Columbia Falls, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

398
FXUS65 KMSO 111822
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1222 PM MDT Wed Jun 11 2025

.DISCUSSION...

KEY MESSAGES:

- Potential for a few strong to severe thunderstorms/locally
  heavy rain threat in the afternoon hours and evening, mainly
  south of I-90.

- Warm through the rest of the week and into the weekend with
  daily chances for afternoon showers and storms.

- Chance for strong to severe storms again Friday.

Mid-high level cloud cover has been increasing today out ahead of
a shortwave trough tracking northeastward through southeast
Oregon and into central Idaho. In advance of this shortwave
feature, a cluster of light rain showers has been slowly pushing
to the north through Lemhi county and the southern Bitterroot
Valley extending as far east as Butte. Satellite and radar depicts
a much more stout squall line of thunderstorms producing frequent
lightning and gusty winds creeping northward toward Idaho and
Lemhi counties. Small hail and gusts to 35 mph have already been
reported earlier this morning as these storms pushed through the
Boise, Idaho area. Despite the cloud cover increasing,
temperatures have already warmed rapidly this morning into the mid
70s and low 80s by the noon hour (except where morning showers
have kept locations cooler into the 60s).

The latest CAM guidance has been persistent overnight and this
morning in having that line of thunderstorms associated with the
shortwave to move into southern Ravalli, Lemhi, Beaverhead, and
Deer Lodge/Silver Bow through this afternoon lasting until about
5 or 6 pm this evening. The strongest storms with this line will
be capable of producing wind gusts up to 60 mph as well as small
hail and isolated heavy rainfall due to modeled (and observed
vertical sounding from BOI this morning) PWATs around 1 inch. If
multiple rounds of storms train over the same location, there
could be concerns with localized small stream and creek responses
and/or debris and mud from burn scars. Most likely amounts under
heavier showers and storms max out around 0.50" of rainfall with a
60% chance to see rainfall amounts during any point this
afternoon to exceed 1/3" per hour.

Across the rest of the forecast area, anticipate scattered showers
and thunderstorms that could produce isolated wetting rains but
are more likely to produce gusty outflow winds up to 40 mph.

Over the next couple of days, southwesterly flow aloft will
remain in place due to a broad region of troughing parked just
offshore the Pacific Northwest. This will reinforce the warmer
than normal temperatures through the rest of the week and into the
weekend as well as the nearly-daily chance for convectively-forced
scattered afternoon showers and storms with daytime heating. By
Friday, an upper-level jet max in the exit region of the offshore
trough moves overhead increasing available shear and enhancing
synoptic lift to support an environment once again for strong to
severe thunderstorms during the afternoon and evening.

The breakdown of this pattern will be dependent on the offshore
trough and whether it flattens into a more zonal flow or if it
attempts to close off as it moves onshore by early next week. The
latest model guidance has backed off, yet again, on the latter
scenario with the "status quo" seemingly now the favored outcome
with near-zonal/west-southwesterly flow continuing for the near
future with a couple weak disturbances passing through at times.


&&

.AVIATION...A strong disturbance this afternoon has an increased
chance for showers and thunderstorms between 11/1900Z and
12/0100z. There is a potential for a few strong to severe
thunderstorms with erratic gusts up to 60 mph, hail and locally
heavy rainfall, mainly south of I-90 including near terminals KSMN
and KBTM, but cannot be ruled out at KMSO as well.


&&

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

$$