784
FXUS63 KUNR 061742
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1142 AM MDT Tue Oct 6 2026

.KEY MESSAGES...

-Cool front will knock temps down some Tue through Thur, however
 it will remain mild and dry

-Warming back up Friday and Saturday

-Pattern change next week will bring much cooler weather with some
 chances for precip

&&

.UPDATE...
Issued at 922 PM MDT Mon Oct 5 2026

Cool front will move through tomorrow, supporting a slightly
cooler day most areas, but still above normal. Expect highs in the
low to mid 80s most areas. Flatter flow aloft will support cooler
weather Wed and Thur as another backdoor cool front moves
through, with highs mainly in the 70s. Staunch upper level
ridging ahead of the digging western CONUS upper trough will
support very warm weather Fri and Sat before a strong cold front
moves through and significantly cools things down for next week.
Chances for precip will also return next week. However, large
model spreads remain per the track and strength of the upper
trough and its resultant local precip chances, with low confidence
in this period.

&&

.DISCUSSION...(This Evening Through Monday)
Issued at 119 PM MDT Mon Oct 5 2026

Visible satellite shows clear skies for most of the Great Plains. An
upper low spinning over northern CA/OR/NV is shedding upper clouds
across the northern Rockies. The inject of moisture into the
northwest flow may bring these cirrus over the area tomorrow. 18Z
surface analysis depicts a warm front oriented zonally across South
Dakota slowly drifting northward and bringing hot and dry conditions
to our area today. Highs over most of the area are in the upper 80s
with localized spots of 90+. Deep mixing will keep conditions dry.
Western South Dakota and northeastern Wyoming will see relative
humidities in the teens, while central SD will be closer the 30s.
Winds today will be light for most of the area, however surface
troughing across south-central SD will support wind gusts between 30
and 35 mph. Although the overlap of wind and lack of moisture do not
necessitate a Red Flag Warning, fire weather concerns are still
valid today due to dry conditions.

Temperatures for Tuesday will remain warm but not to the degree we
will see today. Highs in the mid 80s around the I90 latitude,
lowering to 80 to the north and rising to the upper 80s to the
south. Surface pressure falls will continue through the night as the
aforementioned trough progresses east. A cool front will move
through the area on Tuesday as well, reaching the Rapid City area
right around noon. Northwest winds behind the boundary will gust
around 20 to 30 mph.

Temperatures going forward will trend down through the
end of the week. Things will stay warmer than average but high will
be in the 70s. Northwest upper flow dominates until the weekend.
Current guidance swings a longwave trough down the west coast
Saturday. As is stands now the GFS lags behind the current Euro
models, but strengthen the overall system more. WPC forecasts show
strong cyclogenesis over the Dakotas Saturday morning, with front
induced precipitation chances starting Sunday and continuing
through the start of next week. Column up to 700mb stays above
freezing so liquid precip is expected at this time. &&

&&

.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 1141 AM MDT Tue Oct 6 2026

VFR conditions are expected through the TAF period.

&&

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

$$

UPDATE...JC
DISCUSSION...Schweigert
AVIATION...Dye