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fxus65 ktfx 191225 
afdtfx

Area forecast discussion
National Weather Service Great Falls Montana
526 am MST Tue Nov 19 2019

..aviation section update...

Synopsis...

Areas of rain and snow will spread from northwest to southeast
today. Most of the accumulating snow today will occur over the
northern rockies and along the hiline. Rain changes to snow at lower
elevations this evening and spreads across much of north-central
Montana overnight. Snow ends from west to east on Wednesday morning.

&&

Discussion...

The system that will dominate our weather pattern for the next
approximately 36 hours has been a bit challenging to forecast.
Having said that, yesterday, numerical models finally started to
come into better alignment in their solutions, and forecast
confidence has improved. Precipitation is expected to become
widespread from west to east, particularly along our northern border
with Canada.
Rainfall can be expected initially; however, as temperatures
fall, rain will become snow. The northern Rocky Mountain front
will experience accumulations ranging from 6 to 10 inches, with
Marias Pass, Rogers Pass and MacDonald Pass forecast to receive
about 3 to 6 inches of snow. Lower elevations of Teton and Lewis
And Clark counties, as well as areas along the hi-line can expect
to receive 1 to 4 inches of snow accumulation from this event. As
the track of this passing trough becomes still more clear,
highlights will be adjusted as may be needed. The rapidity with
which temperatures fall will effect snowfall totals, and we will
continue to monitor and update as necessary. Expect wet roadways
to become icy. Please, use caution on slippery surfaces.
Additionally, with falling temperatures and wet conditions, those
performing outdoor activities may be in danger of hypothermia.
- Fogleman

Wednesday night through next Tuesday...

Partial clearing is expected to take place Wednesday night as low
temperatures dip into the single digits and teens. Then mostly
dry conditions along with moderating temperatures are expected
through early Sunday as high pressure builds into the area.
However, it appears that a weak mid-level trough will briefly
interrupt the ridge of high pressure on Friday, bringing an
increase in cloud cover and some breezy westerly winds,
especially over the Rocky Mountain front and the north-Central
Plains. Currently, model guidance is keeping this system dry but
a few rain and mountain snow showers can't be completely ruled out
given the relatively moist northwesterly flow aloft. High
pressure then attempts to regain control on Saturday but another
weak wave may traverse the region. The result will be continued
mild temperatures and strengthening westerly winds over the Rocky
Mountain front north-Central Plains. These winds may need to be
monitored for high wind products should this trend continue. Then
on Sunday, broad troughing is expected approach the region and
break down the ridge of high pressure. This is expected to usher
in more potentially strong westerly winds for north-central
Montana, before colder and unsettled weather moves through the
region later Sunday into Monday and Tuesday.

&&

Aviation...
updated 526 am MST Tue Nov 19 2019 (19/12z taf period)

Begin this taf period with VFR conditions at all airfields. By
19/15z, lower ceiling and reduced visible in -ra becoming -sn cause
conditions to begin to degrade into the MVFR range. As conditons
degrade further, klwt is forecast to become IFR, with khvr falling
into the LIFR range. Expect mountain obscurations and aircraft
icing.
- Fogleman

&&

Preliminary point temps/pops...
gtf 43 25 33 19 / 70 70 60 0
ctb 35 23 33 18 / 80 80 20 0
hln 45 24 34 15 / 70 60 40 0
bzn 45 24 35 12 / 50 50 40 0
wey 41 19 33 5 / 60 40 30 10
dln 46 23 34 14 / 50 30 30 0
hvr 37 21 33 18 / 80 90 20 0
lwt 43 23 29 16 / 70 80 60 10

&&

Tfx watches/warnings/advisories...
Winter Weather Advisory from 8 am this morning to midnight MST
tonight central and southern Lewis And Clark...southern Rocky
Mountain front.

Winter Weather Advisory from 11 am this morning to midnight MST
tonight Blaine...Hill.

Winter Weather Advisory from 8 am this morning to midnight MST
tonight eastern Glacier...Liberty...Toole.

Winter Storm Warning from 8 am this morning to midnight MST
tonight northern Rocky Mountain front.

&&

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