130 
FXUS65 KMSO 272121
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
221 PM MST Fri Dec 27 2019

.DISCUSSION...A weak weather disturbance will continue to produce
areas of very light snow over north central Idaho, southwest
Montana and parts of northern Lemhi County tonight. Local slick
road impacts could be felt, especially Grangeville, Bitterroots, 
Bitteroot Valley and Sapphires tonight. 

Weak high pressure and generally dry air mass will return
Saturday.

The next weather system will slide southward across north central
Idaho and western Montana late Saturday night and Sunday. This
weather system should produce a bit more snow accumulation and
more widespread light snow over west central Montana and north 
central Idaho than the current weather system. Local slick road
impacts are expected Sunday morning along the I-90 corridor and
southward across western Montana and north central Idaho. 

High pressure and a drier air mass is expected to return Sunday
night through Monday.

A change to a significantly moist northwest flow is possible late
Tuesday into the end of next week. Some of the model guidance
suggest periods of moderate to heavy mountain snow is possible
with a mixed precipitation for the valleys. There remains enough 
uncertainty not to pinpoint amounts or how cold/mild it could be.
However, at present time we slightly favor the cooler ECMWF 
solution later next week because of upstream influences favoring 
such a cooler/moist pattern. 

&&

.AVIATION...Northerly flow will produce areas of light snow 
across north central Idaho and mainly southwest Montana tonight. 
Mountain obscurations can be expected, especially Bitterroots, 
Sapphires and Clearwater Mountains. Occasional lower ceilings and 
visibilities can be expected at KMSO, and possibly KSMN or KBTM. 
Partial clearing across far northwest Montana may allow areas of 
low stratus of fog to develop later tonight with KGPI the main 
terminal impacted. 

&&

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

$$