336
FXUS63 KUNR 291119
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
419 AM MST Sat Nov 29 2025

.KEY MESSAGES...

- Snow/blowing snow winds down today leaving cold weather (10-20F
  below normal) in it`s wake for the weekend
- Semi-unsettled weather expected next week with limited chances
  for impactful weather except for some upslope snow for the
  northern Black Hills

&&

.DISCUSSION...(Today Through Friday)
Issued at 216 AM MST Sat Nov 29 2025

08z surface analysis had low over south-central KS with inverted
trough into central SD and cold front behind it diving into
western NE. Water vapour loop had upper trough moving across the
northern/central Plains. Expansive area of snow per regional
radar/IR loops with back edge of best lift approaching the SD/WY
border. Disposition of upper trough continues to be the main
forecast concern.

Today, upper trough takes QG/frontogenetic forcing away this
morning with subsidence/drying moving from west to east across the
CWA this afternoon. Additional daytime snow accumulations will be
1-2 inches mainly over the northern Black Hills (upslope) and
south-central SD (synoptic forcing). The main story will be the
blowing snow due to northerly winds gusting to 30-45mph at times.
Have adjusted Winter Weather Advisory over south-central SD to end
at 29/21z as best winds hang on there the longest. Rest of
previous headline timing looks good. Temperatures won`t do much
today with readings near guidance/10-20F below normal.

Tonight, weak high pressure moves in setting the stage for a chilly
night with lows a few degrees below zero enhanced by fresh
snowcover. Minimum wind chills as low as -20F are foreseen.

Sunday, fast-moving shortwave dives through the Rockies with weak
QG-forcing/moisture brushing the southwest reaches of the CWA.
Have introduced PoPs since signal has been in guidance for a
couple of nights, although mean ensemble PoPs/QPF is low. Chilly
temperatures continue.

Next week looks semi-unsettled under northwest flow aloft and
weak wiggles. LREF guidance not painting anything too impactful.
Periodic bouts of light QPF may occur. Temperatures will moderate
except for Wednesday when a better kick of cold air moves through.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 418 AM MST Sat Nov 29 2025

Widespread IFR/MVFR conditions due to snow and blowing snow will
taper off from west to east today, especially this afternoon as
conditions improve to VFR tonight.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 11 AM MST this morning for SDZ001-
     002-012>014-024>032-041>044-072>078.
     Winter Weather Advisory until 3 PM CST this afternoon for SDZ046-
     047-049.
WY...Winter Weather Advisory until 11 AM MST this morning for WYZ057-
     060.
     Winter Weather Advisory until 8 AM MST this morning for
     WYZ054>056-058-059.
&&

$$

DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Helgeson