344
FXUS63 KUNR 082316
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
516 PM MDT Fri Aug 8 2025

.KEY MESSAGES...

-  Marginal (level 1 of 5) risk of severe thunderstorms late this
   afternoon/evening.

- Dry pattern expected throughout the weekend and into next week.

- Seasonal temperatures expected.

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 115 PM MDT Fri Aug 8 2025

A cold front has pushed through all of western SD late this
morning and in its wake a cooler and drier airmass has advected
into the region. Water vapor and VIS shows a broad closed low
spinning across northeastern Montana with a clear defined dry slot
wrapping up near the center. This dry slot is rapidly moving
eastward and will bring drier air to much of the region tonight.
With clearing skies, weakening winds and the drier and cool air
advection lows tonight across the Black Hills could drop into the
40s in some locations. As the main area of low pressure/trough
approaches the area some residual CAPE values around 1000 J/kg are
hanging around the plains and points east. With large amounts of
shear, any storms that do initiate could pose a small window of a
severe threat although CAMS and Hi-RES models don`t seem to
excited about CI (Convective Initiation) this afternoon and even
the Storm Prediction Center has pulled the Marginal Risk almost
completely out of our area for this afternoon and evening.

Heading into the weekend, the pattern begins to shift toward a
prolonged period of dry weather with temperatures warming to
seasonal as the winds aloft switch from the Northwest to the
southwest as upper level ridging begins to build across much of
the western CONUS. Predominately dry conditions with gradual
warming temperatures can be expected through much of next week.
Some diurnal low end PoP chances will be possible by midweek.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 514 PM MDT Fri Aug 8 2025

Isold TS are possible through 09/02Z across the nrn Black Hills
and down near KIEN. Brief gusty winds are possible with some of
the stronger storms as they pass through. Otw VFR conds are
expected through the valid fcst period.

&&

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

$$

DISCUSSION/KEY MESSAGES...Woodward
AVIATION...Hintz