Alert archive / South Dakota / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 227

June 27, 201823 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Jun 27, 2018, 12:12 AM CDT for 23 counties in South Dakota. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Jun 27, 2018, 12:12 AM CDT (05:12 UTC)
Expired
Jun 27, 2018, 9:00 AM CDT
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 23 counties

Buffalo County, SD, Butte County, SD, Campbell County, SD, Corson County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Harding County, SD, Hughes County, SD, Hyde County, SD, Jones County, SD, Lyman County, SD, McPherson County, SD, Meade County, SD, Pennington County, SD, Perkins County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD

The radar

The Rapid City radar (KUDX), 134 km from the middle of the area, began a volume at 05:13 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 27, 12:38 AM CDTSevere Thunderstorm WarningUNRHarding, Perkins67 min
Jun 27, 12:39 AM CDTSevere Thunderstorm WarningABRCorson51 min
Jun 27, 12:41 AM CDTSevere Thunderstorm WarningUNRPerkins, Ziebach64 min
Jun 27, 1:18 AM CDTSevere Thunderstorm WarningABRCorson, Dewey42 min
Jun 27, 1:20 AM CDTSevere Thunderstorm WarningUNRButte, Harding, Meade, Perkins55 min
Jun 27, 1:26 AM CDTSevere Thunderstorm WarningUNRMeade, Perkins, Ziebach64 min
Jun 27, 1:58 AM CDTSevere Thunderstorm WarningABRDewey47 min
Jun 27, 2:11 AM CDTSevere Thunderstorm WarningUNRMeade, Ziebach64 min
Jun 27, 2:23 AM CDTSevere Thunderstorm WarningUNRZiebach37 min
Jun 27, 2:42 AM CDTSevere Thunderstorm WarningABRDewey, Potter, Sully48 min
Jun 27, 3:05 AM CDTSevere Thunderstorm WarningUNRHaakon, Ziebach55 min
Jun 27, 3:28 AM CDTSevere Thunderstorm WarningABRDewey, Hughes, Stanley, Sully47 min
Jun 27, 4:12 AM CDTSevere Thunderstorm WarningUNRHaakon, Ziebach63 min
Jun 27, 4:13 AM CDTSevere Thunderstorm WarningABRBuffalo, Hughes, Hyde, Lyman47 min
Jun 27, 4:49 AM CDTSevere Thunderstorm WarningABRBuffalo, Hand, Hyde, Lyman26 min
Jun 27, 6:13 AM CDTSevere Thunderstorm WarningABRBuffalo, Lyman32 min
Jun 27, 6:16 AM CDTSevere Thunderstorm WarningABRHughes, Stanley29 min
Jun 27, 6:30 AM CDTSevere Thunderstorm WarningABRHughes, Lyman, Stanley30 min
Jun 27, 6:43 AM CDTSevere Thunderstorm WarningABRBuffalo, Lyman17 min
Jun 27, 6:50 AM CDTFlash Flood WarningABRHughes, Stanley3 hr
Jun 27, 6:53 AM CDTSevere Thunderstorm WarningABRHughes, Lyman, Stanley37 min
Jun 27, 7:25 AM CDTSevere Thunderstorm WarningABRBuffalo, Lyman50 min
Jun 27, 8:13 AM CDTSevere Thunderstorm WarningABRLyman17 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 00:00Z, 5.2 hours before the alert went out and 141 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 2018-06-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1573 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 2018-06-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
1573 J/kg
Mixed-layer CIN
-153 J/kg
Mixed-layer LCL
2012 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
202 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 26, 9:05 PM CDTMesoscale DiscussionSPCHarding, Perkins115 min
Jun 26, 11:52 PM CDTMesoscale DiscussionSPCBrule, Buffalo, Campbell, Corson, Dewey, Haakon and 15 more113 min
Jun 27, 2:18 AM CDTMesoscale DiscussionSPCBuffalo, Butte, Campbell, Corson, Dewey, Edmunds and 17 more87 min
Jun 27, 4:18 AM CDTMesoscale DiscussionSPCAurora, Brule, Buffalo, Charles Mix, Davison, Douglas and 10 more87 min
Jun 27, 4:34 AM CDTSevere Thunderstorm WatchSPCAurora, Beadle, Bon Homme, Brule, Charles Mix, Davison and 10 more5 hr
Jun 27, 7:25 AM CDTMesoscale DiscussionSPCAurora, Beadle, Bon Homme, Brule, Buffalo, Charles Mix and 18 more95 min

Nearby

Severe Thunderstorm Watches in South Dakota, 2018Every severe thunderstorm watch in 2018

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.