295 
FXUS65 KMSO 311034
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
434 AM MDT Thu Oct 31 2013

...OCCASIONAL SNOW OVER MOUNTAIN PASSES THROUGH FRIDAY MORNING...
...VALLEY SNOWFALL POSSIBLE SUNDAY MORNING...

.DISCUSSION...

A weakening storm system will approach the Northern Rockies from
the northwest today, bringing some light snow to mountain pass
elevations and above. Snowfall will be periodic and last through
Friday morning. Rapidly changing road conditions and reduced
visibility are possible over area mountain passes during this
time, including Lolo, Lookout, Lost Trail, and Marias Passes. High
elevation snow showers will continue Friday morning through
Saturday morning, however snow impact is anticipated to be minimal.

By midday Saturday, a vigorous Pacific storm system and its
associated surface cold front will approach the Northern Rockies.
The passing of the surface cold front will be fairly dramatic,
accompanied by gusty winds and brief, intense rain/snow showers.
The more significant weather-related impact of snow over mountain
passes will occur after the cold front passes and continue through
Monday. Hazardous driving conditions due to snow-covered roadways
and reduced visibility will be present at times. Snow levels will
drop to valley elevations by Sunday morning. Despite snowfall
expectations of less than one inch for elevations below 4000 feet,
a sudden change in road conditions is possible Sunday morning for
the Missoula, Bitterroot, Flathead, and Mission valleys.

Light snow potential remains in the forecast through Wednesday,
with a cold core of air persisting over the Northern Rockies.
Model guidance agree that brief high pressure will develop around
Thursday, ahead of the next vigorous Pacific storm system. The
evolution of this next Pacific system that is more than a week
away appears awfully similar to the system that will precede it,
including the impacts of snowy roads and low visibility.
Confidence in the long-term pattern is bolstered by the remarkable
agreement among the model guidance through the day-8 forecast and
beyond.

&&

.AVIATION...A weak weather system will bring scattered rain/snow
showers throughout the day today and will obscure the area
terrain. All TAF sites will see minimal impact to aviation
operations as these showers will be brief and short lived. KGPI
will have the best chances for brief showers and lower ceilings
through the morning and early evening hours.

&&

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

$$

Zumpfe
Aviation...Kino

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