544
FXUS63 KUNR 151749
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1149 AM MDT Tue Sep 15 2026

.KEY MESSAGES...

- Unsettled temperatures continue this week

- Elevated fire weather conditions return Wednesday for northeast
  WY

- Multiple weak precipitation chances this week, with the best
  chances Thursday into Friday and this weekend

&&

.DISCUSSION...(This Afternoon Through Monday)
Issued at 1121 AM MDT Tue Sep 15 2026

Current upper-air analysis and water vapor imagery depict
southwesterly flow and drier air over the region, with the next
system to watch moving into the PNW. Satellite imagery indicates
clear skies under high pressure. Surface observations show
temperatures mainly in the 50s and 60s, with dewpoints in the mid
30s to mid 40s. Northwesterly winds across the SD plains are light
at ~10kts, while east-southeasterly winds across northeast WY and
far southwest SD are at ~15kts.

Due to the position of the jet stream to our south, today is looking
to be a nice fall-like day with highs in the upper 60s to mid 70s
with lighter winds under clear skies. Fire weather concerns have
backed off some today with RH`s in the mid to upper 20s to low 30s
and lighter winds. There will be a chance for light showers and
possibly a couple thunderstorms late tonight into tomorrow morning
across the SD plains, though this will be very spotty with minimal
accumulations for most.

Wednesday looks to be on the warmer side as the jet stream shifts
toward the north, with highs in the upper 70s to mid 80s. Breezier
conditions will also return throughout the day for both western SD
and northeast WY. The combination of warmer temperatures, breezy
winds, and RH values in the low to mid 20s across northeast WY will
lead to elevated fire conditions.

Chances for precipitation will return Thursday/Friday as a shortwave
moves across the region as an upper-level low spins over northern
CA/western OR. Currently, south-central SD has the best chance at
picking up meaningful precipitation amounts, while far western SD
and northeast WY may struggle to pick up some desperately needed
moisture. Chances for precipitation will continue through the
weekend as the upper low moves across the region.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)
Issued At 1149 AM MDT Tue Sep 15 2026

Southeast winds are expected to increase between 20-22z/2-4pm MDT
this afternoon, then remaining breezy through the forecast period
including overnight tonight. A few showers can`t be ruled out
late tonight as well (especially in South Dakota), but current
confidence and probabilities are too low to include any PROB30s.
Significant impacts are not expected from this activity, if it
develops, with VFR conditions throughout the period.

&&

.FIRE WEATHER...
Issued At 1121 AM MDT Tue Sep 15 2026

Elevated fire weather conditions return Wednesday as warmer
temperatures (upper 70s to mid 80s), breezy winds, and RH values
in the low to mid 20s return to northeast WY. Conditions improve
Thursday as cooler temperatures, higher RH values, and a chance
for precipitation return to the area.

&&

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

&&

$$

DISCUSSION...Schultz
AVIATION...KSmith
FIRE WEATHER...Schultz