Headlee Ranch, South Dakota Weather Forecast Discussion

591
FXUS63 KUNR 111748
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1148 AM MDT Thu Sep 11 2025
.KEY MESSAGES...
-Seasonally very warm through Friday
-Isolated showers and thunderstorms through Friday with a good
 chance of widespread rain Friday night into the weekend
&&
.DISCUSSION...(Today Through Wednesday)
Issued at 336 AM MDT Thu Sep 11 2025
09Z upper level analysis has the forecast area under southwest
flow, with ridge to the east and large closed low to the west.
Shortwave energy in southwest flow continues to bring waves of
isolated to scattered rain showers and thunderstorms through the
forecast area overnight. At the surface, low pressure resides
across eastern Montana, with warm frontal boundary across ND, and
cool frontal boundary extending southwest into Wyoming. Ahead of
the low, broad southeast boundary layer flow is in place, with
very mild temperatures across the forecast area at 3 AM - in the
60s to lower 70s.
Region will remain in disturbed southwest upper flow today with
surface low settling into far southeast Montana and far northwest
SD. With ample moisture and heating today, isolated to scattered
strong to severe storms will be possible across much of the area
late this afternoon and evening, especially in the vicinity of the
surface low and just to the north of the low across southeast
Montana into southwest ND. At this time, there is a Marginal (1
out of 5) risk of severe storms across much of the forecast area,
with a Slight (2 out of 5) risk just to the northwest of the
forecast area in southeast Montana and southwest ND. Hail and
strong gusty winds are the main concern with any storm that
develops today into tonight.
Unsettled southwesterly flow continues into Friday, with isolated
thunderstorms possible. Late Friday, a stronger shortwave ejects
out of the western upper trof/low, bringing widespread rain and
isolated storms to much of the area. Upper trof shifts into the
Rockies on Saturday, with rain continuing across much of the
forecast area. Rainfall totals approach an inch from the Black
Hills into northwestern SD by Sunday morning. Temperatures over
the weekend will fall closer to seasonal averages.
Upper trof lifts north and east of the area Sunday night into
Monday, with weak ridging and drier weather for early next week.
The break in unsettled weather is short-lived, as another upper
trof swings into the Northern Plains for the middle to latter half
of next week.
&&
.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1147 AM MDT Thu Sep 11 2025
Mainly VFR conditions are expected today into tonight. Isolated to
scattered thunderstorms will be possible across most of the area
this afternoon into tonight, with brief MVFR conditions in the
vicinity of stronger storms. Best chances for storms in and around
KRAP and KGCC will be from 22Z through 03Z.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...15
AVIATION...Dye

NWS UNR Office Area Forecast Discussion