Gillette, Wyoming 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

497
FXUS63 KUNR 130338
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
938 PM MDT Thu Jun 12 2025

.KEY MESSAGES...

-Unsettled into next week with near daily chances for showers and
 storms, some possibly severe at times

-Areas of fog possible late tonight into Friday morning, mainly
 on the SD Plains

-Seasonal temps most of the period

-Smoke/haze possible through the period from Canadian wildfires

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 111 PM MDT Thu Jun 12 2025

Unsettled westerly flow will continue into next week as a series
of impulses eject out of the NE Pac upper low. Frontal boundary
has stalled over the region, with low clouds, haze, and cool temps
to the north. Tail end of the front will be the focus for
thunderstorm development this afternoon across south central SD.
ML CAPE of 1-2 KJ/KG will be in place with 35-45 knots of bulk
shear, supporting the potential for a severe cells into this
evening. Another area of TS will develop this evening across
eastern WY and will shift northeast overnight, into the BH
region. Isolated hail and wind will be possible with these storms,
but CAPE will be much more limited given expected elevated nature
of storms. Convection will shift east overnight and wane in
western SD. With moist easterly upslope flow continuing, expect
areas of fog to develop across portions of western SD. Frontal
boundary will again be stalled over the region Friday as another
impulse shifts into the region. TS are expected to develop INVOF
of the sfc trough in northeast WY by mid afternoon, with a
convective complex expected to develop and shift east. Staunch
capping will prevent cell development over the BH until maybe late
in the afternoon/early evening when the shortwave arrives. Severe
storms will be possible once again in the western third where
sufficient CAPE and bulk shear will overlap. As convection shifts
east, it will have difficulty maintaining into western SD given
capping, overall less CAPE, and diurnal cooling, which is in line
with hires progs. Hence, have kept pops in the low chance range
there for now. Frontal boundary will reside over the region this
weekend into next week with deeper moisture increasing as gulf
moisture pools over the area INVOF the front. This will likely
support rounds of severe weather as the flow shifts to more WSW
aloft and impulses eject out of the mean eastern Pac upper trough.
Temps will be seasonal in this period as well, with highs in the
70s and 80s and lows in the 50s and 60s.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 936 PM MDT Thu Jun 12 2025

Thunderstorms may move into northeastern WY and southwestern SD
tonight, with brief MVFR conditions possible.

Low stratus with MVFR/IFR CIGS across NW SD will spread southwest
into the Black Hills region tonight, with patchy fog reducing
VSBY. Conditions will gradually improve to VFR Friday afternoon.

Another round of thunderstorms will be possible across northeastern
WY and far western SD Friday evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Pojorlie