Alert archive / South Dakota / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 170, NWS Rapid City, SD

July 20, 2012Haakon County, South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at Jul 20, 2012, 9:56 PM MDT for Haakon County, South Dakota. It was in force for 64 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 20, 2012, 9:56 PM MDT (03:56 UTC)
Expired: Jul 20, 2012, 11:00 PM MDT
In force: 64 min
Issued by: NWS Rapid City, SD
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Haakon County, SD

The radar

The Rapid City radar (KUDX), 105 km from the middle of the area, began a volume at 03:55 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

Rapid City, SD (KUNR), launched 00:00Z, 3.9 hours before the alert went out and 110 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: 3532 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 73 m²/s²
0-3 km storm-relative helicity: 329 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 Jul 20, 9:10 PM MDT, 46 minutes earlier.

Area forecast discussion, Jul 20, 9:10 PM MDT, 46 minutes before

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Hazardous weather outlook, Jul 20, 2:30 PM MDT, 7 hours 26 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
230 PM MDT FRI JUL 20 2012

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-211300-
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-
230 PM MDT (330 PM CDT) FRI JUL 20 2012

...HEAT ADVISORY THROUGH MIDNIGHT TONIGHT FOR WESTERN SOUTH
DAKOTA PLAINS...
...HEAT ADVISORY THROUGH MIDNIGHT SATURDAY NIGHT FOR SOUTH CENTRAL
SOUTH DAKOTA...

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER NORTHEAST WYOMING AND
FAR WESTERN SOUTH DAKOTA THIS AFTERNOON...SPREADING EAST OVERNIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER FAR
NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH DAKOTA. DAMAGING WINDS
AND LARGE HAIL WILL BE THE MAIN THREAT.

HOT WEATHER WILL CONTINUE THIS AFTERNOON...WITH HEAT INDEX READINGS
OF 100 TO 110 DEGREES OVER PORTIONS OF THE SOUTH DAKOTA PLAINS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A STRONG UPPER LEVEL RIDGE WILL CONTINUE TO BRING HOT WEATHER
THROUGH EARLY NEXT WEEK. HEAT INDICES WILL PEAK FROM 100 TO 105
DEGREES OVER SOUTH CENTRAL SOUTH DAKOTA SATURDAY.

THUNDERSTORMS ARE POSSIBLE THROUGH EARLY NEXT WEEK. SOME
THUNDERSTORMS MAY BE SEVERE WITH THE MAIN THREAT BEING DAMAGING
WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE THIS AFTERNOON AND TONIGHT.

In the hours before

Special weather statement, Jul 20, 4:35 PM MDT, 5 hours 21 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
435 PM MDT FRI JUL 20 2012

SDZ027>029-041-WYZ057-058-202330-
CENTRAL BLACK HILLS SD-FALL RIVER SD-SOUTHERN BLACK HILLS SD-SOUTHERN
FOOT HILLS SD-WESTON WY-WYOMING BLACK HILLS WY-
435 PM MDT FRI JUL 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR EXTREME SOUTHEASTERN CROOK...
EASTERN WESTON...NORTHWESTERN FALL RIVER...WESTERN CUSTER AND WESTERN
PENNINGTON COUNTIES UNTIL 530 PM MDT...

AT 433 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 8 MILES SOUTHWEST OF
OSAGE TO 10 MILES WEST OF EDGEMONT...AND MOVING NORTHEAST AT 25 MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH
FREQUENT DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE...
  EDGEMONT...
  DOWNTOWN NEWCASTLE...
  DOWNTOWN HOT SPRINGS...
  OSAGE...
  DEWEY...
  FOUR CORNERS...
  JEWEL CAVE...
  MOON...
  ARGYLE...
  COTTONWOOD SPRINGS DAM...
  BUCKHORN...
  PRINGLE...
  COLD BROOK RESERVOIR...
  MAVERICK JUNCTION...

THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS... FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 4349 10406 4350 10432 4396 10471 4422 10406
      4414 10406 4414 10394 4338 10337 4319 10406
TIME...MOT...LOC 2235Z 240DEG 21KT 4392 10454 4332 10402

HELGESON

Local storm report, Jul 20, 4:46 PM MDT, 5 hours 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
446 PM MDT FRI JUL 20 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0430 PM     TSTM WND GST     8 ESE NORRIS            43.42N 101.05W
07/20/2012  E60 MPH          MELLETTE           SD   PUBLIC

&&

ME

Special weather statement, Jul 20, 5:10 PM MDT, 4 hours 46 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
510 PM MDT FRI JUL 20 2012

SDZ024-027>029-041-WYZ056>058-210000-
CENTRAL BLACK HILLS SD-FALL RIVER SD-NORTHERN BLACK HILLS SD-SOUTHERN
BLACK HILLS SD-SOUTHERN FOOT HILLS SD-WESTERN CROOK WY-WESTON
WY-WYOMING BLACK HILLS WY-
510 PM MDT FRI JUL 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN CROOK...EASTERN
WESTON...NORTHWESTERN FALL RIVER...WESTERN CUSTER...SOUTHWESTERN
LAWRENCE AND WESTERN PENNINGTON COUNTIES UNTIL 600 PM MDT...

