Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 261055
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
355 AM MST Sun Feb 26 2017

.DISCUSSION...

Today through Tuesday...Surface observations reveal pressure rises
as a cold front crosses the international border and moves into
North-central Montana. Convergence is helping to produce scattered
light snow showers along and behind the cold front. Water vapor
satellite shows an energetic shortwave trough west of the
Washington coast. Moisture extending downstream to the east of
this system is associated with low clouds now covering the western
half of Montana. A shallow northeasterly upslope flow develops
today along the east slopes of the Lewis range and the north
slopes of the Big/Little Belt mountains with the deepening cold
air mass. This will maintain light snow for these upslope areas of
N-central MT today, with periods of heavier snow possible for a
short time along the advancing cold front. The upstream shortwave
system turns inland and tracks across Idaho and Wyoming tonight.
As it does so, low- to mid- level southerly winds create lift
over the colder air mass. Thus a band of light- to moderate
snowfall is anticipated tonight across central MT. Overall, this
system is expected to produce 2-4 inches of snow at lower
elevations, with 3 to 6 inches for mountain passes. Winter weather
advisories are in effect as travel will become hazardous tonight
through the peak travel period Monday morning. Accumulating snow
will spread further into southwest MT Monday afternoon, possibly
affecting travel over Monida/Raynolds passes and the West
Yellowstone area. Scattered snow showers continue Monday night
into Tuesday amid an unsettled northwest flow that may continue to
favor the Bridger range. Another weak disturbance passes Tuesday
to maintain scattered snow showers, but with increasing southwest
winds along the Rocky Mountain Front.  PN

Tuesday night through Sunday...Period begins with a fast NW flow
aloft over the region. Surface low develops east of the Rockies in
AB Tues night and quickly moves SE across eastern MT on Wed.
Increasing winds Tuesday night through early Wednesday with strong
winds possible along the east slopes of the Rockies. Enough snow-
cover will probably be present for potential blowing/drifting snow
issues across western portions of north-central MT, particularly
where winds will be strongest along the Northern Rocky Mtn Front.
Fast W/NW flow aloft continues through the rest of the upcoming week
with next stronger shortwave moving east along the MT/AB border
Friday night. Models continue to advertise favorable pattern for
widespread strong winds in association with this feature
Friday/Friday night but have backed off some with the strength of the
low emerging east of the Rockies on the Canadian Prairies as well as
overall wind speeds aloft. Temperatures will gradually warm through
the later part of the upcoming week before cooling again next
weekend. Hoenisch

&&

.AVIATION...
UPDATED 0540Z.

A moist westerly flow aloft will continue mountain-obscuring snow
across the area through the period. Otherwise, clouds and snow will
increase over the area from the northwest between 06Z and 12Z,
especially over North Central Montana, as a shortwave trough
approaches the Pacific Northwest. A Canadian cold front will move
south over North Central and Central Montana through 18Z, shifting
winds more northerly there and gradually lowering flight conditions
from mostly VFR to mostly MVFR/IFR by 10Z at KCTB, by 15Z at KHVR
KGTF KLWT, and by 18Z at KHLN, which should continue through at
least Sunday evening. The cold front, and consequently the lower
flight conditions (mainly MVFR) and snow, will be slower to reach
far Southwest Montana (including KBZN and KEKS), likely not until
after 18Z.  Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  24   8  22  14 /  70  70  30  10
CTB  19   3  17   5 /  60  50  30  20
HLN  28   8  23  10 /  70  70  30  20
BZN  29  10  25   9 /  30  40  40  30
WEY  18   7  21   5 /  60  70  70  40
DLN  26  13  26  10 /  30  30  40  20
HVR  25   9  22  13 /  50  50  30  20
LWT  25  10  21  10 /  50  70  50  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 AM this morning to 11 AM MST
Monday Cascade...Central and Southern Lewis and Clark...Eastern
Glacier...Eastern Pondera...Eastern Teton...Fergus...Judith
Basin...Meagher.

Winter Weather Advisory until 11 AM MST Monday Northern Rocky
Mountain Front...Southern Rocky Mountain Front.

&&

$$

weather.gov/greatfalls


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