Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 231759

Area Forecast Discussion
National Weather Service Great Falls MT
1100 AM MST Thu Feb 23 2017

Aviation Section Updated


Weather systems to our south will provide for scattered snow
showers through today. Large developing mid level low in WY
bringing moist easterly flow to the region...while an inverted sfc
trough also helping provide lift and moisture to the CWA. The
result will be scattered snow showers today. Currently upslope
snow showers being found along the Rocky Mountain Front area.
These could continue through the morning...with little impacts
expected. Snow then becomes scattered across the region this
afternoon and evening...with the best chances across the south and
portions of the central. Still feel impacts will remain low to
moderate...and confidence is not high enough to issue any
Advisories. Feel SPS for any problem areas will be the best way to
go...unless higher confidence can be determined.
Regardless...those traveling today should be prepared so scattered
slick spots...and reduced visibility in falling snow. Anglin



Moisture in the form of occasional snow showers, light mist/fog, and
at times low ceilings (temporary IFR conditions) will continue
across most terminal locations across the region. The occasional
snow showers will be most prevalent in the upslope areas facing
north and east. Mountain obscuration with widespread MVFR conditions
and temporary IFR conditions will continue into the afternoon and
evening hours. Winds are expected to become light and variable
during the early morning hours as high pressure builds southeast
from the Canadian Province of Alberta. These light and variable
winds will limit mixing during the overnight hours, which may allow
for the formation of fog, especially where widespread snowmelt is
observed. Confidence in the formation of fog at some terminal sites
is low however due to model agreement, thus only trended ceilings
and visibilities down slightly. - Moldan


/ISSUED 430 AM MST Thu Feb 23 2017/

This morning through Saturday afternoon...

The southwest and north-central MT region will continue to reside
in a fairly weak flow pattern with a broad upper trough to our
west over Washington and Oregon. A well-defined upper low over far
south-central Idaho this morning will move east-southeast away
from the area as well over the next 24 hours. Another very well-
defined weather system will move southeast across the region by
late Saturday afternoon and finally change the pattern.

The resulting weather impacts of this pattern through early
Saturday are continuing areas of light snow showers, with more
steady snow at times over higher elevations. However,
accumulations in any one location will be fairly light, and trying
to nail down timing as to when steadier snow may occur at any one
location is almost totally futile more than about 3 to 6 hours in
advance. Contemplated advisory issuance for our southern
counties with this morning`s forecast package, but confidence is
just not high enough to pin down snow amounts and timing beyond
just a very general rough idea. Will continue to monitor for
possible issuance through the next 24 to 30 hours or so.

By Saturday a weather system and associated cold front will move
rapidly south and east across the area. Winds will increase
especially the Rocky Mountain Front Saturday prior to frontal
passage, as well as over the higher elevations of the region.
However, no wind hazards are anticipated at this time. Cassell

Saturday Night through Thursday...A series of weather systems will
move through Western Canada and the PacNW Sunday into early next
week. Most of the synoptic forcing with these systems skirts around
our forecast area to the west and south. Temperatures remain below
seasonal averages as we remain on the cold side of the mid-latitude
jet. Although moisture is limited through this period, a combination
of weak instability combined with orographic and minor shortwave
forcing will continue to produce widespread light snow showers
across much of the forecast area. Continued light snow accumulation
should be expected in mountain areas. Temperatures begin to moderate
by mid-week as the Pacific ridge axis flattens somewhat and moves
inland. The second half of the week is likely to be windy, with
temperatures near average and periods of snow continuing mainly
along and west of the Continental Divide. PN


GTF  30  15  29  11 /  80  20  20  30
CTB  26   9  26   7 /  40  10  10  30
HLN  31  15  28  12 /  30  20  20  30
BZN  29  14  27  10 /  30  30  30  30
WEY  25   7  21   2 /  30  40  50  50
DLN  27  12  23   7 /  30  30  30  30
HVR  30  16  31  13 /  50  20  20  20
LWT  28  16  30  13 /  80  20  30  30



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