Comanche, Montana Weather Forecast Discussion

312
FXUS65 KBYZ 290834
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
234 AM MDT Mon Sep 29 2025
.KEY MESSAGES...
- Temperatures 10-20 degrees above average through Thursday.
- 20-40% precipitation chances Tuesday across the lower
  elevations. Less than 0.10 inches expected.
- Pattern change expected late Thursday into the weekend with a
  change to cooler and wetter conditions.
- High elevation (>8,000 ft) snow Thursday night through the
  weekend.
&&
.DISCUSSION...
Today through Sunday...
Highs look to remain 10-20 degrees above normal, in the upper 70s
and 80s for most locations, through Thursday before the next
notable system moves through.
Upper level southwest flow will allow a 20-50% chance for light
showers, primarily over the mountains, today through Wednesday. On
Tuesday, a 20-40% chance of showers will spread over the plains
as far east as Miles City. Weak, isolated thunderstorms are also
possible (10-20% chance), with gusts of 30-40 mph as the main
threat. Even Tuesday, any precipitation that falls over the plains
will be light, with generally a less than 10% chance of at least
0.1".
Beginning late Thursday, a Pacific trough moving inland is
expected to impact the region. There are still disagreements
between the models on the strength of this system, however, timing
has come into better agreement. There is moderate confidence in
more widespread precipitation Thursday evening into Friday
afternoon, with a few showers lingering over the southeast into
early Saturday morning. Currently, the NBM has a 30-50% chance of
at least 0.1" over the plains and 50-70% chance of the same over
the mountains and foothills Thursday through Saturday. Cooler
temperatures will accompany this round of precip, with snow levels
falling between 8000 and 9000 ft, allowing a 20-40% chance of at
least 3 inches of snow over the highest mountain peaks.
Late Saturday, a wave is expected to drop south out of Canada
through the upper level flow and set up to the west, bringing
additional rounds of precip through at least the early part of the
next week. The exact details on this system are still uncertain
at this time. Currently, model spread for snow over the highest
peaks of the Absaroka/Beartooth mountains varies from less than 1
inch for the 25th percentile to nearly a foot for the 75th
percentile. This will be something to watch.
There is high confidence in a cooling trend late Thursday through
the weekend, with highs by Sunday around 20 degrees cooler than
Thursday, in the 50s to low 60s. For locations west of Billings,
there is a 20-40% chance of highs less than 50 F Sunday. Archer
.AVIATION...
Scattered showers and isolated thunderstorms are expected to
develop over the mountains/foothills and mostly remain there
through the afternoon. VFR conditions will persist through the
period. TS
&&
.PRELIMINARY POINT TEMP/POPS...
Tdy Tue     Wed     Thu     Fri     Sat     Sun
-------------------------------------------------------
BIL 083 056/084 054/080 053/077 050/062 044/065 042/056
    0/U 01/B    20/U    01/B    54/W    21/B    23/W
LVM 080 049/076 046/074 044/071 040/058 034/061 031/053
    3/T 12/T    21/B    23/W    64/W    11/B    33/W
HDN 084 051/086 052/081 049/079 048/065 040/066 039/059
    0/U 00/B    40/U    11/U    54/W    21/B    22/W
MLS 086 056/087 057/083 053/081 052/067 044/067 041/060
    0/U 00/U    10/U    00/U    43/W    11/B    11/B
4BQ 085 057/086 057/080 054/081 051/065 044/063 043/059
    0/U 00/U    10/U    00/U    33/W    21/B    11/B
BHK 085 054/088 053/082 050/081 048/068 040/068 040/061
    0/U 00/U    00/U    00/U    32/W    11/B    11/B
SHR 083 049/083 047/079 047/080 043/063 036/063 035/057
    1/B 01/B    20/U    01/U    45/W    32/W    22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings

NWS BYZ Office Area Forecast Discussion