Alert archive / South Dakota / Mesoscale Discussions in 2017

Mesoscale Discussion 982

June 10, 201723 counties in South Dakota; Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jun 10, 2017, 11:56 PM CDT for 23 counties in South Dakota; Weston County, Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 10, 2017, 11:56 PM CDT (04:56 UTC)
Expired: Jun 11, 2017, 2:00 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 24 counties

Brule County, SD, Buffalo County, SD, Butte County, SD, Custer County, SD, Dewey County, SD, Edmunds County, SD, Faulk County, SD, Haakon County, SD, Hand County, SD, Hughes County, SD, Hyde County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Lyman County, SD, Meade County, SD, Mellette County, SD, Pennington County, SD, Potter County, SD, Stanley County, SD, Sully County, SD, Walworth County, SD, Ziebach County, SD, Weston County, WY

The radar

The Rapid City radar (KUDX), 70 km from the middle of the area, began a volume at 04:56 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 (KRAP), launched 00:00Z, 4.9 hours before the alert went out and 76 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: 95 J/kg
Mixed-layer CIN: -46 J/kg
Mixed-layer LCL: 2486 m above ground
0-6 km bulk shear: 85 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

Open this sounding in Storm Lab

The text

As transmitted.

815 
ACUS11 KWNS 110457
SWOMCD
SPC MCD 110456 
SDZ000-WYZ000-110700-

Mesoscale Discussion 0982
NWS Storm Prediction Center Norman OK
1156 PM CDT Sat Jun 10 2017

Areas affected...Western and central SD

Concerning...Severe Thunderstorm Watch 310...

Valid 110456Z - 110700Z

The severe weather threat for Severe Thunderstorm Watch 310
continues.

SUMMARY...Thunderstorms with attendant severe-weather threat are
expected to increase in coverage from west to east overnight, with
large hail and damaging winds being the primary severe risks.

DISCUSSION...Mosaic radar imagery continued to show thunderstorms
developing across the western part of WW 310 (in northeast WY into
western SD), as strengthening southerly low-level winds result in
northward theta-e advection into southern SD.  This destabilizing
process will continue north of the warm front, which was analyzed at
0430Z extending from the NE Panhandle to northeast NE.  Objective
analyses indicated strong low-level warm air advection, especially
at 700 mb, which will further aid in destabilization.  Thus, these
factors combined with steepening midlevel lapse rates and increasing
bulk shear are expected to support additional thunderstorm
development from west to east, with a gradual increase in
severe-weather risk as activity develops from western into central
SD.  Last several runs of the HRRR suggest a marked increase in
thunderstorm coverage across WW 310 between 07-09Z.

..Peters.. 06/11/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FSD...ABR...UNR...

LAT...LON   43510302 43560468 44080493 44650397 45190343 45490227
            45660012 45589872 44219867 43429928 43360204 43510302

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 10, 9:44 PM CDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brule, Buffalo, Butte, Custer and 22 more	2 hr
Jun 10, 10:01 PM CDT	Severe Thunderstorm Watch	SPC	Buffalo, Butte, Custer, Dewey, Edmunds, Faulk and 17 more	7 hr
Jun 11, 2:02 AM CDT	Mesoscale Discussion	SPC	Beadle, Brookings, Buffalo, Clark, Codington, Day and 11 more	58 min
Jun 11, 2:37 AM CDT	Severe Thunderstorm Watch	SPC	Beadle, Brookings, Clark, Codington, Deuel, Grant and 8 more	5 hr
Jun 11, 4:00 AM CDT	Mesoscale Discussion	SPC	Beadle, Brookings, Jerauld, Kingsbury, Lake, Miner and 2 more	60 min
Jun 11, 3:49 PM CDT	Mesoscale Discussion	SPC	Albany, Laramie	2 hr

Nearby

Mesoscale Discussions in South Dakota, 2017 Mesoscale Discussions in Wyoming, 2017 Every mesoscale discussion in 2017

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.