715
FXUS65 KBYZ 311129
AFDBYZ

Area Forecast Discussion
National Weather Service Billings MT
529 AM MDT Sun Aug 31 2025

.KEY MESSAGES...

- Some light showers along with morning fog in Fallon and Carter
  Counties, otherwise dry and warm today. Fog could impact far
  southeast Montana again tonight into early Monday.

- Dry and warm Monday and Tuesday.

- Late Tuesday cold front brings cooler temps and a few light
  showers Tuesday night and Wednesday.

- Mostly dry with seasonable temps Thursday and Friday.

&&

.DISCUSSION...
Through Monday Night...

Satellite imagery shows mostly dry conditions over the region as a
ridge slowly builds from the west. There is an area of light
showers moving from the Dakotas into eastern Fallon/Carter
Counties, associated with a weak mid level trof/frontogenesis.
Also, low clouds/fog are advecting from northwest SD into the far
southeast corner of MT. Spearfish is reporting a 200` ceiling and
vsby under a mile, and this should be indicative of what we are
seeing spread toward Alzada and Albion. The remainder of the cwa
is mostly clear. A combination of low clouds, fog and light
showers will impact our far east this morning. Then, as easterly
winds persist and under a PV axis, cannot rule out a few showers
and weak t-storms in this same area this afternoon. CAMs are not
showing much convection, but it is something to watch. Everywhere
west of Fallon and Carter Counties will be mostly sunny and dry
today. Look for temps in the 80s to near 90F, except for 70s in
the far east.

Upper level ridge and above normal heights will dominate our
weather tonight through Monday night. There will likely be
fog/stratus again in far southeast MT late tonight and early
Monday. Temps will warm to the mid 80s to around 90F everywhere
tomorrow, even the far east with mixed/drier northwest winds.

Regarding fire weather: Along with the heat will come much lower
humidity these next two days. Look for min RHs in the mid teens
and lower 20s across the west. After the recent wet weather we
will need to monitor how fuels respond to a couple of warm/dry
days, although winds will remain on the light side.

JKL

Tuesday through Saturday...

An upper level ridge over the western CONUS will keep conditions
warm and dry for most of Tuesday. Then, a cold front will drop
south late afternoon/early evening, shifting winds to the
north/northeast and bringing a 20-40% chance of showers and
thunderstorms near the Dakota border Tuesday evening into
Wednesday morning. For Wednesday afternoon, upslope flow will
allow isolated showers and thunderstorms (10-20% chance) over the
mountains. Upper level ridging builds back in for the end of the
week, bringing mostly dry conditions and a warming trend. However,
by Saturday, there are signs that the pattern may become more
unsettled, although the details are still uncertain.

High temperatures Tuesday will be in the mid to upper 80s under
the upper level ridge. On Wednesday, highs will be around 5-15
degrees cooler than Tuesday, ranging from upper 60s over the east
to near 80 over the west. With the cooler temperatures, lows
Thursday morning are expected to be mostly in the 40s, with a
10-20% chance of lows less than 40 near the Dakota border. Then,
as ridging builds in, highs will increase through the end of the
week, reaching mid to upper 80s by Saturday. Archer

&&

.AVIATION...

Areas of low stratus and fog will impact far southeast MT (mainly
east/south of KMLS) until ~18z. Expect reductions to IFR-LIFR.
Isolated showers and perhaps an afternoon weak t-storm are also
expected near the Dakotas border. Otherwise, VFR will prevail
through the period as strong high pressure aloft builds from the
west. Slant range visibility may be reduced at times due to
regional wildfire smoke, especially in the west. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    Tdy Mon     Tue     Wed     Thu     Fri     Sat
-------------------------------------------------------
BIL 088 057/089 058/090 056/079 053/084 053/081 052/084
    0/U 00/U    00/U    11/U    00/B    01/U    01/U
LVM 086 049/088 050/089 051/084 050/085 049/082 049/081
    0/U 00/U    00/U    01/U    00/B    01/U    12/T
HDN 088 053/089 054/090 053/078 049/083 049/081 049/085
    0/U 00/U    00/U    11/B    00/B    00/U    00/U
MLS 085 056/088 057/087 054/073 048/080 049/076 047/080
    0/U 00/U    00/U    20/B    00/B    00/U    00/U
4BQ 080 055/085 056/085 054/071 048/078 049/075 049/081
    0/U 00/U    00/U    30/B    00/B    00/U    00/U
BHK 077 051/085 053/083 049/069 041/076 045/074 044/078
    2/T 00/U    01/U    40/B    00/B    00/U    00/U
SHR 084 050/087 051/088 050/076 047/080 048/078 048/082
    0/U 00/U    00/U    12/W    00/B    01/U    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.

&&

$$
weather.gov/billings