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000
FXUS65 KTFX 132152
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
252 PM MST Fri Dec 13 2019

.SYNOPSIS...
A cold front continues to slowly move southward through Southwest
MT tonight, while several upper level disturbances will move
through the region. Expect scattered areas of snow over the region
tonight, with the snow being more confined to mountain areas by
Saturday. Temperatures will generally average about 4 to 8 degrees
below normal this weekend. A westerly flow aloft sets up over the
region next week, resulting in a slow warming trend along with
mostly dry conditions.

&&

.DISCUSSION...
Tonight through Saturday...An area of snow continues to affect
locations east of a line from Shelby to Kings Hill Pass. The
snowfall was heaviest around Big Sandy and south of Havre at 230
PM, with snowfall rates generally less than one inch per hour now
falling. The show should begin to diminish this evening. Winter
highlights will remain in place. If the snow does not diminish by
5 PM around Havre/Chinook, the winter weather advisory could be
extended in this region for a few hours. Additionally, another
wave of moisture is progged to move into far Southwest MT later
this evening. Accumulating snow will be confined mainly to areas
south of a line from Dillon to Big Sky. New snow accumulation
tonight and into Saturday will generally range from 1 to 3 inches
in this area. Thus no advisory will be issued at this time, but
should snowfall look more likely, an advisory could be issued
later tonight or on Saturday. Cold air continues to push south,
but slowly. The boundary stalled out around Dearborn, but should
start to advance slowly southward this evening. Overall, below
normal temperatures are expected on Saturday, with snow showers
becoming more confined to the western mountains by Saturday
evening.

Sunday through Monday...An unsettled northwesterly flow aloft will
reside over the region for Sunday into Monday. There will be a
small chance for a passing snow shower, mainly right along the
Rocky Mountain front. Any snow accumulations will be very light.
Expect below normal temperatures to continue, with Sunday likely
being the coldest day.

Tuesday through Friday...Weak upper level ridging over the region
on Tuesday will transition to a more brisk westerly flow aloft
over the area. There is a chance for some blowing snow, mostly
over North Central MT for Tuesday into Wednesday, as westerly
winds increase aloft. Otherwise, mostly dry conditions are
expected across the area for much of the second half of next
week. Afternoon temperatures will trend towards a slow warming
trend, with afternoon highs about 4 to 8 degrees above normal by
next Friday. Brusda

&&

.AVIATION...
Updated 1125 AM MST Thu Dec 12 2019 (13/18Z TAF period)

Widespread IFR to LIFR ceilings are noted over the north-central
Plains, impacting KGTF, KLWT, and points north. A band of moderate
to locally heavy snow is oriented mainly from Sweetgrass NE of
KCTB southeast to KLWT at 18z, and is gradually moving east and
northeast. This band is bringing IFR to LIFR visibility reductions
at times, and may shift toward KHVR in the coming hours this
afternoon. Terrain obscuration will be an ongoing concern for
north-central and Southwest MT thru the period. Southwest MT
airports should have fair conditions thru this evening, with MVFR
to locally IFR conditions developing tonight into Saturday with
lowering clouds and scattered snow showers. -Kredensor

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  15  27  16  26 /   0  10  10  10
CTB   7  23   9  21 /  10   0   0   0
HLN  18  30  16  29 /  10  20  10  10
BZN  14  29  11  26 /   0  20  20  10
WEY  10  22   3  18 /  40  30   0  10
DLN  12  26   7  24 /  40  40  10   0
HVR   6  16   8  20 /  20  20  10  20
LWT  12  24  14  24 /  40  20  10  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM MST this afternoon Northern
Rocky Mountain Front...Southern Rocky Mountain Front.

Winter Weather Advisory until 11 PM MST this evening Cascade...
Chouteau...Fergus...Judith Basin...Meagher.

Winter Weather Advisory until 5 PM MST this afternoon Blaine...
Hill...Liberty.

&&

$$

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