Spearfish, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

239
FXUS63 KUNR 180519
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1019 PM MST Fri Jan 17 2025

.KEY MESSAGES...

-Arctic front will bring bitterly cold temperatures over the
 weekend into early next week

-Light snow will be possible at times through Saturday with a
 couple inches of accumulation in the northern Black Hills, mainly
 flurries elsewhere

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 127 PM MST Fri Jan 17 2025

Deep upper trough now building into the northern CONUS. Main cold
front has advected through the area with strong gusty winds
beginning to subside. Winds will remain breezy through Sat as the
arctic front will settle into the region and bring even colder
temperatures to the region. Snow will continue at times through
Sat over northeast WY and the northern Black Hills, with rounds of
lift and moisture supporting an increase in snowfall at times.
Cold temps expected tonight with single digits above zero for
lows. Arctic air will settle into the region Sat with the
secondary cold front. This front and associated impulse will
support another round of snow chances over the SW third, with
flurries expected most other places. Winds will uptick with this
front with breezy northwest expected most places by afternoon. The
combination of winds and temperatures will support wind chill
readings of 25 to 35 below Sat night into Sunday morning. Given
high confidence for this, have decided to issue a cold weather adv
in this period. Strong arctic high will settle into the region
through Monday, with temps likely struggling above zero by Sunday
many places in the northwestern third and possibly most places
Monday. The coldest temps are expected Monday and Tues morning as
the high will slowly move over eastern WY/western SD. Expecting
many places in the west and northwest to see lows of 15-25 below
zero both mornings, esp where clear skies, calm winds, and snow
cover overlap. Highs will again struggle above zero at many areas
Monday. This will likely necessitate the issuance of a extreme
cold warning and/or cold weather adv Sunday night into Tues
morning given apparent temperature forecasts of 25 to 45 below,
coldest in the northwest SD. Arctic high will begin to shift SE
out the area Monday night with warmer air spreading back into the
region Tues ahead of the next clipper system. Active NW flow looks
to develop afterward with highly variable temps and increased
wind. Confidence in temps and weather drop off sharply toward the
end of next week due to high variability in model solutions.
Negative AO tendencies beyond next week tend to favor another
possible arctic outbreak toward the end of the month.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 1017 PM MST Fri Jan 17 2025

Breezy north-northwest winds will persist through the evening
hours with sustained winds 10-20 knots with gusts up to 30 knots
at times. Lingering light snow/flurries continue to taper off,
with only spotty light snow showers through the overnight hours.
MVFR ceilings will persist with some transient improvement to VFR
at times. Blowing and drifting snow may result in periods of
reduced surface visibility.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Cold Weather Advisory from 8 PM MST /9 PM CST/ Saturday to 11 AM
     MST /noon CST/ Sunday for SDZ001-002-012>014-024>032-
     041>044-046-047-049-072>078.
WY...Cold Weather Advisory from 8 PM Saturday to 11 AM MST Sunday for
     WYZ054>060.
&&

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...SE