315
FXUS63 KUNR 170516
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1016 PM MST Thu Jan 16 2025

.KEY MESSAGES...

-Strong cold front arrives Friday with gusty northwest winds and
 falling temperatures

-A bit of light snow/flurries on the plains with a few inches of
 accumulation in the northern Black Hills Friday through Saturday

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

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 1254 PM MST Thu Jan 16 2025

Pac northwest flow will give way to long trajectory northerly
flow, supporting the coldest air of the winter so far as arctic
air heads into the region. Potent clipper system will take aim at
the region Fri and allow for increasing chances for snow/flurries,
esp over NE WY and the BH. The other main impact from this system
will be gusty northwest winds with gusts up to 55 mph possible on
the SD plains, esp in the lee of the BH. Snow amounts are
expected to be minimal with this system through Sat with 1 to 3
inches possible in the northern BH, and an inch or less in
northeast WY, with a dusting elsewhere. Cold air will settle into
the region tomorrow, with highs expected in the morning and
falling temps through the day most places. 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 in
over the SW third, with flurries expected most other places.
Strong arctic high will settle into the region through Sunday,
with temps likely struggling above zero by Sunday many places in
the western third to half. The coldest temps are expected Monday
morning as the center of the high will move over eastern WY/far
western SD. Expecting many places in the west and northwest to see
lows of 20-30 below zero Monday, esp where clear skies, calm
winds, and snow cover overlap. Highs will again struggle above
zero at many areas Monday. Cold weather adv and extreme cold
warnings will likely be needed for much of the area Sunday into
Monday. Arctic high will begin to shift SE out the area Monday
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.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 1013 PM MST Thu Jan 16 2025

VFR conditions are expected through today and tonight. Early
Friday morning (after 05-07z), an Arctic cold front will begin to
slide through the region. Ceiling/visibility will become MVFR/IFR
across northeastern WY Friday morning as low clouds sag into the
area. Snow showers are expected to accompany the front, but
confidence in timing/duration is low at this time. Highest
probability for MVFR/IFR conditions in the Black Hills.

Northwesterly winds will increase to 20 to 30 mph with gusts up to
50 mph, especially over the western SD plains, after 16-18z Friday
morning. Before these strong winds reach the surface, there could
be some LLWS over parts of the area tonight.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 8 AM MST /9 AM CST/ to 5 PM MST /6 PM CST/
     Friday for SDZ001-002-012>014-026-030>032-042>044-046-047-
     049-072-073-077-078.
WY...None.
&&

$$

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