Alert archive / South Dakota / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 228

June 27, 201816 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Jun 27, 2018, 4:34 AM CDT for 16 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jun 27, 2018, 4:34 AM CDT (09:34 UTC)
Expired
Jun 27, 2018, 10:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt

Counties Aurora County, SD, Beadle County, SD, Bon Homme County, SD, Brule County, SD, Charles Mix County, SD, Davison County, SD, Douglas County, SD, Gregory County, SD, Hanson County, SD, Hutchinson County, SD, Jerauld County, SD, McCook County, SD, Miner County, SD, Sanborn County, SD, Turner County, SD, Yankton County, SD

The radar

The Sioux Falls radar (KFSD), 105 km from the middle of the area, began a volume at 09:35 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
5%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
10%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 27, 5:10 AM CDTSevere Thunderstorm WarningFSDAurora, Brule, Jerauld35 min
Jun 27, 5:45 AM CDTSevere Thunderstorm WarningFSDAurora, Brule45 min
Jun 27, 6:25 AM CDTSevere Thunderstorm WarningFSDAurora, Brule, Charles Mix, Davison, Douglas35 min
Jun 27, 6:46 AM CDTSevere Thunderstorm WarningFSDBrule44 min
Jun 27, 6:55 AM CDTSevere Thunderstorm WarningFSDAurora, Davison, Douglas, Hutchinson35 min
Jun 27, 7:22 AM CDTSevere Thunderstorm WarningFSDBon Homme, Hutchinson, Yankton38 min
Jun 27, 7:29 AM CDTSevere Thunderstorm WarningFSDAurora, Brule24 min
Jun 27, 7:57 AM CDTSevere Thunderstorm WarningFSDBon Homme, Hutchinson, Yankton19 min
Jun 27, 8:06 AM CDTSevere Thunderstorm WarningFSDBrule39 min
Jun 27, 8:42 AM CDTSevere Thunderstorm WarningFSDAurora, Brule, Charles Mix48 min
Jun 27, 9:22 AM CDTSevere Thunderstorm WarningFSDAurora, Brule, Charles Mix, Douglas38 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

Aberdeen, SD (KABR), launched 00:00Z, 9.6 hours before the alert went out and 130 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, Aberdeen, SD at 00:00Z on 2018-06-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 39 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, Aberdeen, SD at 00:00Z on 2018-06-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.193958Sfc1 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
39 J/kg
Mixed-layer CIN
-213 J/kg
Mixed-layer LCL
1431 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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, 12:12 AM CDTSevere Thunderstorm WatchSPCBuffalo, Butte, Campbell, Corson, Dewey, Edmunds and 17 more9 hr
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, 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.