Spearfish, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

575
FXUS63 KUNR 022008
AFDUNR

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

.KEY MESSAGES...

- Accumulating snow over the higher northern Black Hills Tuesday
- Above average temperatures and mostly dry weather for the rest
  of the week

&&

.DISCUSSION...(This Evening Through Monday)
Issued at 104 PM MST Mon Feb 2 2026

19z surface analysis had frontal boundary from southern AB to
eastern NE with a weak trough draped across western ND/central WY.
Trough a reflection of shortwave over the Dakotas per water
vapour loop. Not much moisture available, but a few radar returns
perking up along surface trough and over the northern Black Hills.
Upper ridge over the western CONUS with next shortwave pushing
into BC, which will be the main short term weather concern.

Tonight/Tuesday, upper ridge builds over the western CONUS as BC
shortwave slips southeastward into the northern Plains. This
afternoon`s shortwave exits the CWA with subsidence/drying in it`s
wake, ending radar returns. Next shortwave brings a bit better
moisture with weak QG/frontogenetic forcing for Tuesday. 0-2km RH
perks up (90%) for the northern Black Hills as Froude numbers
become favorable (>1) for upslope flow for 6-9 hours Tuesday.
Forecast soundings suggest best lift below the DGZ with marginal
temperatures below 5500` for better snows. HREF QPF probability
>0.25" 50-80% for the northern Black Hills, but <50% for >0.50".
Have bumped up QPF/snow amounts to account (3-7" for the highest
peaks), but will hold off on headlines given lower confidence for
amounts and bulk of QPF falling during the day. WY/SD plains will
see much lighter QPF with a preference for rain/lower PoPs than
the northern Black Hills. Temperatures will be near guidance.

Thermal ridge builds into the area for the second half of the
week, but especially for Thursday when ECMWF EFI indicates 80-90%
percentile MaxT with some SoT action. Thursday should be the
warmest day of the week with record temperatures in jeopardy.
Preponderance of ensemble guidance portrays mild weather into next
weekend, especially over the southwest half of the CWA. Limited
precipitation chances Wednesday through next weekend with <20%
chance >0.01" QPF per latest NBM.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 1040 AM MST Mon Feb 2 2026

VFR conditions are expected through most of the TAF period with
gusty northwest winds diminishing this evening. A weather system
will enter far western SD and northeast WY after 12Z Tuesday
morning, bringing light snow and IFR conditions to those areas.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...15