Alert archive / South Dakota / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 435

August 9, 20164 states

The Storm Prediction Center issued this severe thunderstorm watch at Aug 9, 2016, 4:16 PM MDT for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 9, 2016, 4:16 PM MDT (22:16 UTC)
Expired
Aug 9, 2016, 11:00 PM MDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
3.5 in
Strongest gust expected
70 kt
All 30 counties

Carter County, MT, Custer County, MT, Fallon County, MT, Powder River County, MT, Adams County, ND, Bowman County, ND, Grant County, ND, Hettinger County, ND, Sioux County, ND, Slope County, ND, Bennett County, SD, Butte County, SD, Corson County, SD, Custer County, SD, Dewey County, SD, Fall River County, SD, Haakon County, SD, Harding County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Stanley County, SD, Ziebach County, SD, Crook County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 139 km from the middle of the area, began a volume at 22:19 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

23 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 9, 4:58 PM MDTSevere Thunderstorm WarningBYZCarter, Powder River62 min
Aug 9, 5:02 PM MDTSevere Thunderstorm WarningUNRCuster, Pennington58 min
Aug 9, 5:36 PM MDTSevere Thunderstorm WarningUNRCuster, Pennington39 min
Aug 9, 5:53 PM MDTSevere Thunderstorm WarningBYZCarter52 min
Aug 9, 6:36 PM MDTSevere Thunderstorm WarningBISBowman, Slope54 min
Aug 9, 6:42 PM MDTTornado WarningBYZCarter63 min
Aug 9, 6:45 PM MDTSevere Thunderstorm WarningUNRHarding60 min
Aug 9, 7:31 PM MDTSevere Thunderstorm WarningUNRHarding29 min
Aug 9, 7:40 PM MDTSevere Thunderstorm WarningUNRHarding50 min
Aug 9, 7:46 PM MDTSevere Thunderstorm WarningBISAdams, Bowman59 min
Aug 9, 8:00 PM MDTSevere Thunderstorm WarningUNRHarding31 min
Aug 9, 8:17 PM MDTSevere Thunderstorm WarningUNRHarding, Perkins50 min
Aug 9, 8:39 PM MDTSevere Thunderstorm WarningBISAdams, Grant, Hettinger, Sioux66 min
Aug 9, 9:05 PM MDTSevere Thunderstorm WarningUNRPerkins70 min
Aug 9, 9:09 PM MDTSevere Thunderstorm WarningABRCorson51 min
Aug 9, 9:39 PM MDTSevere Thunderstorm WarningUNRPerkins, Ziebach51 min
Aug 9, 9:40 PM MDTSevere Thunderstorm WarningBISGrant, Sioux49 min
Aug 9, 9:43 PM MDTSevere Thunderstorm WarningBYZFallon25 min
Aug 9, 9:45 PM MDTSevere Thunderstorm WarningABRCorson, Dewey60 min
Aug 9, 10:24 PM MDTSevere Thunderstorm WarningUNRZiebach22 min
Aug 9, 10:43 PM MDTSevere Thunderstorm WarningBISBurleigh, Emmons, Grant, Kidder, Logan, Morton and 1 more62 min
Aug 9, 10:43 PM MDTSevere Thunderstorm WarningABRCampbell, Corson, Dewey, Walworth47 min
Aug 9, 11:00 PM MDTSevere Thunderstorm WarningABRCorson, Dewey45 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Rapid City, SD (KRAP), launched 12:00Z, 10.3 hours before the alert went out and 143 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 2016-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 813 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 12:00Z on 2016-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
813 J/kg
Mixed-layer CIN
-373 J/kg
Mixed-layer LCL
1614 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 2:19 PM MDTMesoscale DiscussionSPCBroadwater, Cascade, Chouteau, Deer Lodge, Granite, Jefferson and 8 more116 min
Aug 9, 3:51 PM MDTMesoscale DiscussionSPCCarter, Custer, Fallon, Powder River114 min
Aug 9, 4:53 PM MDTSevere Thunderstorm WatchSPCBlaine, Cascade, Chouteau, Fergus, Garfield, Glacier and 12 more7 hr
Aug 9, 5:35 PM MDTMesoscale DiscussionSPCBlaine, Broadwater, Cascade, Chouteau, Fergus, Garfield and 14 more85 min
Aug 8, 7:31 PM MDTMesoscale DiscussionSPCBenson, Cavalier, Eddy, Foster, Griggs, Nelson and 2 more89 min
Aug 8, 6:56 PM MDTMesoscale DiscussionSPCBennett, Haakon, Jackson, Jones, Meade, Mellette and 4 more94 min

Nearby

Severe Thunderstorm Watches in South Dakota, 2016Severe Thunderstorm Watches in North Dakota, 2016Severe Thunderstorm Watches in Montana, 2016Every severe thunderstorm watch in 2016

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.