Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 162033

Area Forecast Discussion
National Weather Service Missoula MT
233 PM MDT Fri Mar 16 2018

.DISCUSSION...A southwesterly flow has led to a very nice spring
day across the Northern Rockies, with many locations seeing above
normal temperatures for this time of the year.

Conditions will begin to change for some starting tomorrow
morning, as our next weather disturbance develops and approaches
from the southwest. Widespread snow is still expected to develop
by tomorrow morning for Lemhi county and then for north-central
Idaho by the afternoon and early evening. As the low moves north
over west-central and southwestern Montana Saturday night, rain
will transition to snow in those areas. Most impacts to the roads
due to snow will be in the overnight hours Saturday, and early
Sunday morning. We still expect the valleys in Montana, along and
south of the I-90 corridor and north-central Idaho, to receive
anywhere from 1 to 4 inches of snow by Sunday morning. Areas from
Hamilton south to Darby in Montana, have a chance of seeing
slightly higher amounts. The mountains and mountain passes could
see up to a foot of new snow. A number of Winter Weather
Advisories have been issued, and can see the details by visiting

Scattered snow showers will linger through the day on Sunday, with
a northwesterly flow interacting with additional wrap around
moisture from the exiting low. This will be when northwestern
Montana will have a chance for light snow accumulations.

Lingering showers under unsettled northwesterly flow will continue
Monday into Tuesday. High pressure will rebuild Tuesday night,
allowing for a very pleasant spring day on Wednesday for all of
the Northern Rockies. Our next organized weather system will
enter off the Pacific Coast on Thursday, spreading moisture across
north central Idaho and western Montana through the end of the
week. Precipitation looks to begin as rain up to around 5000 feet,
with a cold front causing snow levels to drop to roughly 2000 feet
by the weekend.


.AVIATION...Pleasant conditions are expected to continue for the
rest of the day across the Northern Rockies. Mountain snow showers
are expected to develop for areas south and west of the I-90
Corridor this afternoon, though they are not expected to impact
area aviation terminals. Snow will likely impact KSMN by 12Z
Saturday morning, then impacting KMSO and KBTM later Saturday


MT...Winter Weather Advisory from 3 PM Saturday to noon MDT Sunday
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

     Winter Weather Advisory from 9 PM Saturday to noon MDT Sunday
     Missoula/Bitterroot Valleys.

ID...Winter Weather Advisory from 8 PM Saturday to 11 AM PDT Sunday
     ABOVE 3000 FEET for the Lower Hells Canyon/Salmon River
     Region...Northern Clearwater Mountains...
     Orofino/Grangeville Region.

     Winter Weather Advisory from 2 PM Saturday to 11 AM PDT Sunday
     ABOVE 3000 FEET for the Southern Clearwater Mountains.

     Winter Weather Advisory from 6 AM Saturday to 6 AM MDT Sunday
     Eastern Lemhi County...Western Lemhi County.


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