357
FXUS65 KMSO 010818
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
218 AM MDT Wed May 1 2024

.DISCUSSION...An unsettled and cool pattern will continue the next
several days as an upper level trough remains over the Northern
Rockies. A few snow showers persist early this morning in
northwest Montana and north-central Idaho, watch for a few slick
spots, mainly at pass levels.

Multiple waves will rotate into northwest Montana through early
Thursday. This will keep persistent mountain snow showers going,
especially in the Glacier National Park region, and in the
vicinity of the Swan and Mission Ranges. There is a 90%
probability of at least 2 inches of snow accumulating on Highway 2
over Marias Pass, and a 65% probability of 4 inches, Wednesday
afternoon through Thursday morning. Once again, watch for snow
covered roadways near Marias Pass especially tonight through
early Thursday.

Elsewhere across the Northern Rockies, instability showers will
increase into this afternoon with gusty winds of 25-35 mph.

Scattered daily showers are expected Thursday and to a lesser
extent Friday as the general trough persists. Models continue to
take the main forcing of a secondary low across eastern Oregon
into southern Idaho. This leaves the Northern Rockies with mainly
instability driven showers, most widespread in the
afternoon/evening hours but impacts will be limited to brief
nuisance showers.

At this point, Saturday morning/afternoon is a mostly shower-free
period with daytime temperatures back to seasonable levels (60s in
the valleys).

Ensemble clusters support an active weather pattern under a
general upper level trough with intermittent showers and cooler
temperatures Sunday (May 5th) through the first full week of May.
Many details are still uncertain but snow levels will likely drop
to at least pass levels once again with a 40% probability of at
least 2 inches of snow Monday/Tuesday for passes along the ID/MT
border. Wetting rain (at least 0.10 inch) chances are near 80%
for most places as well.



&&

.AVIATION...Multiple waves will rotate counter-clockwise around
the stationary upper level low over southern Alberta and
Saskatchewan into northwest Montana. This will keep persistent
mountain snow showers going with reduced ceilings, especially in
the Glacier National Park region, and in the vicinity of the Swan
and Mission Ranges through early Thursday. The remainder of the
region will experience an uptick in afternoon showers with gusty
winds of 20-30 kts.



&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 4 PM Wednesday to 9 AM MDT Thursday
     for West Glacier Region.

ID...None.
&&

$$