768
FXUS65 KMSO 281835
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1235 PM MDT Sun Apr 28 2024

.DISCUSSION...A series of troughs moving in from the west coast
will move across the region to start the week. These systems are
considerably cooler than the recent systems we`ve have come
through, so snow levels will drop much lower.

The first system will come through tonight, and we`ve issued
winter weather advisories for central Idaho and the Bitterroot and
Sapphire Mountains in western Montana above 5000 feet and in Lemhi
County above 6000 ft. Snow will fall at lower elevations as well,
it is just not expected to be enough of an impact to warrant an
advisory. Missoula, the Bitteroot Valley, and Salmon Idaho all
have a 20 percent or less chance of picking up some snow Monday.
In the valleys, it will generally be less than an inch of snow and
would likely only accumulate on the grass and elevated surfaces
and melting off quickly on the roads.

The second system will dive south of our region into central
Idaho, but as it does so it will pull some wrap around moisture
from the first system into our area from the East. This will
impact northwest Montana, especially Glacier National Park on
Wednesday. There`s a 45 percent chance of 4 inches or more of snow
affecting Marias pass with this system. Logan Pass and the back
country will get considerably more snow with around a 20 percent
chance of a foot or more along the Continental Divide there. Most
of the uncertainty with the snow forecast for that system is
related to the tracks of both of the interacting low pressure
systems and how they interact. If that results in northwest flow,
the higher elevations west of the Continental Divide could pick up
quite a lot so snow, however if it results in northeast flow then
most of the snow will be east of the divide.

Ensembles and long term models agree well on another system
impacting the region on Friday. And in general, ensembles show an
active Spring weather pattern for the next couple of weeks.



&&

.AVIATION...VFR conditions with mid level ceilings are expected
today with moist, westerly flow aloft. Another trough is
approaching the region for tonight which will bring lower ceilings
and showers for Monday. Snow levels continue to fall, and while
snow is possible at area terminals, the amounts expected in the
valleys combined with the high solar angle and warm ground
temperatures make snow accumulation very unlikely.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from midnight tonight to 6 PM MDT Monday
     for Bitterroot/Sapphire Mountains.

ID...Winter Weather Advisory from midnight MDT /11 PM PDT/ tonight to
     6 PM MDT /5 PM PDT/ Monday for Eastern Lemhi County...
     Northern Clearwater Mountains...Southern Clearwater
     Mountains...Western Lemhi County.

&&

$$