648
FXUS65 KMSO 300737
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
137 AM MDT Sun Aug 30 2026

.DISCUSSION...

KEY MESSAGES:

- Elevated post-frontal winds creating choppy conditions on
  Flathead Lake through early Sunday.

- Unseasonably cold temperatures (10 to 15 degrees below
  average) bringing high- elevation valley frost Sunday and Monday
  mornings.

- Brief warm-up early next week followed by another
  cool, active trough late next week.


Today through Tuesday: Early morning showers across southwest
Montana will taper off, with primary weather impacts shifting to
northwest Montana today as moisture wraps around an upper-level
low in southern Alberta. Precipitation will remain light, with
valley liquid totals under 0.10 inches and mountain amounts near
0.25 inches; a light dusting of snow is expected on peaks above
7,000 feet. Westerly winds will gust 15 to 25 mph today across the
whole Northern Rockies before relaxing at sunset, causing
localized choppy conditions on regional lakes.

Clearing skies and drying air tonight will promote strong
radiational cooling. Widespread frost is expected in high-
elevation valleys (e.g., Dixie, Seeley Lake, Butte), with
localized light frost reaching lower elevation spots such as
Stevensville and the western Missoula Valley by Monday morning.
Transitory ridging will bring warm, dry conditions Monday into
Tuesday, pushing valley highs back into the 80s.

Tuesday Afternoon through Late Week: By Tuesday afternoon and
evening, increasing mid-level moisture and weak instability will
yield scattered showers and isolated thunderstorms moving south to
north. High cloud bases and dry low-level air will yield
inverted-V thermodynamic profiles, elevating the potential for
strong, gusty outflow winds. Activity will expand on Wednesday as
an incoming shortwave disturbance interacts with the moisture
plume. Wetting rain (> 0.10 inches) probabilities increase to
50-70% across much of the Northern Rockies. Ensemble guidance
shows strong clustering (80-90% confidence) around a lingering
Pacific Northwest trough late week, preserving an active weather
regime with temperatures slightly below seasonal averages.



&&

.AVIATION...Early morning showers will impact southwest Montana; otherwise,
primary aviation impacts today will focus across northwest
Montana as clouds and precipitation wrap around an upper-level low
over southern Alberta. VFR conditions will prevail across most
valley terminals, though localized MVFR ceilings remain possible
in passing showers. Periodic mountain obscuration will affect
higher terrain, with snow levels dropping to 7,000 ft MSL and
light snow accumulating on high peaks. Westerly surface winds will
become gusty this afternoon, reaching 15-25 kt before decoupling
near sunset.

Brief ridging builds in Monday for VFR conditions and light,
diurnally driven winds.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$