDNIGHT AS THE MAIN AREA OF THUNDERSTORMS MOVES
INTO CENTRAL SOUTH DAKOTA.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THE CHANCE OF THUNDERSTORMS WILL CONTINUE FOR SATURDAY THROUGH
MONDAY. THERE IS A SLIGHT RISK OF SEVERE WEATHER SATURDAY AFTERNOON
AND EVENING ACROSS PORTIONS OF NORTHEASTERN WYOMING AND SOUTHWESTERN
SOUTH DAKOTA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY.

BUNKERS

In the hours before

Local storm report, May 21, 3:40 PM MDT, 3 hours 37 minutes before
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Local storm report, May 21, 3:45 PM MDT, 3 hours 32 minutes before
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Local storm report, May 21, 4:59 PM MDT, 2 hours 18 minutes before
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Local storm report, May 21, 5:01 PM MDT, 2 hours 16 minutes before
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Local storm report, May 21, 5:09 PM MDT, 2 hours 8 minutes before
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Special weather statement, May 21, 5:57 PM MDT, 1 hour 20 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
May 21, 6:13 PM MDTSevere Thunderstorm WarningUNRHaakon62 min
May 21, 6:40 PM MDTSevere Thunderstorm WarningUNRPennington35 min
May 22, 2:54 PM MDTSevere Thunderstorm WarningUNRPennington66 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2004Every severe thunderstorm warning in 2004

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.