Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 300917

Area Forecast Discussion
National Weather Service Missoula MT
317 AM MDT Sat Sep 30 2023

.DISCUSSION...A closed low pressure system will continue to dig
southward into Nevada today. This will place western Montana and
north-central Idaho under southerly flow aloft, ushering moisture
and mild mid level temperatures into the region. Most locations
will see light to moderate precipitation today, particularly
through west-central Montana and north-central Idaho. The
afternoon and early evening in particular looks to be the wettest
timeframe, with areas from Glacier National Park, southwest
through Missoula and into north central Idaho having a 50 to 70
percent chance of seeing at least 0.10" of precipitation. Snow
levels will be increasing through the day today, starting between
6500 to 7000 feet this morning. A light dusting of snow is
expected in the higher terrain, especially near Glacier National
Park where snow levels are the lowest.

The main low pressure circulation will eject northeastward into
southern Idaho during the day on Sunday. This will shift another
round of precipitation into southwest Montana, Lemhi County and
north central Idaho. Snow levels will be up close to 8000 feet
where the heavier precipitation occurs, so only the highest peaks
of southwest Montana will see snowfall. Northwest Montana is
expected to largely miss out on this secondary period of
precipitation. In fact, there may be a few breaks in the cloud

The low pressure system will slowly meander out of the region and
broaden into more of an open wave for Monday into Tuesday.
Continued showers will be possible, but widespread persistent
precipitation will be ending. Temperatures will begin to warm
slightly, though still remaining below seasonal normals.

Forecast models continue to trend with high confidence towards a
ridge of high pressure building back over the region by mid week.
At this point, only 10 percent of the model solutions reflect a
trough remaining over the region. Given the recent trends,
temperatures are expected to warm, perhaps above seasonal normals
by the end of the work week. This would also bring a period of
drier conditions, possibly lasting into next weekend.


A trough of low pressure will continue to dig to the south of the
Northern Rockies airspace today. This trough will lead to the
formation of a closed mid-level low pressure system by Sunday. In
association with this system, waves of clouds and moisture will
continue to stream in. This will lead to persistent cloud cover
today, and periodic rain showers. Lower ceilings, reduced
visibility, and mountain obscurations are all expected during
periods of rain. /KS



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