Special Weather Statement, NWS Rapid City, SD

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
524 AM MDT Mon Aug 6 2018

.DISCUSSION...(Today Through Sunday)
Issued at 252 AM MDT Mon Aug 6 2018

Current surface analysis shows frontal boundary now well south
and east of the area, with high pressure over the Northern
Rockies. Another frontal boundary lies north of the area across
northeast MT, ND, and northern MN. Upper level analysis shows near
zonal flow over the region at the moment, with a shortwave noted
over eastern MT into south central Canada. A few showers linger
early this morning over northwest SD, with mostly clear skies
elsewhere. Temps are in the 50s and lower 60s across much of the
area with light winds.

One more unsettled day is on tap for much of the area as the
shortwave to the northwest slides southeast through much of the
Northern Plains today. Showers and thunderstorms will increase in
coverage, especially by early afternoon. The threat for severe
storms should be rather low as shear will be relatively weak and
forecast instability will be less than recent days, MUCAPE mostly in
the 500 to 1000 j/kg range. The best chance for a stronger storm or
two will likely be across southwest SD in closer vicinity to better
instability expected across the Nebraska panhandle. Showers and
thunderstorms will be scattered about from the Black Hills area
north and eastward this afternoon into the early evening, likely
more numerous over the Black Hills. Highs will generally be in the
mid 70s to mid 80s, 70s over the Black Hills. Pcpn will shift east
and gradually dissipate this evening, exiting east of the area
around midnight. Lows tonight will mostly be in the 50s.

For Tuesday and beyond, a much drier and eventually hot pattern will
develop across the Northern Plains. A strong ridge will build over
the western US early this week and eventually shift east into the
plains late in the week. Would not totally rule out a shower or
thundershower over the Black Hills or points to the south and west
late Tuesday, but the chances look too low now to include in the
forecast. Will keep the dry forecast going for Wednesday through
much of the weekend. Temperatures will be on the rise later in the
week, with highs in the upper 80s and 90s across the plains from
Wednesday into the weekend. Could see a bit cooler weather and the
possibility for a few storms at the end of the weekend into early
next week as the ridge is progged to gradually break down over the
Plains.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 522 AM MDT Mon Aug 6 2018

Some patchy fog across parts of northeast WY and southwest SD
will burn off by mid morning. Additional showers and thunderstorms
with areas MVFR conditions will develop this afternoon, mainly
across SD, then decrease this evening.

&&

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

DISCUSSION...26
AVIATION...Johnson

Hazardous Weather Outlook
National Weather Service Rapid City SD
531 AM MDT Mon Aug 6 2018

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-071145-
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-
531 AM MDT Mon Aug 6 2018 /631 AM CDT Mon Aug 6 2018/

This Hazardous Weather Outlook is for western South Dakota and
northeastern Wyoming.

.DAY ONE...Today and Tonight

There is a chance for thunderstorms this afternoon and evening.
While a stronger storm or two is possible from the Black Hills
into southwest South Dakota, widespread severe weather is not
expected.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected 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
1221 PM MDT MON AUG 6 2018

SDZ026-028-031-061915-
Pennington Co Plains-Central Black Hills-Rapid City-
1221 PM MDT MON AUG 6 2018

...AN AREA OF THUNDERSTORMS WILL AFFECT CENTRAL PENNINGTON COUNTY...

At 1220 PM MDT, strong thunderstorms were clustered 3 miles northwest
of Reptile Gardens, or 5 miles southwest of Rapid City, moving east
at 20 mph.

Locations impacted include...
Rapid City, Rapid Valley, Hisega, Rockerville, Pactola Reservoir,
Sheridan Lake, Rapid City Airport, Bear Country, Hart Ranch, Black
Gap and Reptile Gardens.

LAT...LON 4393 10354 4407 10356 4409 10301 4396 10304
TIME...MOT...LOC 1820Z 261DEG 40KT 4402 10332

Clark