705
FXUS63 KUNR 202254
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
454 PM MDT Mon Jul 20 2026

.KEY MESSAGES...

- Cooler temps expected Tuesday through Thursday.

- Rain through midweek to bring beneficial moisture.

- Hot and dry weather returns next weekend.

&&

.DISCUSSION...(This Evening Through Monday)
Issued at 220 PM MDT Mon Jul 20 2026

Strong ridging persists across the western CONUS with upper flow
over the CWA becoming increasingly northwesterly. Surface obs show
the cold front across SCentral SD, with showers near the boundary.
These showers will continue SE and exit the area this afternoon.
Current temps are generally in the upper 80s to mid 90s. Smoke in
the area has hindered temps from getting as warm as expected...and
likewise, apparent temps. Will leave the Heat Advisory out but could
see it being cancelled before 03z. Temps on Tuesday through Thursday
will be a cool 80s each day. After a dry day on Tuesday, a wave
pushing through is expected to bring showers and isolated
thunderstorms overnight into Wednesday morning. Most models keep QPF
on the light side, but the ECM/RRFS/NAM show some locations getting
well over half an inch. This will be possible with PWATs of 150-175%
of normal. The next series of waves will approach as the upper ridge
weakens. These slow-moving waves are expected to bring showers and
thunderstorms to the area late Wednesday into Thursday. The latest
run of the GFS shows an impressive 175-200% of normal, which could
bring localized QPF amounts of over an inch. Hot weather with +100F
temps could return for the weekend as the ridge sets up again across
the western CONUS.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 453 PM MDT Mon Jul 20 2026

VFR conditions will prevail through the TAF period. Breezy
northwest winds are expected to develop this evening and persist
into tonight. Isolated showers/storms will be possible over the
Black Hills and western SD plains this evening, but low confidence
that they`ll go over the TAF sites.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 9 PM MDT /10 PM CDT/ this evening for SDZ026-
     027-030>032-041>044-046-047-049-072>077.
WY...Heat Advisory until 9 PM MDT this evening for WYZ055-058-059.
&&

$$

DISCUSSION...13
AVIATION...Wong