FXUS63 KUNR 041725

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

1125 AM MDT Tue Aug 4 2026



.KEY MESSAGES...



- Much cooler today with lingering wildfire smoke causing hazy 

  skies.



- Mainly dry this week with hot weather returning the end of the 

  week.



&&



.UPDATE...

Issued at 956 PM MDT Mon Aug 3 2026



No major changes to the forecast this evening. The secondary cold

front has made it through the CWA and winds have diminished 

across the area. Near sfc smoke will decrease through early 

tomorrow morning, though smoke (and associated air quality 

impacts) may linger across southwest SD into northeastern WY. 

Smoke aloft may still cause hazy skies over the CWA through 

tomorrow afternoon.



&&



.DISCUSSION...(This Afternoon Through Sunday)

Issued at 1112 AM MDT Mon Aug 3 2026



Western CONUS upper ridge will retrograde and flatten as a strong

upper trough moves across interior Canada. However, the ridge 

will rebuild and support hot weather by the end of the week, with 

90s and 100s returning. Strong upper trough continues to advance 

through the Northern Plains. A cool front has moved through the 

region this morning with breezy north-northeast winds across the 

FA. However, the main cold front will push through the FA late 

this afternoon and early evening, with a period of strong winds 

expected, esp across the western SD Plains where gusts of 50 to 60

mph will be possible for a short period per pressure rise 

forecast. The strongest winds will be in the lee of the Black 

Hills, likely affecting KRAP. In addition, a batch of thick low 

level smoke from OR/WA wildfires will continue to push through the

region behind the front through tonight. The worst of the smoke 

will move through late this morning into the early afternoon. 

Conds will improve gradually overnight, but some lingering smoke 

is possible into Tues, esp across the far SW FA. Isolated 

thunderstorms will still be possible in scentral SD this evening 

along the secondary front. In addition, could still could see a 

few showers and TS across the scentral SD later tonight into Tue 

morning as the jet entrance region will overlap with a weak 

impulse passing to the south of the FA, supporting elevated 

convection. Temps will fall into the 40s and 50s tonight with a 

few 30s expected in portions of the higher Black Hills. Highs Tues

will be 10 to 15 degrees below seasonal norms mainly in the 70s, 

with 60s in the Black Hills. Western ridge will gradually rebuild 

late in the week. This will support a warm up with gradual 

increasing LL moisture as SE return flow ensues. Weak pos theta-e 

adv aloft may support isolated showers and maybe a TS Wed night 

across northeast WY and far SW SD. However, models have backed 

off on the northern extent and coverage of showers, adjusted pops

down. Also pulled pops over the BH Wed afternoon, as much drier 

BL conds are expected with weaker moisture advection into the 

area. Expect highs to be back in the 90s by Thur, with triple 

digits possible by Friday and Sat on the SD Plains. Dry weather is

expected through the weekend. Flow looks to become a little more 

active later next week as some of the longer range models 

indicate a stalled frontal boundary INVOF the FA with faster flow 

aloft and appreciable LL moisture.



&&



.AVIATION...(For the 18Z TAFS Through 18Z Wednesday)

Issued At 1125 AM MDT Tue Aug 4 2026



VFR conditions are expected through the forecast period.



&&



.FIRE WEATHER...

Issued At 1112 AM MDT Mon Aug 3 2026



Gusty northerly winds can be expected today behind a cold front. 

A period of very strong winds will arrive with the secondary front

this evening (4-7 PM) with a period of winds gusting over 50 mph 

on the far western SD Plains. Although RH's will be marginal, the 

gusty winds combined with cured fuels will support critical fire 

weather conditions on most of the SD Plains and portions of the 

northeast WY Plains. A red flag warning remains in effect into the

evening. Winds will gradually diminish overnight. Much cooler 

weather can be expected Tuesday, before hot and mainly dry weather

returns later in the week with elevated fire weather conditions.



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...None.

WY...None.

&&



$$



UPDATE...Wong

DISCUSSION...JC

AVIATION...Helgeson

FIRE WEATHER...JC