418
FXUS63 KUNR 030247
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
747 PM MST Mon Nov 2 2026

.KEY MESSAGES...

- Strong northwest winds continue today and tonight - gusts of 40
  to 60 mph.

- Rain changes to snow across the higher elevations of the
  northern Black Hills this afternoon where 4 to 6 inches of snow
  is possible by Tuesday morning. Uncertainty in amounts given
  melting plus timing of transition to snow.

- Dry Tuesday through rest of the week.

&&

.UPDATE...
Issued at 744 PM MST Mon Nov 2 2026

Quick look at new 00z guidance in line with latest KUDX radar
loop over the northern Black Hills. Should see several more inches
of snow accumulation, mainly above 5500 feet with Winter Weather
Advisory totals still plausible (3-6"). Locally higher amounts
possible, but drier air isn`t too far away (approaching WY/MT/SD
border area) per latest nighttime microphysics RGB. Rest of
forecast still in good shape with a few wind gusts of 45mph+ for
the Wind Advisory. Will continue to monitor and drop the Wind
Advisory as needed through the night.

UPDATE Issued at 616 PM MST Mon Nov 2 2026

Latest 01z surface observations showed wind gusts have dropped
off early this evening as best pressure rises shift southward into
NE. Still seeing gusts around 45kts over portions of western SD,
so have kept current Wind Advisories in effect and downgraded the
High Wind Warning to an Advisory.

&&



.DISCUSSION...(This Evening Through Monday)
Issued at 1245 PM MST Mon Nov 2 2026

Water vapor imagery shows shortwave lifting north of the forecast
area along with another stout shortwave trough ejecting into the
central and southern Plains. Surface low is centered over ND/SD/MN
border with cold front stretching southward into western KS and a
second surface low over west-central KS. Northwest winds continue
across the forecast area. Gusts have started to come up over the
past hour with 50-55 mph gusts across Meade and Pennington counties.
Expect wind gusts to increase through the afternoon with occasional
gusts to 60 mph through the evening hours across Fall River and
portions of western SD plains where a High Wind Warning remains in
effect. Elsewhere, gusts 40 to 50 mph are expected through the
evening hours.

Precipitation has increased across the northern Black Hills over the
past few hours given upslope enhancement. The models have been too
quick with the transition from rain to snow across the Hills compared
to observations, leading to unrealistic snow accumulation that
has yet to materialize. Starting to see the transition to all snow
now across the higher elevations of the Black Hills, which will
continue through 22z. Melting and timing of transition to all
snow introduce considerable uncertainty regarding final amounts,
especially below 5500 feet. Have issued a Winter Weather Advisory
for the Wyoming and northern Black Hills where 4 to 6 inches of
snow is possible by 12z Tuesday. Heaviest snowfall will be limited
to areas above 5500 feet, with locally higher amounts possible.
Lesser amounts (~an inch or less) for lower elevations. Snow will
end early Tuesday morning with light rain lingering across south-
central SD into the late morning/early afternoon.

Upper trough forecast to push through the Central Plains Wednesday
with light rain possible across south-central SD. Otherwise,
generally dry weather expected through the week with seasonable
temperatures. Brisk northwest flow next Saturday as clipper drops
out of Canada with wind gusts > 40 mph possible and precipitation
northeast of the area.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 430 PM MST Mon Nov 2 2026

Strong gusty northwest winds (40-50kt gusts) will continue this
evening, but then slowly wane after 03/06z. Areas MVFR/IFR
conditions due to precipitation (rain on the western SD plains,
rain/snow on the northeastern WY plains) will continue this
evening, but then wane from northwest to southeast overnight.
Local LIFR conditions due to snow/stratus will occur in/near the
northern Black Hills tonight. Conditions across northeastern
WY/far western SD will trend VFR Tuesday morning and then east of
the Black Hills later Tuesday afternoon.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 6 AM MST /7 AM CST/ Tuesday for SDZ001-002-
     012>014-032-043-044-046-047-049-076>078.
     Winter Weather Advisory until 5 AM MST Tuesday for SDZ024.
     Wind Advisory until 5 AM MST Tuesday for SDZ026-027-030-031-041-
     042-072>075.
WY...Winter Weather Advisory until 5 AM MST Tuesday for WYZ057.
&&

$$

UPDATE...Helgeson
DISCUSSION...SE
AVIATION...Helgeson