Libby, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

174
FXUS65 KMSO 201932
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
132 PM MDT Fri Jun 20 2025

.DISCUSSION...

KEY MESSAGES:

-  Widespread precipitation with embedded thunderstorms this
   evening through the night.

-  Scattered precipitation chances through the weekend with much
   cooler temperatures.

-  Widespread accumulating mountain snow above 6,000ft with
   significant totals for Glacier N.P. and Flathead National
   Forest. Increased risk of hypothermia for backcountry users.

Radar and satellite imagery this afternoon portrays a large swath
of moisture streaming in from the southwest originating offshore
the northern California coast. Within this plume of moisture,
showers and thunderstorms have continued to increase in coverage
across much of the northern Rockies. Thunderstorms in southwestern
Montana today have a chance to grow to strong or severe status
with potential for hail up to 1" and wind gusts up to 40 mph. The
heaviest precipitation, for most, falls tonight as showers
continue late into the evening and overnight as the bulk of the
heaviest precipitation begins to shift northward toward the
international border as it wraps around the northernmost lobe of
this low pressure system.

Forecast precipitation amounts are relatively unchanged over the
last day. There is still a high (90%) chance for widespread
precipitation totals of at least 0.25" across the region, and a
50% chance of exceeding 1" of precipitation north and northeast of
Flathead Lake by Sunday evening.

The forecast also remains on track for what would be a sizable
snowfall in the Glacier Park region during the winter. While it
isn`t totally uncommon for June snow storms in Montana`s high
country, this is a fairly rare event given the duration and
intensity of the forecast impacts. Upgrades to Winter Storm
Warnings have been completed for this area due to anticipated
heavy wet snow generally above 5,000ft in this area. High-end
storm total snow amounts generally near a foot above 6,000ft with
the potential for isolated higher terrain areas to see up to 2
feet by Sunday night. With the snow also comes wind gusts up to 40
mph on exposed ridges and mountaintops as well as temperatures
near, and below, freezing which could be extremely hazardous to
any backcountry travelers caught by surprise or without adequate
shelter and/or clothing.

As the center of this closed low moves directly overhead through
the day on Saturday region-wide snow levels will drop to near
6,000ft. Scattered valley rain and mountain snow will continue
across northwestern Montana all day Saturday while valley
locations in west-central and southwestern Montana experience a
lull in precipitation through most of the day. During this time
frame, winds aloft becoming increasingly northerly as colder air
continues to spill into the Northern Rockies. For many other
mountain locations, Winter Weather Advisories have been issued
above 6,000ft where a couple inches of snow accumulation are
likely along with the aforementioned temperatures near, and below,
freezing as well as wind gusts up to 30 mph on exposed ridges and
mountaintops. This time of year, many rural seasonal roads have
been open for about a month, or more, leading to concerns with
folks who are deep in the backcountry on roads that are not
maintained for snow removal.

High temperatures Saturday and Sunday will be in the mid-to-upper
50`s (nearly 20 degrees cooler than normal for this time of
year). There is a possibility Monday morning for valley
temperatures in the mid to low-30s (depending on remnant cloud
cover). We will continue to assess the risk for any potential
frost advisories during this time period.

As the low exits, shower chances continue under northwest flow on
Monday (especially across northwestern Montana). Temperatures
gradually recover to near and above-normal through the early week
and the atmosphere begins to dry out.

&&

.AVIATION...Widespread showers and embedded isolated thunderstorms
this afternoon across the northern rockies. In southwestern
Montana and Lemhi county, strong to severe storms are possible
with outflow winds to 40 kt, frequent lightning, and small hail.
Widespread showers elsewhere will lead to mountain obscurations
and occasional MVFR ceilings all evening and into the overnight.

Steadier rain and terrain obscuration becomes more common late
tonight through Sunday across northwest Montana, especially near
KGPI, with snow likely above 5,000 ft. Valley sites will stay
rain-dominated, but visibility reductions are expected. A lull in
precipitation intensity and coverage is expected for most of
west-central and southwest Montana Saturday. Winds aloft also
become increasingly northerly during this period. Conditions
region-wide improve by late Sunday into Monday.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 2 AM Saturday to noon MDT Sunday
     for Bitterroot/Sapphire Mountains...Butte/Blackfoot
     Region...Potomac/Seeley Lake Region.

     Winter Storm Warning from 2 AM Saturday to noon MDT Sunday for
     West Glacier Region.

ID...Winter Weather Advisory from 2 AM MDT /1 AM PDT/ Saturday to
     noon MDT /11 AM PDT/ Sunday for Eastern Lemhi County...
     Southern Clearwater Mountains...Western Lemhi County.

&&

$$