Butte-Silver Bow, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

697
FXUS65 KMSO 220950
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
250 AM MST Sun Dec 22 2024

.DISCUSSION...

KEY MESSAGES:

-  Risk for freezing rain on Monday across portions of northwest
   and west-central Montana valleys

-  Continued unsettled weather throughout the holiday week

-  Lowering snow levels for the end of the week

A quasi-stationary low pressure circulation is parked over the
Aleutian Islands, sending shortwave troughs onshore over the
Pacific Northwest. The first disturbance is exiting the Northern
Rockies early this morning, while the next is making its way
onshore.

This next disturbance will arrive in the Northern Rockies tonight
into Monday, once again bringing light precipitation. Southwesterly
flow aloft will result in temperatures conducive to light
mountain snow and a wintry mix in the valleys. There will be a
chance for periods of light freezing rain on Monday morning,
primarily focused on the Bitterroot and Flathead valleys.

Another round will arrive on Tuesday afternoon. Again,
temperatures will stay more conducive to rain on the valley floors
as snow levels start out in the neighborhood of 4000 feet.

This active weather pattern will continue over the Northern
Rockies from Christmas onward as the Aleutian Low keeps spinning,
sending a steady fetch of moisture into the Northern Rockies under
a favorable position of the upper level jet. The mountains along
the Montana/Idaho border could have fairly steady snow through
next weekend, which could cause some impacts to holiday travel.
Snow levels will lower by Thursday, which should allow snow to
fall in the valleys.


&&

.AVIATION...Precipitation will decrease today as one disturbance
departs and another approaches. Showers will linger this morning,
especially over the mountains where precipitation will be capable
of obscuring terrain. There looks to be enough of a gradient this
morning to keep fog out of the TAFs. Overcast skies will persist.
Expect another round of precipitation tonight as the next
disturbance arrives.

&&

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

$$