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FXUS65 KTFX 230001
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
600 PM MDT Sat Sep 22 2018

...UPDATED AVIATION SECTION...

.SYNOPSIS...

Generally dry conditions with increasing cloud cover can be
expected through the rest of today. A cold front will move across
the region late tonight through Sunday. This front will bring with
it chances for showers and cooler temperatures through Sunday.
Cool temperatures and scattered showers will then linger to start
the work week on Monday.

&&

.DISCUSSION...

Tonight through Monday...A flattening ridge will allow for
southwest flow through tonight bringing increased moisture to the
area and increased cloud cover. This flow has made for some near
to slightly above average temperatures for today...with some
breezy winds at times. A cold front, currently across the Pacific
NW, will push across the region late tonight through the day on
Sunday. Overall chances for precipitation remain across much of
the same areas as previous forecasts, although the better chances
may have shifted slightly south southeast, with the best chances
now from Helena to Great Falls to near Havre and southeast of this
line including much of southwest MT. Snow levels should remain
above 7000 feet during the day, leaving mainly rain and perhaps an
isolated thunderstorm as the expected results. This front will
continue to progress out of the area Sunday night, diminishing
shower activity from northwest to southeast. Snow levels may lower
to around 6500 feet by Monday, causing some mountain snow
possible across the Rocky Mountain Front and the mountains in the
southwest. Monday then sees the typical northwest flow pattern
behind the front. Below average temperatures and scattered showers
are expected. High temperatures are expected to be in the 60s on
Sunday and 50s on Monday. Low temperatures will remain in the 30s
and 40s throughout the short term period.

Monday night through Saturday...Drier conditions and weak ridging
move across the area Tuesday and Wednesday. Temperatures will be
slightly below seasonal averages during this time period. Models
continue to suggest strong amplification of the upper ridge from
the eastern Pacific northward late next week, supporting a cross-
polar flow and transport of a significantly colder airmass south
by next weekend. Confidence in the overall trend to much colder
temperatures is growing along with potential for wintry
precipitation, even at lower elevations, however at this time
range additional fluctuations in model solutions are likely over
the next several days before any specific details can be
highlighted. Hoenisch

&&

.AVIATION...
Updated 0000Z.

VFR conditions with mid and high cloudiness are expected for the
terminals through around 09Z, but the Rocky Mountain Front will
likely be obscured by precipitation from the moist southwest flow
aloft. Between 09Z and 12Z, a low pressure trough approaching from
the Pacific Northwest will develop a band of precipitation with
mountain obscuration and occasional MVFR conditions over a KHLN-KGTF-
KHVR line. This precipitation band will then move south over the
remainder of the forecast area throughout the day on Sunday, with
precipitation decreasing after 18Z along the aforementioned line.
The area along the northern east slopes of the Rockies (including
KCTB) will avoid this band of precipitation, but low clouds and fog
with MVFR/IFR conditions may move into that area from Canada between
09Z and 16Z. Otherwise for that area, showers may move in after 16Z
due to weakly unstable air. Coulston

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF 46 62 39 57 / 40 60 10 40
CTB 40 61 39 57 / 10 20 10 30
HLN 48 63 39 59 / 20 40 10 30
BZN 43 65 37 59 / 0 30 30 20
WEY 35 63 26 57 / 0 20 40 10
DLN 44 64 32 59 / 10 30 20 10
HVR 46 63 40 58 / 30 50 20 30
LWT 43 59 36 54 / 10 60 20 40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

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