Carlile, Wyoming Weather Forecast Discussion

731
FXUS63 KUNR 010841 CCA
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
203 AM MDT Wed Oct 1 2025
.KEY MESSAGES...
- Unseasonably warm temperatures through Friday
- Elevated fire weather conditions Thursday and Friday
- Significant pattern change for the weekend into early next week
&&
.DISCUSSION...(Today Through Tuesday)
Issued at 159 AM MDT Wed Oct 1 2025
07z surface analysis had cool front from the MT/ND border into
western WY, just sneaking into the CWA early this morning. Water
vapour loop had upper ridge centered over the Great Lakes with
upper trough approaching the northwest CONUS. CWA caught in
between under southwest flow aloft. Couple weak waves noted over
the northern Plains with some weak radar returns. Nothing over the
CWA, but may need to add low PoPs near the 40kt low level jet
east of the Black Hills and possibly along the cool front.
Today/tonight, cool front moves through the CWA with MaxT 3-5F
lower than yesterday per cooling forecast lower tropospheric
profiles. A few breezy spots behind the cool front given 2-3mb/3hr
pressure rises/20-30kt northwest boundary layer flow. Post-
frontal buoyancy scant per SPC HREF, but there is a small signal
that lee side convergence may pop a few showers over the
central/southern Black Hills/adjacent plains later this afternoon.
Chance not enough to introduce PoPs early this morning.
Thursday/Friday, dry southwest flow aloft continues as thermal
ridge builds robustly back into the area. Trend has definitely
been hotter for Friday per cold front getting hung up west of the
CWA given it`s parallel orientation to the upper flow.
Temperatures will be 15-25F above normal by Friday with the
potential for gusty winds given deep boundary layer mixing.
For the weekend, upper trough finally moves into the northern
plains with an embedded shortwave moving through (nice looking QG-
forcing blob). It will push cold front through the area while
pooling a chunk of moisture. Some guidance gives refreshing QPF
amounts (30-50% chance >0.50") liquid to the area, especially
over the northwest half Saturday night into Sunday. Not fully
convinced, but the high confidence significant pattern change
forecast lends credence to hope that the ensemble guidance is on
target. Temperatures will be much cooler, supporting a few flakes
up high at night. If skies clear Monday/Tuesday, a frost/freeze
may develop for some.
&&
.AVIATION...(For the 06Z TAFS Through 06Z Wednesday Night)
Issued At 1055 PM MDT Tue Sep 30 2025
VFR conditions will continue through the forecast period.
Gusty south-southwesterly winds will persist overnight across
portions of the area, strongest across NE WY and south-central SD
where gusts 20 to 30 knots are possible. Winds will shift
northwesterly after 14-15z Wednesday morning behind a weak cold
front/surface trough.
&&
.FIRE WEATHER...
Issued At 159 AM MDT Wed Oct 1 2025
Above normal temperatures are expected through Friday with
readings from 15-25F above average by Friday. Minimum relative
humidities should dip into the teens Thursday/Friday, particularly
over the southwest half of the CWA. Expect gusty winds at times,
which may support Fire Weather headlines (30% chance >25 gusts
Thursday, 40-80% chance >25 gusts Friday). However, the strongest
winds might not overlap the lowest relative humidities. Regardless,
at least elevated fire weather conditions sure to unfold. High to
very high grassland fire danger over the southwestern SD plains
expected. A cold front will bring relief for the weekend with
increasing chances for wetting precipitation.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...SE
FIRE WEATHER...Helgeson

NWS UNR Office Area Forecast Discussion