AT 506 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 7 MILES WEST OF
SUNDANCE TO MOON TO 7 MILES NORTHWEST OF EDGEMONT...AND MOVING
NORTHEAST AT 30 MPH.

WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH
FREQUENT DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE...
  SUNDANCE...
  DOWNTOWN CUSTER...
  HILL CITY...
  MOON...
  FOUR CORNERS...
  WARREN PEAK...
  BUCKHORN...
  JEWEL CAVE...
  MOSKEE...
  DEERFIELD...
  O'NEIL PASS...
  DEERFIELD RESERVOIR...
  ARGYLE...
  CRAZY HORSE MEMORIAL...
  SANATOR...
  ROCHFORD...
  PRINGLE...
  MYSTIC...
  CHEYENNE CROSSING...
  SYLVAN LAKE...
  MYRTLE FIRE AREA...

THIS INCLUDES INTERSTATE 90 BETWEEN WYOMING MILE MARKERS 173 AND
203...

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

&&

LAT...LON 4334 10407 4349 10406 4349 10417 4378 10435
      4441 10466 4462 10422 4412 10357 4346 10351
      4324 10400
TIME...MOT...LOC 2309Z 236DEG 28KT 4439 10448 4389 10398
          4338 10391

HELGESON

Special weather statement, Jul 20, 6:26 PM MDT, 3 hours 30 minutes before

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Special weather statement, Jul 20, 9:24 PM MDT, 32 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
924 PM MDT FRI JUL 20 2012

SDZ014-032-210415-
HAAKON SD-ZIEBACH SD-
924 PM MDT FRI JUL 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN ZIEBACH AND NORTHERN
HAAKON COUNTIES UNTIL 1015 PM MDT...

AT 923 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 11 MILES SOUTHWEST
OF SOUTH EAGLE BUTTE TO 6 MILES SOUTHWEST OF BILLSBURG...AND MOVING
EAST AT 40 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THESE STORMS...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

THESE STORMS WILL BE NEAR...
KIRLEY AROUND 945 PM MDT.
OTTUMWA AROUND 950 PM MDT.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

&&

LAT...LON 4470 10112 4468 10114 4434 10114 4418 10116
      4428 10197 4492 10136 4493 10113
TIME...MOT...LOC 0324Z 264DEG 39KT 4485 10130 4436 10177

RICHARDS

Special weather statement, Jul 20, 9:46 PM MDT, 10 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
946 PM MDT FRI JUL 20 2012

SDZ014-032-210430-
HAAKON SD-ZIEBACH SD-
946 PM MDT FRI JUL 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN ZIEBACH AND EASTERN
HAAKON COUNTIES UNTIL 1030 PM MDT...

AT 941 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 14 MILES SOUTH OF
SOUTH EAGLE BUTTE TO BILLSBURG TO 12 MILES NORTH OF PHILIP TO 5 MILES
SOUTHEAST OF PHILIP...AND MOVING EAST AT 35 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THESE STORMS...ALONG WITH FREQUENT DANGEROUS LIGHTNING.

THESE STORMS WILL BE NEAR...
KIRLEY AROUND 1000 PM MDT.
OTTUMWA AROUND 1025 PM MDT.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

&&

LAT...LON 4400 10164 4425 10173 4445 10171 4491 10120
      4487 10113 4418 10116 4416 10103 4401 10104
TIME...MOT...LOC 0346Z 306DEG 19KT 4478 10116 4439 10160
          4420 10162 4400 10154

RICHARDS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 6:26 PM MDT	Special Weather Statement	UNR	Custer	49 min
Jul 20, 9:01 PM MDT	Heat Advisory	UNR	Bennett, Mellette, Todd, Tripp	22 hr
Jul 20, 9:24 PM MDT	Special Weather Statement	UNR	Haakon	51 min
Jul 20, 9:46 PM MDT	Special Weather Statement	UNR	Haakon	44 min
Jul 21, 12:57 PM MDT	Special Weather Statement	UNR	Lawrence	48 min
Jul 21, 2:03 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Meade	42 min
Jul 21, 2:37 PM MDT	Special Weather Statement	UNR	Pennington	38 min
Jul 21, 3:32 PM MDT	Severe Thunderstorm Warning	UNR	Meade	31 min
Jul 21, 4:26 PM MDT	Severe Thunderstorm Warning	UNR	Custer, Pennington	64 min
Jul 21, 5:23 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence	67 min
Jul 21, 5:29 PM MDT	Severe Thunderstorm Warning	UNR	Custer, Pennington	10 min
Jul 21, 5:40 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Pennington	65 min
Jul 21, 5:53 PM MDT	Special Weather Statement	UNR	Harding	52 min
Jul 21, 5:55 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Pennington	18 min
Jul 21, 5:59 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Meade	40 min
Jul 21, 5:45 PM MDT	Severe Thunderstorm Warning	UNR	Crook	42 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2012 Every severe thunderstorm warning in 2012

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.