Spearfish, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

476
FXUS63 KUNR 282345
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
545 PM MDT Sun Jun 28 2026

.KEY MESSAGES...

- Severe thunderstorms possible tonight over western SD.

- Strong winds expected Monday, with elevated to near-critical
  fire weather conditions.

- Cooler Monday, but gradual warmup through the week.

&&

.DISCUSSION...(This Evening Through Sunday)
Issued at 1208 PM MDT Sun Jun 28 2026

Current Water Vapor and upper air models show the upper low
currently over north central MT, with southwest flow over the
forecast area. 17Z Surface analysis shows a boundary running from
northwestern SD down into southeastern WY. Winds are currently
light out of the south to southwest. Radar has some light returns
in northwestern SD moving northeast into ND.

Main concern in the near-term will be potential for severe
thunderstorms tonight into Monday morning. Mostly dry conditions are
expected this afternoon, but southeasterly LLJ ramps up this evening
into the overnight hours, bringing moisture into the region. Surface
low is expected to develop over northeastern CO and move
northeastward into the area by tonight. As low enters the region and
LLJ increases, strong to severe storms are expected to develop.
While we could see some showers/storms develop in the early evening,
HREF and HRRR show the stronger storms starting up between 03-06Z.
CAMS currently show strong to severe storms developing in
southwestern SD and the Black hills in this timeframe, then moving
northeast. Thermal profiles will support elevated storms with hail
being the main threat from these, however strong to severe wind
gusts cannot be ruled out.

Monday will be dry but windy, as strong mixing will support wind
gusts 45 to 55 mph. A Wind Advisory has been issued for much of
western SD, including the foothills late morning into the early
evening. Another shortwave is progged to move through the
central/northern plains late Tuesday into Wednesday, supporting
the potential for some showers/storms. Southwest flow continues
though the week, with weak disturbances prompting near daily
chances for at least isolated precipitation the latter half of the
week. Upper high in southeastern CONUS also builds over the week,
supporting a gradual warmup. Temperatures climbing into the 90s
will be possible Thursday through Saturday.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 545 PM MDT Sun Jun 28 2026

VFR conditions generally remain expected this evening, overnight,
and Monday across most of the region, but breezy diurnal SW winds
this evening will relax and give way to the potential for
isolated to scattered thunderstorms overnight, some of which may
be severe. High-res guidance supports initial development between
02-04z/8-10pm over the southern Black Hills or southwest South
Dakota, with storms tracking northeast from there through the
early morning hours Monday (likely clearing KRAP by 10z/4am). Any
storm could bring brief IFR conditions, wind gusts over 40kts, and
hail. Light showers will be possible outside of this main corridor
of storms with some CAMs wetter than others even back west into
KGCC, but confidence remains low enough to only continue a PROB30
group for -TSRA at KRAP with no other predominant precip in the
forecast at the TAF terminals for now. Some lower VFR to MVFR
clouds are also possible Monday morning for a few hours in south-
central South Dakota. Skies trend clearer over the course of the
day Monday regionwide with breezy conditions developing after
14z/8am in northeast Wyoming and after 17z/11am in western South
Dakota with gusts as high as 30-35kts. Confidence in VFR
conditions is high.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 10 AM to 8 PM MDT Monday for SDZ012-013-
     025>027-030-031-041-042-072>076.
WY...None.

&&

$$

DISCUSSION...Dye
AVIATION...KSmith