Wan I Gan, Montana Weather Forecast Discussion

212
FXUS65 KBYZ 300849
AFDBYZ
Area Forecast Discussion
National Weather Service Billings MT
249 AM MDT Tue Sep 30 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.
- Snow for the mountains and possibly the foothills Thursday night
  through early next week.
&&
.DISCUSSION...
Today through Monday...
A shortwave moving through the flow will bring a 20-40% chance of
precipitation today into early Wednesday, beginning over the
mountains this afternoon and spreading across the plains by the
evening. Outside of the mountains, any precip is expected to be
light, with generally a less than 20% chance of more than 0.1"
through Wednesday morning. Over the Absaroka/Beartooth mountains,
snow levels will fall to around 10k feet overnight, allowing for
very light snowfall (20% chance of more than 0.1") over the
highest peaks. Isolated (10-20% chance) thunderstorms will also be
possible, although no strong storms are expected. The main threat
with any storms will be gusts around 30 to 40 mph.
Wednesday afternoon into Thursday morning, upper level flow
remains southwesterly, allowing isolated (10-30% chance) showers
over the western mountains and foothills. Otherwise, conditions
will remain mostly dry ahead of the next system moving in late
Thursday.
Late Thursday, a Pacific trough is expected to move inland,
bringing more widespread precip through at least Friday. Precip
amounts over the plains are still expected to remain mostly
light, with a 30-50% chance of at least 0.1". Over the mountains,
there is a 40-60% chance of at least 0.25" of precip, including a
chance (30% of more than 3 inches) of snow above 10k feet over the
Absaroka/Beartooth mountains.
How the pattern evolves for Saturday into early next week is
still uncertain, with significant differences between the models
on the timing and strength of additional systems. At this time,
there is high confidence is highs near or below normal through at
least early next week and additional precip including mountain
snow. There is low confidence in how much total precip is
possible, whether precip will be mostly continuous or spilt into
multiple rounds, and how low snow levels will fall. Stay tuned to
the forecast, especially if you have plans to recreate in the
mountains and foothills.
Highs remain around 10-20 degrees above normal, in the 70s over
the west to 80s over the east, through Thursday. Friday into early
next week, temperatures cool with highs in the low 60s over the
west to low 70s over the east Friday falling to mostly 50s by
Sunday. By overnight Sunday into Monday morning, lows are likely
to be near to below freezing. See the table below for probabilities.
Archer
Frost    Freeze   Hard Freeze
Location     

NWS BYZ Office Area Forecast Discussion