Alert archive / South Dakota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 107, NWS Rapid City, SD

July 9, 2021Mellette County, Todd County, South Dakota

NWS Rapid City, SD issued this severe thunderstorm warning at Jul 9, 2021, 12:20 AM CDT for Mellette County, Todd County, South Dakota. It was in force for 40 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 9, 2021, 12:20 AM CDT (05:20 UTC)
Expired
Jul 9, 2021, 1:00 AM CDT
In force
40 min
Issued by
NWS Rapid City, SD
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

Counties Mellette County, SD, Todd County, SD

The radar

The North Platte radar (KLNX), 159 km from the middle of the area, began a volume at 05:23 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, 5.3 hours before the alert went out and 188 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 00:00Z on 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1357 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, Rapid City, SD at 00:00Z on 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 111 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
1357 J/kg
Mixed-layer CIN
-133 J/kg
Mixed-layer LCL
2075 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
111 m²/s²
0-3 km storm-relative helicity
272 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.3

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 9, 12:17 AM CDT, 3 minutes earlier.

Area forecast discussion, Jul 9, 12:17 AM CDT, 3 minutes before
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Hazardous weather outlook, Jul 8, 6:41 AM CDT, 17 hours 39 minutes before
Hazardous Weather Outlook
National Weather Service Rapid City SD
541 AM MDT Thu Jul 8 2021

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ056-057-
071-091300-
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-Western Crook-Wyoming Black Hills-
Northeastern Crook-
541 AM MDT Thu Jul 8 2021 /641 AM CDT Thu Jul 8 2021/

This Hazardous Weather Outlook is for portions of western South
Dakota and northeastern Wyoming.

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms will be possible this
afternoon and evening, mainly from northwestern through south
central SD. Although coverage will be limited, any storm that
develops will be capable of producing very large hail and damaging
winds. Chances are low, but a tornado cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Additional rounds of thunderstorms will be possible Friday and
Saturday. A few strong to severe storms may develop again on
Friday, particularly along and south of the I-90 corridor.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed today.

&&

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

WYZ055-058-091300-
Southern Campbell-Weston-
541 AM MDT Thu Jul 8 2021

This Hazardous Weather Outlook is for portions of northeast
Wyoming.

.DAY ONE...Today and Tonight

Critical fire weather conditions are expected from late this
morning through early this evening. See the RFWUNR product for
more information.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Thunderstorms will be possible Friday and Saturday. A few strong
to severe storms may develop on Friday.

.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

WYZ054-091300-
Northern Campbell-
541 AM MDT Thu Jul 8 2021

This Hazardous Weather Outlook is for portions of northeast
Wyoming.

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Thunderstorms will be possible Friday and Saturday. A few strong
to severe storms may develop on Friday.

.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 8, 9:08 PM CDT, 3 hours 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
808 PM MDT THU JUL 08 2021

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

0755 PM     HAIL             6 W MARTIN              43.17N 101.85W
07/08/2021  M1.50 INCH       BENNETT            SD   EMERGENCY MNGR

            MOSTLY SMALL HAIL...BUT A FEW PING PONG BALLS

&&

EAGAN
Special weather statement, Jul 8, 9:11 PM CDT, 3 hours 9 minutes before
Special Weather Statement
National Weather Service Rapid City SD
811 PM MDT Thu Jul 8 2021

SDZ044-090245-
Bennett SD-
811 PM MDT Thu Jul 8 2021

...STRONG THUNDERSTORM OVER SOUTH CENTRAL BENNETT COUNTY...

At 810 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles south of Sunrise Housing, or 6 miles south of Martin, moving
southeast at 40 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Sunrise Housing and Lacreek Wildlife Refuge.

A Severe Thunderstorm Watch remains in effect until 1000 PM MDT for
southwestern South Dakota.

LAT...LON 4307 10184 4314 10177 4319 10167 4300 10144
      4300 10181
TIME...MOT...LOC 0210Z 323DEG 35KT 4307 10174

Eagan
Local storm report, Jul 8, 9:43 PM CDT, 2 hours 37 minutes before
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Local storm report, Jul 8, 9:56 PM CDT, 2 hours 24 minutes before
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Local storm report, Jul 8, 10:22 PM CDT, 1 hour 58 minutes before
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Local storm report, Jul 8, 10:57 PM CDT, 1 hour 23 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 8, 7:14 PM CDTSevere Thunderstorm WarningUNRCuster, Jackson, Oglala Lakota, Pennington61 min
Jul 8, 7:39 PM CDTSevere Thunderstorm WarningUNRHarding, Perkins66 min
Jul 8, 7:58 PM CDTSevere Thunderstorm WarningUNRPerkins, Ziebach47 min
Jul 8, 8:10 PM CDTSevere Thunderstorm WarningUNRBennett, Jackson, Oglala Lakota65 min
Jul 8, 8:42 PM CDTSevere Thunderstorm WarningUNRPerkins, Ziebach63 min
Jul 8, 8:43 PM CDTSevere Thunderstorm WarningUNRPerkins62 min
Jul 8, 9:11 PM CDTSpecial Weather StatementUNRBennett34 min
Jul 8, 9:32 PM CDTSevere Thunderstorm WarningUNRHaakon, Ziebach58 min
Jul 8, 9:34 PM CDTSevere Thunderstorm WarningUNRMeade, Perkins, Ziebach56 min
Jul 8, 10:28 PM CDTSevere Thunderstorm WarningUNRHaakon, Meade, Ziebach62 min
Jul 8, 10:30 PM CDTSevere Thunderstorm WarningUNRHaakon, Ziebach24 min
Jul 8, 11:25 PM CDTSevere Thunderstorm WarningUNRHaakon, Jackson, Mellette65 min
Jul 9, 12:56 AM CDTSpecial Weather StatementUNRTripp49 min
Jul 9, 4:41 PM CDTSpecial Weather StatementUNRCuster34 min
Jul 9, 4:57 PM CDTSevere Thunderstorm WarningUNRLawrence, Meade, Pennington12 min
Jul 9, 5:10 PM CDTSpecial Weather StatementUNRCuster35 min
Jul 9, 5:30 PM CDTSpecial Weather StatementUNRCuster15 min
Jul 9, 5:47 PM CDTSpecial Weather StatementUNRCuster28 min
Jul 9, 6:28 PM CDTSpecial Weather StatementUNRCuster32 min
Jul 9, 6:41 PM CDTSevere Thunderstorm WarningUNRCuster, Fall River, Oglala Lakota28 min
Jul 9, 6:27 PM CDTSevere Thunderstorm WarningUNRCampbell, Crook63 min

Nearby

Severe Thunderstorm Warnings in South Dakota, 2021Every 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.