Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 221818
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1120 AM MST Wed Feb 22 2017

Aviaton Section Updated

.UPDATE...

A weak upper level disturbance is currently bringing snow across
portions of central and northern Montana. Coverage is slightly
less than expected yesterday...with some moderate snow being
observed at times across central portions. With impactful snow
pretty much ended along the Rocky Mountain Front...went ahead and
expired their advisories. The remainder of the advisories will
continue...however...best chances for impactful snow will be
mainly east of Great Falls to a line from Havre to Lewistown. Will
monitor for further updates to the advisories for the next
forecast package. Overall looks like snow may diminish this
evening...except across far eastern portions. Another weak wave
looks to push in from Canada tomorrow...perhaps bringing scattered
light and low impact snow. Anglin

&&

.AVIATION...
Updated 1820z.
Light snow continues to affect areas mainly east of Great Falls.
That trend will continue into Thursday morning. Low ceilings and
visibilities below 1 mile can be expected at times. Otherwise a few
scattered light snow showers will be possible for areas west of
Great Falls. Kept fog out for now...but will continue to monitor.
Brusda

&&

.PREV DISCUSSION...
/ISSUED 440 AM MST Wed Feb 22 2017/

Today through Friday Afternoon... Snow showers will continue to
impact the forecast area for the next couple of days, with variable
yet light snow accumulations across the region depending on smaller
scale features that are difficult to pin down to exact areas. The
most significant shower coverage should be right along a front over
the Plains that extends from near I-15 to US Highway 89 east of
Great Falls and points north and east. This boundary will likely
push north and east toward our northeastern counties today, then
become stationary and weaken overnight tonight. Thus, the best
accumulating snow as well as widespread low ceilings and fog is
expected just north and east of this boundary over north-central MT.
Another weak system moves across SW MT by early this afternoon and
will help to produce snow showers over most mountainous areas. This
region will have more low level instability, so expect the snow
showers to be a bit more intense but also more hit-and-miss than the
shower activity associated with the surface front over the northeast
Plains and along the Canadian border.

Snow shower activity will begin to become more isolated over the
Plains by Thursday and Friday as a broad upper level trough
remains just to the west, with more scattered to possibly
numerous coverage toward higher elevations and across the southern
counties of SW MT with weak lower level northerly upslope flow.

With continued cloud cover across the region, temperatures will
continue to trend cooler but with a relatively smaller diurnal
range with teens and 20s for highs across much of the region, with
colder temperatures in the single digits above zero and teens at
night over the Southwest valleys. Cassell

Friday Night through Wednesday...A surface cold front moves into N-
central MT Friday night. The front could produce areas of light snow
beneath a weak overrunning southwest flow aloft, with flurries
continuing but gradually tapering through much of the day Saturday.
Generally fair, drier, and cold weather follows for Sunday and
Monday. Isolated, mainly mountain snow showers will continue,
associated with weak disturbances in the northwest flow aloft.
Temperatures will fall to around 10 to 15 degrees below average
through Monday night, with overnight lows in the single digits. A
stronger Pacific trough is forecast to develop Monday night
somewhere over the interior U.S. west. This could increase snow
chances for southwest MT on Tuesday, with possible travel hazards
heading into ID. Model solutions bring the cold snap to an end on
Wednesday with broad ridging over the PacNW. A strong Clipper system
developing in the NW flow downstream of the ridge could produce a
period of strong downslope winds Wednesday or Thursday. Confidence
in these late period model solutions remains low. PN

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  21  29  16 /  60  40  40  20
CTB  33  18  25  11 /  60  40  40  20
HLN  37  18  28  13 /  30  30  30  20
BZN  35  15  28  14 /  40  30  50  40
WEY  27   7  23   5 /  40  30  40  40
DLN  33  12  25  10 /  40  40  40  30
HVR  37  26  32  19 /  60  50  50  30
LWT  34  21  29  15 /  80  60  40  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MST tonight Blaine...
Cascade...Chouteau...Eastern Pondera...Eastern Teton...Fergus...
Hill...Judith Basin...Liberty...Meagher...Toole.

&&

$$

weather.gov/greatfalls



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