Area Forecast Discussion
Issued by NWS Great Falls, MT

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674
FXUS65 KTFX 062145
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
245 PM MST Tue Dec 6 2016

.DISCUSSION...
Tonight through Thursday...A few light snow showers are moving
across Central/Southwest MT, but the activity is fairly
light/scattered. Most of the snow showers will end this evening,
with any snow accumulations generally less than a quarter of an
inch. Expect mostly dry conditions Wednesday/Wednesday night as we
are in between systems. The next upper level disturbance will
approach the Rocky Mountain front/Southwest MT by late Thursday
afternoon...with the bulk of the snowfall auguring Thursday
night/Friday. It will be very cold the next few nights, especially
in areas that have some clearing/snow cover. For now I leaned
closer to the colder GFS numbers. Wind chill advisory in effect
for the entire region tonight/Wednesday morning. The wind chill
advisory will likely be extended into Thursday for portions of
the region tomorrow. Brusda

Thursday night through Monday...A high pressure ridge over Central
and Southwest Montana will be flattened Thursday night as a low
pressure trof moves over the West Coast. Moisture ahead of this trof
will cross the Rockies and bring cloudy skies with increased chances
of precipitation. Snow accumulations will mainly be over the western
mountains. Weak high pressure will build again Friday but another
disturbance moving through the flow aloft from the west will
increase the chances of snow again Friday night and Saturday. As
this trof crosses the zones, the associated cold front will bring
another push of cold air into the region. This will keep
temperatures, especially across the northern tier, well below
normals Saturday and Sunday. Weak high pressure will build again
Saturday night and most snow will be limited to higher elevations.
However, another shortwave will be upstream and periods of light
snow will continue Sunday night through the end of the period. Cold
temperatures will continue through the extended forecast period,
especially across the northern half of the forecast area where
temperatures will generally remain 15 to 20 degrees below normals.
Southwest Montana will not be affected as much by the Canadian
air and temperatures will push upwards towards normals.
Zelzer

&&

.AVIATION...
Updated 1750Z.

A cold upper level trough remains in place across the region for
N/NW flow aloft. Cold high pressure continues to nose south into the
region from western Canada as well with a moist low level northerly
flow remaining in place. A weak weather disturbance passing through
ID this afternoon will spread higher clouds and chance for light
snow across SW MT with low clouds persisting across the remainder of
the forecast area through this afternoon. MVFR conditions will
prevail with occasional IFR in areas of low clouds. Some improvement
to ceilings is expected tonight with lower clouds becoming scattered
at times. Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF -12   0 -10   3 /  20  10  10   0
CTB -12  -1 -13  -3 /  10  10  10  10
HLN -10   5  -5  17 /  20  10   0  10
BZN -12   4  -8  17 /  20  10   0  10
WEY -15   8 -14  15 /  20  10  10  20
DLN  -7   7  -4  18 /  20  10   0  40
HVR  -9   2 -10   0 /  10  10  10  10
LWT -11  -1 -11   6 /  20  10  10   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory from 8 PM this evening to noon MST Wednesday
Blaine...Broadwater...Cascade...Central and Southern Lewis and
Clark...Chouteau...Eastern Teton...Fergus...Hill...Jefferson...
Judith Basin...Meagher...Southern Rocky Mountain Front.

Wind Chill Advisory until noon MST Wednesday Eastern Glacier...
Eastern Pondera...Liberty...Northern Rocky Mountain Front...
Toole.

Wind Chill Advisory from midnight tonight to noon MST Wednesday
Beaverhead...Gallatin...Madison.

&&

$$

weather.gov/greatfalls



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