257
FXUS63 KUNR 250836
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
136 AM MST Tue Nov 25 2025

.KEY MESSAGES...

- High winds and areas of light snow persist through this afternoon.
  Gusts up to 70 mph likely across the western South Dakota
  plains.

- Colder air remains entrenched through Thanksgiving with another
  shot of even colder air this weekend plus snow chances.

&&

.DISCUSSION...(Today Through Monday)
Issued at 136 AM MST Tue Nov 25 2025

Water vapor imagery shows stout vorticity max pushing through NE
MT/W ND with shortwave trough axis extending southward through NE
WY into eastern CO. Surface cold front has surged south and east
of the area with colder air spilling into the forecast area.
Rain/snow showers are quickly shifting east of the forecast area,
with lingering light upslope snow in the Black Hills. Upper level
forcing will slowly push east of the forecast area as the trough
pivots into the Upper Midwest by 00Z tonight, with snow
diminishing rapidly this afternoon. Another inch or two is
possible across the Black Hills, with little to no accumulation
elsewhere.

High winds remain on track this morning into the afternoon. Steep
lapse rates, strong cold air advection, and 40-50+ knot winds atop
the mixed layer will support wind gusts up to 65-70 mph from NW SD
through the Pennington County plains into south-central SD today.
The winds will quickly diminish from west to east after 22-00z
this afternoon.

Northwest flow will continue Wednesday into Thanksgiving with
below average temperatures (~5-10F below normal) and generally dry
conditions. A few light snow showers/flurries are possible
Wednesday in the Black Hills as a weak wave ripples through the
northwest flow.

A much more active pattern is in store Friday through the weekend.
Split flow is forecast to develop by late Friday following an
initial shortwave that pivots through the Northern Rockies into
the Northern Plains by 00z Saturday. Given the messy, split flow,
ensembles show wide spreads re: surface low development and
location, which will have a large impact on overall snow threat.
However, broad large-scale ascent will be present Friday into
early Saturday and again Sunday with near-daily chances of light
snow Friday through Monday. The current forecast has the best
threat of accumulating snow (~70%+ probability of snow >4" Friday-
Monday AM) in the Black Hills given upslope enhancement; much less
confidence in snow potential elsewhere. In addition to the snow
chances, much colder air will surge into the region with highs in
the teens and 20s Sunday-Monday and lows near 0F each night.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night)
Issued At 1003 PM MST Mon Nov 24 2025

Main aviation concern through this valid TAF period will be the
strong NW winds that will increase across the terminals after 06z
and continue throughout this TAF period. Winds have a high
likelihood of gusting up to 60 mph at the KRAP terminal with gusts
in the 40-45 mph range at the KGCC terminal. With this winds we
can expect some low level wind shear impacts at the KRAP terminal
developing around 14z.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning until 5 PM MST /6 PM CST/ this afternoon for
     SDZ001-012-013-025-026-031-032-041-043-044-046-047-049-072-
     073-077-078.
     Wind Advisory until 5 PM MST this afternoon for SDZ002-014-027-
     030-042-074>076.
WY...High Wind Warning until 5 PM MST this afternoon for WYZ060.
&&

$$

DISCUSSION/KEY MESSAGES...SE
AVIATION...Woodward