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fxus65 kmso 211023 

Area forecast discussion
National Weather Service Missoula Montana
323 am MST Tue Feb 21 2017

Discussion...another surge of moisture will work northward across
the region this morning and will settle over northwest Montana
during the afternoon hours. The result will be a period of light
snow for valley floors followed by a changeover to rain later in
the morning, one exception will be the lower elevations of
northwest Montana which may remain snow. Changeable and
potentially hazardous Road conditions are anticipated as a result
of the snow/rain mix in valley locations. Mountain passes will see
several rounds of snowfall with alternating periods of wet-snow
packed-back to wet conditions. Windy weather is expected across
southwest Montana and in Lemhi County today, beware of strong
cross winds and occasional snow showers. Also, there remains a
potential for a few debris flows along susceptible travel
corridors (such as Hwy 12 in idaho) with ponding on area roadways.

Precipitation will become showery again on Tuesday night with a
cold front passage dropping snow levels to valley floors once
again. Although valley snow accumulations should remain light,
slippery roadways are certainly possible, while mountain passes
will continue to see winter driving conditions at times into
Wednesday morning.

Showers will slowly start to taper off Wednesday morning, and the
daytime will be the last "mild" temperature day before a much
colder air mass starts to sweep into the region by mid to late
Wednesday. A cool, showery regime will continue Thursday into the
early weekend. Although snow showers will be scattered with only
minimal accumulations expected, roads can easily become icy/snowy
as Max temperatures remain generally below freezing and minimum
temperatures drop down to the several degrees below
zero closer to the Continental Divide.

By late Sunday into early next week, enhanced moisture may be
pulled into the area from the southwest which would meet the cold
Canadian air pushing down from the north. Forecast confidence
remains low on location and how intense precipitation will become,
but a period of widespread precipitation may be in store for
portions of the northern rockies through early Tuesday.


Aviation...patchy fog will once again be possible early this
morning (mainly for kmso and kgpi) ahead of another round of
rain/snow. Reduced visibility and lowered ceilings will be common
at terminal sites, along with mountain obscurations as
precipitation works northward across the region. Precipitation
will become more showery this afternoon with a few intense
showers capable of gusty winds and a lightning strike or two.
Gradient winds will also be breezy for kbtm and ksmn today with
gust of 25 to 30 kt possible.


Mso watches/warnings/advisories...
Montana...Winter Weather Advisory until 11 am MST Wednesday
Bitterroot/Sapphire Mountains...Lower Clark Fork region.

Winter Weather Advisory until 11 am MST this morning
Missoula/Bitterroot valleys.

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