Apgar, Montana Weather Forecast Discussion

850
FXUS65 KMSO 170643
AFDMSO
Area Forecast Discussion
National Weather Service Missoula MT
1243 AM MDT Wed Sep 17 2025
.DISCUSSION...
KEY MESSAGES:
- Cool mornings with patchy frost and fog through Friday morning,
  especially in higher valleys, before giving way to warm, sunny
  afternoons
- Shower/thunderstorm chances return later this weekend
High pressure will bring an extended dry period for the latter half
of the work week. Afternoons will be warm (5-10 degrees above
normal) and mornings will be cool under mostly clear skies. Patchy
frost formation is likely for higher elevations valleys along the
Divide. Additionally, patchy valley fog will exist in the
mornings.
Models show a weak disturbance flattening the ridge on Friday allowing
for the potential of a few light showers. A stronger disturbance
on Sunday looks to bring more widespread shower/thunderstorm
coverage, with high temperatures dropping back to seasonable
levels and westerly winds picking up.
There is decent agreement (80% of ensemble clusters) on brief
ridging (warming/drying) again early next week (Sept 22-23).
The pattern looks progressive with another trough over the
Pacific Northwest by Sept 24-25th but the details are limited.
&&
.AVIATION...
Mostly clear skies and light winds will create favorable
conditions for the formation of patchy fog or localized low
stratus this morning. This may lead to a period of MVFR or even
brief IFR conditions between 10Z and 14Z today. Otherwise, VFR
conditions will occur the next several days under high pressure
ridging. Winds will be light under a weak easterly gradient today.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
$$

NWS MSO Office Area Forecast Discussion