Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 192023

Area Forecast Discussion
National Weather Service Missoula MT
223 PM MDT Mon Mar 19 2018

.DISCUSSION...A moist, cool, and unstable atmosphere will linger
over north central Idaho and western Montana this evening and
tonight. The showers should concentrate mostly over the southern
Clearwaters and eastward across the Lost Trail Pass area with
snow covered roads a possibility tonight. Another area that should
see a higher concentration of showers is from Libby and Troy
eastward across Glacier National Park.

The cool and unstable atmosphere will linger Tuesday. However,
the air mass should slowly dry...meaning a continued trend towards
less showers.

Weak high pressure is expected to return Wednesday with
temperatures moderating to at least a few degrees above normal.
However, some moisture will continue to feed into north central
Idaho with isolated showers.

A rather strong cold front will shift across north central Idaho
late Thursday and into western Montana Thursday night. Initially
Thursday, much of the region will continue to be on the warmer
side of the front. As the cold front approaches, it should become
breezy in most areas. The atmosphere may become unstable enough
along the cold front late Thursday to support a few heavier
showers and possibly an isolated lightning strike or two. Snow
levels will start out rather high Thursday, but lower to Mountain
Pass levels Thursday night and early Friday.

A colder air mass is expected to move over the northern Rockies
this upcoming weekend with continued surges of moisture. This
translates into snow or graupel showers down to most valley
floors. However, only intermittent lighter precipitation is


.AVIATION...Scattered showers will increase into the evening,
especially over the southern Bitterroots, southern Clearwaters and
far northwest Montana from Libby/Troy eastward across the Flathead
Valley and Glacier National Park. The heavier showers and the
most widespread mountain obscurations are expected in the southern
Clearwaters eastward across Lost Trail Pass and in the Glacier
National Park area. Local lower visibilities down below one mile
at times can also be expected in these areas. Elsewhere,
scattered light showers will occasionally produce local mountain
obscurations. The showers will decrease late tonight, but patchy
valley fog develops by morning, especially in the vicinity of



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