Area Forecast Discussion 
FXUS65 KMSO 162028
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE Missoula MT
228 PM MDT SAT Mar 16 2013
...PRECIPITATION changing to all snow overnight tonight...
...Colder with snow showers and breezy west winds Sunday...
.DISCUSSION...
Tonight through Sunday Night...A vigorous cold frontal system will
be moving through Northern Idaho and western Montana tonight.
PRECIPITATION in the form of mountain snow and valley rain showers
will be changing to all snow as the ATMOSPHERE cools and snow
levels crash to the valley floor. The influx of moist, unstable
and colder air will continue into Sunday night. Greatest snow
accumulations and biggest travel issues will target the area
mountain passes. Valley locations will also see snow, but
accumulations will vary greatly, plus there will be some melting
on the roadways while snow is underway. That said, valleys along
the continental divide zones will see several inches of new snow
by Sunday Night and have been included in Winter Weather
Advisories. Westerly winds will increase with the passage of the
COLD FRONT tonight, becoming quite gusty Sunday as cold air
continues to flush in from the west.
A northwest FLOW on Monday will bring a chance of snow to western
Montana and north central Idaho, temperatures will be cool enough
that some snow accumulation is expected. Tuesday, a weak RIDGE will
move in from the west, bringing drying conditions and a slow warming
trend. Wednesday looks to be the warmest day of next week, but with
a change coming later in the day as another Pacific weather system
moves into the region. This TROUGH will lower snow levels to most
valley floors. Into next weekend, another RIDGE looks to build near
the west coast. The models are struggling with the strength and
MOISTURE streaming through the RIDGE into the Northern Rockies so
climatological POPS and temperatures remain.
&&
.AVIATION...An UPPER LEVEL TROUGH and surface COLD FRONT will be
impacting the Northern Rockies region tonight through Sunday.
The COLD FRONT will pass through the area tonight which will
increase PRECIPITATION and westerly winds. Expect cloud bases to
lower and higher terrain becoming obscured by this evening.
PRECIPITATION will be changing to all snow reducing visibilities
at times. A cold upper TROUGH with a moist UNSTABLE AIR mass
will reside over the area Sunday. Numerous snow showers can be
expected through Sunday.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY from Midnight tonight to Midnight MDT
Sunday Night ABOVE 6000 FEET FOR THE Butte/Blackfoot Region.
WINTER WEATHER ADVISORY from 9 PM this evening to Midnight MDT
Sunday Night for Lolo Pass and Lost Trail Pass IN THE
Bitterroot/Sapphire Mountains.
WINTER WEATHER ADVISORY from 6 PM this evening to Midnight MDT
Sunday Night for I-90 Lookout Pass to Haugan IN THE Lower
Clark Fork Region.
WINTER WEATHER ADVISORY from Midnight tonight to Midnight MDT
Sunday Night Potomac/Seeley Lake Region...West Glacier
Region.
ID...WINTER WEATHER ADVISORY from 9 PM MDT /8 PM PDT/ this evening to
Midnight MDT /11 PM PDT/ Sunday Night for Lolo Pass and
Lost Trail Pass IN THE Eastern Lemhi County...Southern
Clearwater Mountains.
&&
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