Butte-Silver Bow, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

909
FXUS65 KMSO 141953
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
150 PM MDT Wed May 14 2025

.DISCUSSION...

KEY MESSAGES:

- Thursday morning rain for northwest Montana, with light
  mountain snow above 6,000 feet.

- Unsettled pattern persists.

Showers and an embedded thunderstorm will continue in the Northern
Rockies as a mid- level circulation slowly moves off the east.
While lightning is not expected to be prolific, a few strikes here
and there will be possible especially in higher terrain.

A weak open wave will slide down the backside of the trough over
the region overnight. Increasing showers in northwest MT
especially along the Continental Divide. A few inches of wet snow
will be possible by Thursday morning, mainly in elevations that
still have snow on the ground, IE Logan Pass, Glacier National
Park.

Friday the next open wave breaks off a digging Pacific trough and
brings more light precipitation to the region.

The trough will continue to dig into Eastern Oregon and Northern
Nevada by Saturday and bring a short lull to the current pattern.
In addition, southerly flow will allow for a slight warm up.
Unfortunately, cloud cover throughout the day will moderate
warming keeping temperatures seasonable, roughly mid-60s in
Western MT and low 70s north-central ID.

A mid-level low slides into the newly formed trough on Sunday,
reigniting shower activity Sunday. Cooler temperatures will lower
instability, but there is at least a 20% chance in NW MT and 50-70%
chance elsewhere of receiving 0.25" of precipitation by Monday
morning.

The trend for unsettled and cooler weather will continue through
at least Wednesday. Then the model ensembles suggest a 70%
probability of a ridge of high pressure developing, with at least
the ECWMF deterministic model suggesting `summer-like` warmth.
The remaining 30% of models fall into the `Groundhog Day`
solution, you guessed it, unsettled and cooler.


&&

.AVIATION...Lower ceilings and mountain obscuration are expected
today from Lemhi County to southwest Montana due to wrap- around
rain and snow. Afternoon showers and thunderstorms are expected
across northwest and west-central Montana, with potential impacts
including: lightning, gusty winds to 20 knots, brief heavy rain,
pea-sized hail or graupel.

&&

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

$$