518
FXUS63 KUNR 131951
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
151 PM MDT Sun Jul 13 2025

.KEY MESSAGES

-Continued dry today with temps warming up through Monday

-Marginal Risk (1/5) for severe thunderstorms Monday and Tuesday

-Unsettled conditions Wednesday through Thursday with a
 significant cool down for Wednesday

-Semi-unsettled and warmer by the end of the week

&&

.DISCUSSION...(This Evening Through Sunday)
Issued at 123 PM MDT Sun Jul 13 2025

Upper-level ridging remains in place across the central Plains
which has allowed for clear skies and dry conditions across all of
eastern Wyoming and western South Dakota. On Monday the ridge axis
shifts to the eat, allowing for modest southwesterly flow aloft
and surface warming. Highs will climb into the mid to upper 90s
across the plains with some pockets of triple digit temperatures
near the Cheyenne river valley. A weak shortwave embedded in the
flow may trigger isolated convection late Monday afternoon.
Convective parameters are weak with forecast soundings showing
MLCAPE values between 500-1000 J/kg and weak shear. There is a
Marginal Risk for severe weather tomorrow across the Black Hills
with small hail and severe wind gusts being the primary hazards.

A more amplified trough will dig into the northern Rockies
Tuesday, enhancing mid-level ascent. Additionally, PWATS increase
to around 1.2-1.4" and with steeping lapse rates, scatted to
widespread showers with some embedded thunderstorms will be
possible Tuesday afternoon and evening. Again, there is a Marginal
Risk for severe weather across portions of western South Dakota
Tuesday afternoon. Small hail, gusty winds and heavy rainfall
will be the concerns. Transitioning into Wednesday, the trough
axis crosses the region and broad cyclonic flow with embedded
shortwaves will maintain the threat for widespread precipitation.
PoPs are in the 70-80% range with widespread QPF totals of 0.50"
across much of area.

In the wake of the passing trough long term models favor a return
to zonal flow and weak ridging across the central CONUS Friday
into next weekend. This sill support a warming and drying trend
with highs returning to the low 80s by Sunday. Daily isolated
thunderstorm chances will remain in the forecast but PoPs are <20%
over next weekend.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1125 AM MDT Sun Jul 13 2025

VFR conditions should prevail through the period.

&&

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

$$

DISCUSSION/KEY MESSAGES...Woodward
AVIATION...Sherburn