Columbia Falls, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

717
FXUS65 KMSO 030950
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
250 AM MST Tue Dec 3 2024

.DISCUSSION...


KEY MESSAGES:

-  Ridge of high pressure through mid week causing stable
conditions with valley fog and stratus.

-  Pattern change at the end of the week into the weekend.

The ridge of high pressure continues over the Northern Rockies
through Thursday. Latest satellite imagery is showing that fog
and low stratus has settled over most valleys of northwest
Montana and along the Clearwater River & Dworshak Reservoir in
north central Idaho. The fog and stratus is anticipated to erode
somewhat each afternoon but increase in coverage and thickness each
night through at least mid week. Travelers should beware of
reduced visibilities and a few slick spots associated with dense
freezing fog.

A very subtle feature is expected to slide over northwest Montana
today. This feature has the potential to interact with the
stratus cloud deck to cause localized flurries and/or freezing
drizzle, but impacts should be minimal.

The models continue to advertise that a weak plume of moisture
moves into north central Idaho and northwest Montana Thursday
night into Friday. The atmospheric profile for northwest Montana
shows that precipitation should stay mainly snow. While north
central Idaho has a better chance of having rain in the valleys
and snow in the higher terrain. Overall, precipitation amounts
look to remain very light.

A more robust push of moisture is expected Saturday. The
disturbance associated with this moisture pushes in warmer air
raising snow levels to around 6000-7000 feet. Strong valley
inversions across northwest Montana could create conditions
favorable for patchy freezing rain by Saturday morning. The latest
guidance is showing a 10-30% chance of freezing rain with the
highest probability being around the Libby/Troy/Yaak region.

A cold front is expected to push through the region on Saturday
night into Sunday. This front will drop snow levels down to around
4000 feet by Sunday morning. The lingering trough of low pressure
should continue to lower the snow levels down to valley floors by
Monday morning. The mountain passes should anticipate a couple of
inches of new snow accumulations, along with occasional slick
roads Saturday night through Monday morning.



&&

.AVIATION...The ridge of high pressure will strengthen over the
next couple of days. Fog and low stratus is in place across many
valleys of north central Idaho up into northwest Montana. The fog
and stratus will likely erode somewhat each afternoon then
increase in coverage and thickness each night. KGPI is
impacted by fog/mist currently and is expected to shift to a low
stratus cloud deck later this morning. The remainder of the
terminals will have the potential for the visibility reductions in
localized fog.

&&

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

$$