948
FXUS65 KMSO 120715
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
115 AM MDT Mon Oct 12 2026

.DISCUSSION...

KEY MESSAGES:

- Hard freeze coming for the mornings.

- Valley fog and stratus will be common early this week.

- A warming and drying trend this week.

- Another cold and cold front on the way for early next week.

The winter storm is winding down this morning as the upper level
low over the Pacific northwest is migrating south today. Expect
cool, cloudy weather today as both the moisture source and the
source of the cold air are cut off from the region today. That
being said, there`s quite a bit of cold air already in our area
from this storm.

Due to the cold air mass in place, increasing stability, and a
drier air mass aloft moving, expect some very cold, foggy mornings
ahead. The next few mornings will be a battle between how much it
can cool off at night, and how much fog and stratus can form in
the valleys to keep things warmer. In any case, there`s plenty of
potential for a hard freeze the next few mornings with
temperatures in the low to mid 20s for much of western Montana.
However, due to the recent moisture, as it gets cold at night that
will be limited by fog formation. If the fog forms, temperatures
in the mid to upper 20s are more likely in the mornings, but if
there are breaks in the fog, especially in the high elevation
valleys, then it will get quite cold quickly.

Through the week a ridge will build back in over the region. This
will cause more stable conditions, limiting how quickly fog can
burn off in western Montana. Central Idaho and far northwest
Montana picked up far less moisture from this recent storm, so
that will be less of an impact there. However, the building ridge
will cause temperatures to rise to above average for this time of
year by the end of the week.

Ensembles are starting to agree on another cold front for early
next week, so the warmer, drier weather at the end of the week
will only last a few days. So far ensembles are showing less
potential for moisture with the next front, especially if it comes
through as an open wave vs a closed low like this last one. So it
wont` be a repeat of this system, but will probably come with more
westerly winds, some precipitation, and a good cool down.

&&

.AVIATION...Ceilings and visibility will be a challenge today.
Many areas have received a lot of moisture recently, and as the
upper level low over the Pacific Northwest migrates south a ridge
starts to build over the region today. So early today the region
will battle low clouds and fog from all the recent moisture, then
with the increasing stability overnight and latent moisture, fog
will continue to be a problem in many area valleys for the next
few days.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 6 AM MDT early this morning for
     Bitterroot/Sapphire Mountains...Potomac/Seeley Lake
     Region...West Glacier Region.

     Lake Wind Advisory until 6 AM MDT early this morning for
     Flathead/Mission Valleys.

     Winter Storm Warning until 6 AM MDT early this morning for
     Butte/Blackfoot Region.

ID...None.
&&

$$