744
FXUS65 KMSO 280930
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
330 AM MDT Thu Aug 28 2025

.DISCUSSION...

KEY MESSAGES:

- Locally dense fog may reduce visibility in the valleys of
  north-central Idaho this morning.

- Widespread showers and thunderstorms will be capable of rainfall
  rates approaching 0.75 inch per hour, with the greatest
  potential in southwest Montana this afternoon.

- Warming and drying anticipated for the weekend.

This Morning: Locally dense fog

Locally dense fog is possible this morning in the valleys of
north-central Idaho, where wildfire smoke is combining with
abundant low-level moisture from recent rain. Visibility may drop
below a quarter-mile, creating hazardous travel conditions. If you
encounter dense fog while driving, slow down, use low-beam
headlights, and increase the distance between your vehicle and the
one ahead.

Today: Widespread Showers and Locally Heavy Rain

A slow-moving low-pressure system will bring widespread showers to western
Montana and north-central Idaho today. The atmosphere contains nearly 200%
of its normal moisture for this time of year. This means any stronger
showers or thunderstorms that develop will be capable of producing heavy
rainfall, with rates approaching 1.00 inch per hour. While extensive cloud
cover may limit overall thunderstorm development, the highest potential for
these heavy downpours appears to be in a corridor from southwest Montana
northward toward Missoula.

Friday through the Weekend: Drying and Warming Trend

The weather pattern will improve for Friday and the weekend as the storm
system departs and high pressure builds. This will bring a warming and
drying trend with temperatures returning to normal. However, enough
lingering moisture will remain for a chance of isolated afternoon showers
and thunderstorms, mainly across northwest Montana on Friday and near the
Continental Divide through the weekend.

Early Next Week: Uncertain Forecast

Forecast confidence decreases for the start of next week. Computer models
show significant disagreement on the track and timing of the next
approaching storm system, leading to an uncertain forecast for Monday and
beyond.


&&

.AVIATION...Widespread showers exist across much of western
Montana and north central Idaho this morning, causing widespread
lowered ceilings and obscurations of the higher terrain. Locally
dense fog is possible in valleys of north central Idaho due to
the combination of saturated low levels due to ongoing rainfall
and smoke from area wildfires. Forecast models indicate
precipitation will become more convective this afternoon, with
lightning and very heavy rainfall rates being the main concern.
The highest probability for lightning exists for KBTM (30 percent
chance by 28/2300z) and KMSO (20 percent chance by 28/2300z).

&&

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

$$