565
FXUS63 KUNR 152317
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
517 PM MDT Wed Jul 15 2026

.KEY MESSAGES...

- Hot temperatures continue through the weekend with elevated to
  near critical fire weather conditions.

- Isolated thunderstorms Thursday and Friday - mainly Black Hills
  and northeast Wyoming - with scattered thunderstorms this
  weekend across the entire area.

- Unsettled and cooler next week.

&&

.DISCUSSION...(This Evening Through Wednesday)
Issued at 1243 PM MDT Wed Jul 15 2026

High pressure continues to be centered over the Central Great Plains
with water vapor imagery showing moisture streaming into the Desert
Southwest up into the Rockies. At the surface, an area of low
pressure is centered over southeast Montana with a warm front
extending through southern North Dakota, a lee trof along the
Bighorns, and a cold front extending into northwest Wyoming.
Temperatures at 19Z are in the 90s, with a few spots around 80 in
the higher Black Hills. Winds are generally south to southeast at
5 to 15 mph.

The cold front will slowly slide into the forecast area tonight
as the surface low pushes into southwestern North Dakota and
eventually into south-central North Dakota by Friday morning. The
main impacts with the cold front will be limited. Winds behind the
front will be northerly, high temperatures will be a degree or
two cooler, and there will be a chance for afternoon and evening
thunderstorms.

Low level moisture begins to increase Thursday morning as the upper
ridge begins to slowly break down. The increase in moisture combined
with an increase in instability may allow for isolated thunderstorms
behind the cold front on Thursday and Friday. There will be greater
chances for storms this weekend as the upper ridge shifts eastward,
monsoonal moisture streams into the area, some small vorticity maxes
move through the flow, and modest ascent along the frontal
boundary.

Models differ slightly on how fast the upper ridge collapses and the
positioning of the surface fronts this weekend. However, the overall
pattern will lead to a chance for scattered storms this weekend,
with unsettled weather and cooler temperatures next week.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 514 PM MDT Wed Jul 15 2026

VFR conds through the period. Isolated showers or TS are possible
across the Black Hills and northeast WY Thur afternoon. Gusty
winds are expected near any showers.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 9 PM MDT /10 PM CDT/ Thursday for SDZ001-002-
     012>014-025>027-030>032-041>044-046-047-049-072>078.
WY...Heat Advisory until 9 PM MDT Thursday for WYZ054>056-058>060.
&&

$$

DISCUSSION...MLS
AVIATION...JC