FXUS65 KMSO 040748
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1248 AM MST Wed Dec 4 2024

.DISCUSSION...


KEY MESSAGES:

-  Ridge of high pressure through end of the week causing stable
   conditions with valley fog and stratus

-  Cold front this weekend with wintry mix potential to start,
   then light valley snow accumulations late Sunday into Monday 
   morning

High pressure ridging continues into Friday with low stratus and
freezing fog across the valleys of northwest Montana and north-
central Idaho. Gradual expansion of the fog/stratus is likely for
other valleys of western Montana during overnight periods. Travelers 
should beware of reduced visibilities and a few slick spots 
associated with dense freezing fog. 

The feature to end the week has trended slower, with moisture not
increasing until Saturday morning. Areas with stratus and 
established cold pools, mainly high elevation valleys of Idaho 
County and northwest MT, may begin with light freezing rain or 
light snow but snow levels are expected to quickly climb above 
6000 feet and remain there through midnight Saturday. Sunday, as a
cold front pushes through the region snow levels lower into 
valleys and a transition to light snow for all is expected, except
for the Lower Hells Canyon. Currently, mountains passes such as 
Lookout, Lolo, and Marias have 25th to 75th percentile totals of 3
to 7 inches. Valleys have a 60 to 70% chance of receiving a trace
or greater but unlikely greater than 1 inch except higher valleys
of Idaho County. Watch for occasional slick roads Saturday night 
through Monday morning, mainly on passes. 

General model consensus for much of next week is northwest flow
with a round or two of precipitation. Details are scarce as models
continue to struggle with the placement of the ridge west of the
Northern Rockies but at least some wintry precipitation is likely.



&&

.AVIATION...Stable conditions continue the next several days under
a ridge of high pressure. Fog and low stratus has been present 
across many valleys of north central Idaho and across northwest 
Montana. The fog and stratus will likely erode somewhat each 
afternoon then increase in coverage and thickness each night. Fog 
and low stratus coverage may expand into the Missoula Valley, 
bringing a few hours of lowered visibility and ceiling today,
perhaps extended hours on Thursday morning. The remainder of the 
region will have increasing potential for visibility reductions 
from localized fog each morning through Friday.

&&

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

$$