Alert archive / South Dakota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 131, NWS Rapid City, SD

July 16, 20214 counties in South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at Jul 16, 2021, 6:20 PM MDT for 4 counties in South Dakota. It was in force for 55 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 16, 2021, 6:20 PM MDT (00:20 UTC)
Expired: Jul 16, 2021, 7:15 PM MDT
In force: 55 min
Issued by: NWS Rapid City, SD
Area: Storm-based polygon
Hail: 1.75 in
Wind: 60.0 mph

Counties Haakon County, SD, Jackson County, SD, Oglala Lakota County, SD, Pennington County, SD

The radar

The Rapid City radar (KUDX), 64 km from the middle of the area, began a volume at 00:21 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 watch it was issued in

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

Issued	Product	Office	Lasted
Jul 16, 3:55 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 0.3 hours before the alert went out and 65 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: 3551 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 73 m²/s²
0-3 km storm-relative helicity: 211 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 16, 5:14 PM MDT, 1 hour 6 minutes earlier.

Area forecast discussion, Jul 16, 5:14 PM MDT, 1 hour 6 minutes before

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
514 PM MDT Fri Jul 16 2021

.DISCUSSION...(This Evening Through Friday)
Issued at 228 PM MDT Fri Jul 16 2021

Current surface map has an area of lower pressure over eastern
Montana with a trough/dry line extending southward along the
Wyoming/South Dakota border. Upper level analysis has a shortwave
ridge of high pressure over the Rockies, with a few weak impulses
rounding the ridge as seen on water vapor imagery. Radar has a
couple of isolated storms over the northern Black Hills and Bear
Lodge Mountains. Temperatures range from the mid 80s over the
Black Hills into the 90s on the plains. Dew Points are in the 60s
ahead of the dryline/surface trough.

Steep lapse rates and moderate instability with 1000-1500 j/kg
MLCAPE will likely contribute to the development of additional storms
this afternoon as the cap weakens. Expect storms to continue to develop
this afternoon along the dryline and over the hills before
spreading southeast through the afternoon and evening. Effective
bulk shear of 30 to 35 kts should be sufficient for a few storms
to maintain updrafts, with strong winds and some hail being the
main threats from stronger storms. PWs are 75% of average today
across the hills, with higher PW values over south central South
Dakota. Storm motion is around 20 kts.

On Saturday, expect to see another impulse round the upper ridge in
the afternoon and evening. Initially, expect some high based
showers/storms form over the hills and along the lee trough in the
afternoon and evening. If any storms are able to make it off the
terrain, greater low level moisture east of the hills and modest
shear, may be able to support isolated/scattered organized storms on
the South Dakota plains. Isolated large hail and damaging winds
would be possible with any of these storms.

By Sunday, upper ridge builds with the upper high over the area,
resulting in mainly dry conditions and above average temperatures.
Highs will generally be in the 90s, possibly hitting 100 by the
middle of next week. The hot and dry conditions should hold for most
of the extended period, with only an isolated shower/storm over the
higher terrain during this time.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 513 PM MDT Fri Jul 16 2021

Thunderstorms will continue into the evening moving from the Black
Hills into southwestern and south central South Dakota. Some
storms will have strong winds and large hail.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

DISCUSSION...MLS
AVIATION...MLS

Hazardous weather outlook, Jul 16, 11:49 AM MDT, 6 hours 31 minutes before

Hazardous Weather Outlook...UPDATED
National Weather Service Rapid City SD
1149 AM MDT Fri Jul 16 2021

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-171300-
Harding-Perkins-Butte-Northern Meade Co Plains-Ziebach-
Northern Black Hills-Northern Foot Hills-Rapid City-
Southern Foot Hills-Central Black Hills-Southern Black Hills-
Custer Co Plains-Pennington Co Plains-Haakon-Fall River-
Oglala Lakota-Jackson-Bennett-Mellette-Todd-Tripp-
Sturgis/Piedmont Foot Hills-Southern Meade Co Plains-
Hermosa Foot Hills-
1149 AM MDT Fri Jul 16 2021 /1249 PM CDT Fri Jul 16 2021/

This Hazardous Weather Outlook is for western South Dakota.

.DAY ONE...This Afternoon and Tonight

Isolated to scattered thunderstorms are possible this afternoon
and evening. Some storms may become severe with damaging winds
and hail the primary hazards.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Scattered showers and thunderstorms are possible Saturday, but
severe storms are not anticipated at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

&&

Stay tuned to NOAA weather radio for further updates...or check
our web site at weather.gov/rapidcity

WYZ054>058-071-171300-
Northern Campbell-Southern Campbell-Western Crook-
Wyoming Black Hills-Weston-Northeastern Crook-
1149 AM MDT Fri Jul 16 2021

This Hazardous Weather Outlook is for northeastern Wyoming.

.DAY ONE...This Afternoon and Tonight

Isolated showers and thunderstorms are possible this afternoon and
evening, but storms are not expected to become severe.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Scattered showers and thunderstorms are possible Saturday
afternoon and evening, but severe storms are not anticipated at
this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today.

