733
FXUS65 KMSO 191947
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
147 PM MDT Sat Apr 19 2025

.DISCUSSION...

KEY MESSAGES:

- Mostly unsettled weather with valley rain, mountain snow, and
  gusty west winds today and Sunday

- Snow over mountain passes on Monday morning

- Unsettled spring-like weather will continue into the middle of
  next week with a warm-up later in the week


Radar returns this afternoon are indicating a southwest to
northeast oriented line of showers moving across the Northern
Rockies. These showers are inline with a weak shortwave trough and
associated cold front. Increasing clouds, widespread showers, and
increased westerly winds will accompany this system through this
evening. Precipitation will stay in the form of rain below about
6000 feet.

Moist westerly flow will keep some showers in the forecast for
Sunday. The best chances for precipitation will be across
northwest Montana and north-central Idaho in the morning,
spreading southward across the remainder of the Northern Rockies
in the afternoon. Snow levels will fall to about 5000 feet for
northwest Montana and the Clearwater range in Idaho. By Sunday
night, a trough of low pressures will deepen over the Northern
Rockies, bringing more widespread precipitation in time for the
Monday morning commute. This system will have some colder air
associated with it, so expect snow levels coming down to about
4000 feet for northwest Montana and north-central Idaho. Warm road
temperatures should keep travel impacts from snow out of the
valley locations and limited to the mountain passes. Lookout,
Lolo, Lost Trail, and Marias passes could all pick up a few inches
of snow on Monday morning. The position of an upper level jet
streak and an unstable atmosphere will be conducive to windy
conditions at the surface on Monday afternoon and evening.

Ensemble model solutions are showing an unsettled pattern of
westerly flow with some embedded shower activity, mostly for
northwest Montana and the Clearwater range in Idaho, through
Tuesday. Temperatures for the week will be mostly seasonable, with
Thursday being the warmest. Low pressure is the most likely
solution for next weekend, though timing and amplitude of the
trough are still very much in question.

&&

.AVIATION...A line of showers, visible on radar imagery, will
continue moving through north-central Idaho and western Montana
this afternoon and evening. These showers will bring lowered
ceilings, reduced visibility, and gusty winds of 15-25 knots.
High-resolution models indicate that winds will gradually decrease
this evening, though isolated showers may persist overnight,
particularly in northwest Montana. By Sunday, a trough is expected
to dig into the Pacific Northwest, bringing increasing westerly
winds along with showers and isolated thunderstorms by the
afternoon.

&&

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

$$