Spearfish, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

409
FXUS63 KUNR 251615
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1015 AM MDT Sat Apr 25 2026

.KEY MESSAGES...

- Cooler and unsettled through the weekend with on and off
  precipitation.

- Gradual warm up towards the end of the forecast period.

&&

.UPDATE...
Issued at 949 PM MDT Fri Apr 24 2026

Latest water vapour loop had upper low spinning over southern SK,
pinwheeling multiple shortwaves around it. One 90kt jet streak
assisting (mostly) rain across southeast third of the CWA per
regional radar loop/IR enhancement. Even some isolated thunder
noted this evening. Wave will continue to support some rain/snow
overnight into Saturday as it slowly slips away. Some indication
in latest CAMS that spirited snow showers may develop over Black
Hills Saturday afternoon. Next wave arrives for Sunday/Monday as a
broad area of QG-forcing/frontogenesis moves from the Rockies into
the plains. Probabilistic guidance has been persistent with
painting beneficial QPF over the CWA, especially the southeast
half.

Forecast tweaked and updated to address these thoughts.

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 137 PM MDT Fri Apr 24 2026

Current Water Vapor an upper air models show the upper low over
southern SK/MB, with a jet streak over the southern half of the
forecast area. 18Z surface analysis depicts surface high over
eastern SD this afternoon, surface low over eastern WY with a warm
front stretching into western NE. Radar shows widespread light
precipitation across the forecast area with a mix of rain/snow
depending on location. Winds are generally light out of the
northwest, with temperatures ranging from the 40s and 50s over
the plains, upper 20s and 30s over northeastern WY and the Black
Hills.

Upper low slowly lifts northeastward over the weekend. Meanwhile
multiple disturbances circling the low will bring on and off light
precipitation through the weekend. Still some model discrepancy
on the locations of best forcing with these disturbances, however
ensemble guidance points towards the highest QPF amounts being
over the Black Hills, and southwestern to south central SD through
the weekend. 72 hr prob for >= 0.5" through the weekend has nice
signal for 50-70% in these locations. Areas may see a break in the
precipitation Saturday, but a stronger waver moves through the
region Saturday night into Sunday, bringing more widespread
rain/snow across the area. The main push of precipitation will
exit the region early Monday, with drier but still unsettled
conditions expected through the work week. A few weak disturbances
may bring some areas of light precipitation, but not as
widespread as this weekend. Temperatures remain relatively
stagnant through the first half of the week as well, with little
change in the overall pattern. We do see a gradual warmup back
into the 50s and 60s the latter half of next week as the upper low
shifts over the far eastern CONUS.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1009 AM MDT Sat Apr 25 2026

MVFR-IFR conds will linger across south central South Dakota and
around the Black Hills this afternoon, with scattered snow
showers. Otherwise, VFR conditions expected elsewhere. The next
system will slowly move into the area tonight, with MVFR-IFR cigs
spreading northward through the region on Sunday.

&&

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

$$

UPDATE...Helgeson
DISCUSSION/KEY MESSAGES...Dye
AVIATION...MLS