&&

Stay tuned to NOAA weather radio for further updates...or check
our web site at weather.gov/rapidcity

In the hours before

Local storm report, Jul 16, 5:29 PM MDT, 51 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE RAPID CITY SD
529 PM MDT FRI JUL 16 2021

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

0513 PM     HAIL             5 NNW FAIRBURN          43.75N 103.24W
07/16/2021  M2.00 INCH       CUSTER             SD   TRAINED SPOTTER

            HAIL RANGED FROM PEA SIZE UP TO 2 INCH IN DIAMETER.
            HAILED FROM 513 PM TO 519 PM. HALF INCH OF RAIN.

&&

CORRECTED REMARKS

MLS

Local storm report, Jul 16, 5:50 PM MDT, 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
550 PM MDT FRI JUL 16 2021

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

0533 PM     TSTM WND GST     1 E DWTN RAPID CITY     44.07N 103.21W
07/16/2021  M51 MPH          PENNINGTON         SD   OFFICIAL NWS OBS

&&

WFO UNR

Local storm report, Jul 16, 5:54 PM MDT, 26 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
554 PM MDT FRI JUL 16 2021

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

0545 PM     TSTM WND GST     5 N SCENIC              43.86N 102.54W
07/16/2021  E60 MPH          PENNINGTON         SD   TRAINED SPOTTER

&&

MLS

Special weather statement, Jul 16, 5:58 PM MDT, 22 minutes before

Special Weather Statement
National Weather Service Rapid City SD
558 PM MDT Fri Jul 16 2021

SDZ031-032-043-073-170045-
Jackson SD-Pennington Co Plains SD-Southern Meade Co Plains SD-
Haakon SD-
558 PM MDT Fri Jul 16 2021

...STRONG THUNDERSTORMS OVER SOUTHWESTERN HAAKON...SOUTHEASTERN
MEADE...NORTHWESTERN JACKSON AND SOUTHEASTERN PENNINGTON COUNTIES...

At 556 PM MDT, Doppler radar was tracking strong outflow winds along
a line extending from 8 miles northeast of Wasta to 4 miles east of
Badlands National Park. Movement was east at 40 mph.

Wind gusts of 50 to 55 mph will be possible with these storms.

Locations impacted include...
Wall, Interior, Quinn, Grindstone, Cactus Flat, Cedar Pass,
Cottonwood, Delta 9 Missile Silo, Minuteman Missile Visitors Center,
Pinnacles Ranger Station, Grindstone Butte, Delta 1 Launch Facility
and northeastern Badlands National Park.

This includes Interstate 90 in South Dakota between Mile Markers 100
and 140.

A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
southwestern and west central South Dakota.

LAT...LON 4370 10214 4370 10215 4369 10218 4369 10248
      4423 10240 4421 10170 4368 10171 4366 10214
TIME...MOT...LOC 2356Z 274DEG 36KT 4416 10233 4371 10239

Johnson

Local storm report, Jul 16, 6:10 PM MDT, 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
610 PM MDT FRI JUL 16 2021

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

0554 PM     TSTM WND GST     3 NNW SCENIC            43.82N 102.58W
07/16/2021  M51 MPH          PENNINGTON         SD   MESONET

0556 PM     TSTM WND GST     17 WSW WRIGHT           43.62N 105.79W
07/16/2021  M53 MPH          CAMPBELL           WY   MESONET

0604 PM     TSTM WND GST     3 NW WASTA              44.10N 102.50W
07/16/2021  M56 MPH          PENNINGTON         SD   MESONET

&&

MLS

Local storm report, Jul 16, 6:17 PM MDT, 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
617 PM MDT FRI JUL 16 2021

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

0605 PM     TSTM WND GST     3 NNW SCENIC            43.82N 102.58W
07/16/2021  M55 MPH          PENNINGTON         SD   MESONET

0609 PM     TSTM WND GST     3 NW WASTA              44.10N 102.50W
07/16/2021  M58 MPH          PENNINGTON         SD   MESONET

&&

WFO UNR

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 6:10 PM MDT	Severe Thunderstorm Warning	UNR	Bennett, Jackson, Oglala Lakota	65 min
Jul 16, 6:56 PM MDT	Flash Flood Warning	UNR	Oglala Lakota	6 hr
Jul 16, 7:12 PM MDT	Severe Thunderstorm Warning	UNR	Bennett, Oglala Lakota	48 min
Jul 16, 7:18 PM MDT	Severe Thunderstorm Warning	UNR	Haakon, Jackson, Mellette	57 min
Jul 16, 8:19 PM MDT	Special Weather Statement	UNR	Mellette, Todd	41 min
Jul 16, 9:02 PM MDT	Special Weather Statement	UNR	Todd	43 min
Jul 16, 9:05 PM MDT	Special Weather Statement	UNR		40 min
Jul 17, 2:14 PM MDT	Special Weather Statement	UNR	Lawrence	46 min
Jul 17, 3:06 PM MDT	Special Weather Statement	UNR	Lawrence	39 min
Jul 17, 4:05 PM MDT	Special Weather Statement	UNR	Lawrence	40 min
Jul 17, 4:40 PM MDT	Special Weather Statement	UNR	Custer	50 min
Jul 17, 5:25 PM MDT	Special Weather Statement	UNR	Custer	35 min
Jul 17, 5:34 PM MDT	Severe Thunderstorm Warning	UNR	Custer, Fall River	41 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2021 Every severe thunderstorm warning in 2021

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.