Libby, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

051
FXUS65 KMSO 200837
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
237 AM MDT Sun Jul 20 2025

.DISCUSSION...

KEY MESSAGES:

-  Isolated showers possible today

-  Well below normal high temperatures and increasing rain and
   storm potential on Monday

-  Widespread showers and thunderstorms on Tuesday

Water vapor satellite imagery shows moisture steadily increasing
from the west, signaling the beginning of a more unsettled
pattern. While much of the region will remain dry, high-resolution
models are beginning to show showers developing this afternoon
across north-central Idaho into west-central Montana. As a result,
a slight chance of showers has been added for this corridor.

Temperatures will remain below normal, similar to yesterday, but
winds are expected to be lighter than previous days in most
places.

Tonight though Monday:

A deepening trough over the Pacific Northwest will continue to
draw increasing moisture into north- central Idaho and western
Montana via a southwesterly jet. Precipitable water values (PWAT)
around 1.00 inch (well above seasonal normal) are expected to
enhance precipitation efficiency across the region.

Model guidance are showing agreement for light showers to develop
tonight across north- central Idaho and into west-central
Montana. Shower and thunderstorm activity will increase throughout
the day as the frontal boundary slowly advances into the region.
By the afternoon, scattered thunderstorms are expected to develop
Model agreement has improved regarding the placement of the front
and upper-level jet, resulting in a notable upward trend in
precipitation probabilities and amounts, particularly across
north-central Idaho into west-central Montana, where there is now
approximately a 50% chance of wetting rain (0.10") by Monday
evening. Rainfall amounts will generally be light to moderate, but
localized heavier totals are possible under slow-moving or
clustered cells.

Tuesday:

As the upper-level trough begins to eject northeast, stronger
synoptic lift will lead to more widespread showers and
thunderstorms, especially north of I-90 in western Montana. This
area will lie beneath the best overlap of moisture, lift, and jet
support. The NBM continues to show at least a 70% chance of
wetting rain across northwest Montana, and at least a 50% chance
of over 0.25", particularly around Glacier National Park and the
Flathead region.


Shower chances will linger into Wednesday as the trough exits the
region. A warming trend begins Thursday, with temperatures
rebounding to near seasonal normals by the end of the week.

&&

.AVIATION...A deepening trough over the Pacific Northwest and
increasing southwesterly flow will bring rising moisture and an
unsettled pattern to north-central Idaho and western Montana
through Tuesday. Today, water vapor imagery shows moisture
increasing from the west, and high-resolution models are beginning
to indicate isolated showers developing this afternoon from
north-central Idaho into west-central Montana. While most
terminals will remain VFR, brief reductions in visibility or
ceilings are possible in showers. Winds are forecast to be
lighter today in most places, and generally in the 15-25 kts
range.

By Monday, a frontal boundary and upper jet will increase lift and
instability, leading to showers and isolated thunderstorms.


&&

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

$$