Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 022051
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
251 PM MDT Thu Apr 2 2020

.DISCUSSION...

An anomalously cold airmass will continue to produce snow showers
over the Northern Rockies through tonight. Much of the snow
impact to low elevations has mostly ended, however a quick shot of
snow is possible over mountain pass roadways, causing conditions
to deteriorate for a short amount of time. Snow shower activity
should diminish after sunset.

Very early Friday morning, another cold low pressure circulation is
anticipated to move across the Northern Rockies and increase snow
showers through the remainder of the day. The early morning hours
will be susceptible to ice and snow build-up on area roadways
across northwest Montana, particularly in the Kootenai River
Country and Glacier Park region (including US Highway 2). Snow
accumulations up to several inches are possible, particularly near
Marias Pass. By Friday afternoon, daytime heating and a high sun
angle should quickly dry off area roadways and diminish the impact
to roadways.

Snow showers will continue to be present across the Northern Rockies
throughout the remainder of Friday and into Saturday. For the most
part, quick bursts of light snow on mountain pass roadways will be
the greatest weather impact. Expect temperatures to remain quite
cold for early April.

The next upper wave, seen on the water vapor about 1800 miles due
west of Missoula over the northeast Pacific, is expected to make
its trek southeast towards Oregon by Saturday and then over
northwest Montana by Sunday morning. Models have been trending
this feature further north each run, but are in more agreement
today. This would bring light snow to central Idaho and northwest
Montana Saturday night into Sunday morning.

Behind this wave, a shortwave ridge follows it, but with clouds
streaming north ahead of a more potent trough just offshore of
California. Expect a decrease in precipitation chances later
Sunday with highs just shy of seasonal averages.

On Monday, moisture moving north will most likely be in the form
of light snow to the higher elevations of southern Idaho County,
Lemhi County and maybe portions of southwest Montana. Otherwise
expect a lower chance for precipitation elsewhere with seasonable
temperatures. Averages for April 6 include 49 degrees at Butte,
53 at Kalispell, 54 at Grangeville ID, 55 at Salmon ID and 56 for
Missoula.

There are indications that a warming and drying trend will
continue Tuesday and Wednesday...possibly Thursday.

By next weekend, the pattern becomes more active with a chance for
another Canadian cold front to bring winter impacts near the
Continental Divide.

&&

.AVIATION...Intense, short-duration snow showers will be present
across the Northern Rockies through 03/0300Z. KGPI and KMSO are
the most likely terminals to experience sudden decreases in
ceiling and visibility during this time. Snow showers will
continue to diminish over high terrain after 03/0300Z. Another
cold storm system is anticipated to move across northwest Montana
beginning 03/0900Z, bringing visibility and ceiling down across
the air space through 03/1800Z. KGPI and KMSO are again the most
likely terminals to be impacted by these diminished flying
conditions. High terrain will mostly be obscured during the next
24 hours.

&&

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

$$


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