518 

FXUS63 KUNR 051846

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

1246 PM MDT Fri Jun 5 2026



.KEY MESSAGES...



- A stray shower or storm is possible this afternoon over the 

  Black Hills, otherwise it will be dry.



- Hot on Saturday. High-based storms with strong winds are 

  possible over portions of northeast Wyoming and far northwestern

  South Dakota.



- A cold front moves through Sunday with showers and 

  thunderstorms and cooler temperatures on Monday. 





&&



.DISCUSSION...(This Evening Through Friday)

Issued at 1245 PM MDT Fri Jun 5 2026



Upper level analysis has mostly zonal flow over the Northern Plains 

with a shortwave ridge on the east side of the Rockies. At the 

surface high pressure is centered over the area with an area of low 

pressure in northeastern Washington and a trailing cold front into 

northern California. Visible satellite indicates a cu field over 

northeast Wyoming, around the Black Hills, and across southern and 

easter portions of the forecast area.



Mostly sunny skies will continue through the afternoon with a slight 

chance of a diurnally, terrain driven shower or storm this 

afternoon. Dewpoints are in the 50s to low 60s over the hills could 

produce brief heavy rain. 



On Saturday it will be hot. NBM has highs in the 90s with upper 90s 

over northeast Wyoming and southwestern South Dakota. HREF spreads 

are between 90 degree and 94 degrees for KRAP whereas the NBM is 

much higher at 98 degrees. With all the recent rain and greenness 

around, it appears the NBM is running to high. Therefore, I bumped 

down temperatures about 5 degrees over the South Dakota Plains to 

fall more in line with the HREF 25-75th percentile highs. 

  

A few high-based showers and storms are possible Saturday afternoon 

and evening over northeast Wyoming, the Black Hills, and far 

northwestern South Dakota ahead of a deepening lee cyclone. Strong 

diurnal heating combined with height falls and steep lapse rates in 

the afternoon will bring the potential for afternoon showers and 

storms. The more favored environment is over eastern Montana and 

western North Dakota, but ample shear within the forecast area could 

result in a few storms with strong wind gusts of 60+ mph.



A cold front moves through on Sunday and Sunday night, entering the 

forecast area around 12Z before exiting around 12Z Monday. Energy 

ahead of a shortwave trough aided by a jet streak and strong surface 

heating could result in some terrain driven storms. Additional 

storms will be possible during the evening along the surface front 

as the strong boundary-layer heating erodes the capping. Thus expect 

some isolated severe storms. 



Monday will be cooler across the entire forecast area behind the 

cold front. Surface high pressure will slide across the CWA through 

the day with upper level southwest flow. Another hot day is ahead on 

Tuesday with prefrontal warming before a deep upper low and another 

cold front impact the area on Wednesday and Thursday. Overall, this 

pattern will result in daily chances for showers and storms. 



&&



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

Issued At 1126 AM MDT Fri Jun 5 2026



VFR conditions are expected through the period. 



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...None.

WY...None.

&&



$$



DISCUSSION/KEY MESSAGES...MLS

AVIATION...MLS