Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 232101

Area Forecast Discussion
National Weather Service Great Falls MT
301 PM MDT Fri Mar 23 2018


A weak upper level disturbance will cause scattered light rain or
snow showers across North-central Montana this evening. Otherwise,
fair weather prevails overnight. Another round of rain and mountain
snow showers spreads through the area Saturday afternoon, with
drier conditions on Sunday. Temperatures this weekend will range
from the teens, 20s and lower 30s overnight, with daytime highs in
the mid 30s to mid 40s.



Tonight through Saturday night...Satellite imagery reveals mostly
clear skies and dry air aloft across the forecast area this
afternoon, with two exceptions. First, low stratus has been slow
to erode across portions of Hill and Blaine counties north of
Highway 2. Second, scattered fair weather cumulus clouds across
southwest Montana reveal weak low level instability. A minor
shortwave disturbance aloft, presently located over southwest
Oregon, will arrive quickly in the southwest flow aloft. Expect
scattered wet snow showers to spread from southwest to northeast
this evening through the early morning hours. Snow accumulations
up to about 1 inch are possible tonight over the central mountain
ranges. Gusty west winds over western portions of North- central
MT this afternoon will decrease tonight as higher pressure builds
from the west. However, the passing wave aloft could shift winds
back to the east along the HiLine. This presents a low confidence
possibility that fog could return to the Milk River valley east of
Havre once again. Just as showers end early Saturday morning,
another stronger system will once again spread rain and mountain
snow showers across the region from southwest to northeast on
Saturday. Cooler temperatures aloft provide weak instability
aloft, such that a few of these showers could become briefly
stronger than others. Precipitation from this system will be
focused more over southwestern Montana, where mountain snow totals
of 1-3 inches will be possible through Saturday. Skies gradually
clear Saturday night as the system pulls away to the northeast.
Temperatures remain near seasonal averages, with mid 40s during
the day and freezing overnight. Snowmelt and icejam flooding
concerns are addressed in the hydrology section. PN

Sunday through Friday...An eastward-moving longwave trough aloft and
embedded shortwave disturbances cross our region Sunday and Monday.
The best potential for precipitation looks to be over the
southwest mountains, where snow showers are expected. Ridging
aloft builds-in from the Pacific Northwest Tuesday. A shortwave
disturbance embedded within the northwest flow is projected to
affect the CWA on Wednesday and Wednesday night. This scenario
should result in breezy conditions along the Rocky Mountain Front,
and periods of mountain snow showers with a mix of rain/snow
showers at lower elevations. Skies clear on Thursday, with another
in a series of clipper systems passing Friday and Saturday. Overall,
temperatures will trend below normal through the period. PN/Jaszka


Updated 1122Z.

VFR conditions prevail under mainly clear skies. Satellite imagery
shows boundary layer cumulus starting to develop across southwest
MT. Expect these clouds to become more widespread through the
afternoon, possibly producing -SHRASN moving southwest to northeast
late this afternoon through late evening. Temporary MVFR/IFR
conditions may be possible under any of these showers. PN



The local emergency manager for Chouteau County continues to report
minor flooding impacts over portions of Chouteau County. Several
roadways have reported water on the road or are impassable. Some
roadways are, but not limited to, Promise Land Road, Antelope Lake
Road, Brady Road and Clear Lake Road. Additionally, ice jams on
the Marias River and Teton River have developed. Portions of the
Teton River near Loma are out of its bank because of the ice jam.


GTF  30  46  23  42 /  40  20  10  10
CTB  25  35  18  36 /  10  10  20  10
HLN  33  44  23  41 /  20  20  20  10
BZN  34  43  21  40 /  10  40  20  20
WEY  26  33  13  33 /  60  70  30  40
DLN  31  38  19  35 /  10  10  10  30
HVR  25  37  19  35 /  20  20  30  10
LWT  30  42  21  39 /  40  20  30  20


Areal Flood Advisory for snowmelt remains in effect until 4pm MDT
Saturday for Chouteau County.


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