Damaging Winds in South Dakota, May 28, 2017

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
155 PM MDT Sun May 28 2017

.DISCUSSION...(This Evening Through Sunday)
Issued at 153 PM MDT Sun May 28 2017

19z surface analysis had low over southern SK with trough into NE
and another into eastern MT. Upper low spinning over the southeast
SK with pinwheeling disturbances rotating around it into the
Dakotas. Upper/surface features tapping into 250-500J/kg MLCAPE to
produce another round of popcorn -TSRA this afternoon/evening.
Activity focused on Black Hills terrain and surface trough. A few
gusty storms will occur given 20-35kt 850mb winds. Activity will
end by 06z tonight as subsidence/drying takes hold. Temperatures
tonight will be tricky with dry air and clearing skies creating
widely varying readings.

Monday and Tuesday, modest upper ridge will bring a couple of nice
days. Little instability noted with general synoptic scale
subsidence supporting continued dry forecast. Temperatures will be
seasonal.

Wednesday through Sunday, split flow regime develops with
increasingly active northern branch of westerlies. PoPs will be
largely diurnal, except perhaps by next weekend when decent
cyclonic/northwest flow develops. Temperatures will be 5-10F above
normal on average.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1112 AM MDT Sun May 28 2017

Mainly VFR conditions are expected today. Some MVFR conditions
will be possible near showers and thunderstorms. A few storms may
be strong to severe. Northwest winds will be breezy this
afternoon, especially across northwestern SD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

DISCUSSION...Helgeson
AVIATION...15

Hazardous Weather Outlook
National Weather Service Rapid City SD
1046 AM MDT Sun May 28 2017

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-291300-
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-Northern Campbell-Southern Campbell-
Western Crook-Wyoming Black Hills-Weston-Northeastern Crook-
1046 AM MDT Sun May 28 2017 /1146 AM CDT Sun May 28 2017/

This Hazardous weather outlook is for western South Dakota and
Northeastern Wyoming.

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms will be possible this
afternoon and evening. There is a marginal risk of a few
thunderstorms becoming strong to severe, with hail being the main
concern with any storms.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Chances for thunderstorms will return Wednesday into next weekend.
Widespread severe storms are not anticipated at this time.

.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

Special Weather Statement
National Weather Service Rapid City SD
138 PM MDT SUN MAY 28 2017

SDZ027-029-030-041-074-282030-
Custer Co Plains SD-Fall River SD-Hermosa Foot Hills SD-
Southern Foot Hills SD-Southern Black Hills SD-
138 PM MDT SUN MAY 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL CUSTER AND
NORTHEASTERN FALL RIVER COUNTIES UNTIL 230 PM MDT...

At 137 PM MDT, Doppler radar was tracking a strong thunderstorm over
Wind Cave Visitors Center, or 8 miles north of Hot Springs, moving
southeast at 35 mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Hot Springs, Oral, Buffalo Gap, Smithwick, Wind Cave National Park,
Cottonwood Springs Dam, Wind Cave Visitors Center, Hay Canyon Butte,
Maverick Junction, Cold Brook Reservoir, Angostura Reservoir and
southeastern Custer State Park.

LAT...LON 4353 10363 4366 10334 4335 10301 4328 10301
      4314 10336
TIME...MOT...LOC 1937Z 325DEG 30KT 4354 10342

Rudge

Special Weather Statement
National Weather Service Rapid City SD
150 PM MDT SUN MAY 28 2017

SDZ002-282015-
Perkins SD-
150 PM MDT SUN MAY 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PERKINS COUNTY UNTIL
215 PM MDT...

At 150 PM MDT, Doppler radar was tracking a strong thunderstorm near
North Lemmon, or near Lemmon, moving southeast at 40 mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Lemmon.

LAT...LON 4574 10201 4594 10228 4595 10201 4594 10200
TIME...MOT...LOC 1950Z 313DEG 44KT 4599 10220

Rudge

Special Weather Statement
National Weather Service Rapid City SD
213 PM MDT SUN MAY 28 2017

SDZ041-042-282045-
Fall River SD-Oglala Lakota SD-
213 PM MDT SUN MAY 28 2017

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN OGLALA LAKOTA AND
SOUTHEASTERN FALL RIVER COUNTIES UNTIL 245 PM MDT...

At 213 PM MDT, Doppler radar was tracking a strong thunderstorm over
Hay Canyon Butte, or 18 miles southeast of Hot Springs, moving
southeast at 45 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Oelrichs, Hay Canyon Butte and Slim Butte.

LAT...LON 4324 10343 4330 10301 4300 10272 4300 10326
TIME...MOT...LOC 2013Z 319DEG 40KT 4323 10322

Rudge