Area Forecast Discussion
Issued by NWS Missoula, MT

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000
FXUS65 KMSO 202011
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
211 PM MDT Sun Jun 20 2021

.DISCUSSION...A Canadian cool front has pushed across the
Continental Divide into western Montana this afternoon. Light
(10-15 mph) north-northeast winds have developed across western
Montana behind the frontal passage. The bulk of shower activity
has shifted south and east along the Continental Divide in
southwest Montana. The heaviest precipitation earlier this morning
was observed in eastern portions of Glacier National Park and the
Flathead National Forest, where around half an inch of
precipitation fell. Skies will quickly clear out later this
evening and overnight, as high pressure begins to build into the
Northern Rockies.

Warm and dry weather returns across the Northern Rockies Monday,
as high pressure amplifies across the region. High temperatures
will soar into the 80s across western Montana valleys and into the
90s and low 100s across lower elevations of north central Idaho.
A plume of mid to upper level Pacific moisture embedded within
southwesterly flow will move across central Idaho and southwest
Montana Tuesday afternoon. Marginal instability and lift will
allow for high based isolated thunderstorms to developing during
the late afternoon and evening hours.

Model ensemble guidance continues to depict a high amplitude
blocking pattern across the western U.S. Thursday through next
weekend. The blocking high has trended further north and east the
last few runs. Recent model ensemble guidance suggests the center
of the high may set up across northwest Montana, eastern
Washington, or southern Canada. If this solution verifies, near
record to record high temperatures will occur, particularly across
north central Idaho. /Lukinbeal

&&

.AVIATION...A Canadian cold front has pushed across the
Continental Divide into western Montana this afternoon, with light
(5-10 kt) north- northeast winds expected to continue through the
evening hours. A modest N-S oriented pressure gradient across
Lemhi County Idaho will maintain frequent 20-25 knot wind gusts
through at least 21/0400Z, with impacts expected at KSMN. The bulk
of shower activity associated with the frontal passage has
shifted south and east along the Continental Divide in southwest
Montana. Skies will quickly clear out later this evening and
overnight as high pressure begins to build into the Northern
Rockies. /Lukinbeal

&&

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

&&

$$


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