Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 280238
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
838 PM MDT Wed Mar 27 2024

.SYNOPSIS...

After a warm and dry day today, mountain snow and valley rain
arrive for portions of Southwestern and North Central Montana on
Thursday. After a cooler and slightly unsettled weekend, warm and
dry weather return for the first half of the work week.

&&

.UPDATE...

No need for any significant updates for the overnight period into
Thursday. Temperatures and winds are trending similar to the
current forecast. High- and mid-level cloudiness continues to
increase from the west, but any light showers so far have remained
along and west of the Continental Divide. -Coulston

&&

.AVIATION...
550 PM MDT Wed Mar 27 2024 (28/00Z TAF Period)

Expect increasing clouds overnight, along with snow developing
along the divide and over Southwest MT by 12z Thu. Expect
rain/snow to continue to move northeastward through the CWA
during the day on Thursday. IFR conditions are possible in/near
any heavier snow showers. Most of the heavier snow showers should
only last about an hour as they move through. Showers start to
decrease in coverage area Thursday evening. Mountains/passes will
become obscured at times after 09z Thu through 06z Fri. Brusda

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PREV DISCUSSION...
/ISSUED 550 PM MDT Wed Mar 27 2024/

Key Points:

-Snow in the mountains of Madison and Gallatin County may result
in icy roads after sunset on Thursday

-Temperatures cool for the weekend with areas of light snow

-Warmth returns next week

Short term (through Friday)... Early morning breezes across the
plains this morning are beginning to diminish as pressures fall
across the Northern Rockies, relieving the pressure contrast with
a lee trough that was over the plains earlier today. Aside from
the breezes, today will be a warm day across most of the area,
with the majority of the area seeing highs reach the upper 40s
and low 50s under a mix of sun and clouds.

Winds will begin to increase across the higher terrain of
Southwestern Montana this evening and overnight as a jet streak
associated with our next system arrives overhead. While the
impacts of this should be minimal, there is the possibility of a
few isolated areas of blowing snow. As we head further into the
overnight, we will see a few areas of snow develop along the
MT/ID border, particularly in the West Yellowstone area, but
these should also be of minimal impact during the overnight
hours. Snow will begin to become more intense and widespread
during the day on Friday as moisture continues to work into
Montana, with mountain snow and valley rain extending as far
north as the Golden Triangle region, though here precipitation
should be of little to no concern and will be welcomed, even if
amounts struggle to exceed a tenth of an inch or so. The biggest
area of concern will be in the mountains of Madison and Gallatin
Counties where the heaviest snowfall will occur; however, the
majority of this will fall during the daytime with temperatures
in the upper 20s and low 30s. These temperatures, combined with a
strong late March sun angle, will limit impacts to roads during
the daytime, and may even be a limiting factor for accumulations
on non paved surfaces. We will have to watch for a freeze up
after sunset, but with the expectation of limited impacts we will
hold off on issuing a Winter Weather Advisory for the moment, and
will instead focus our efforts on messaging about the potential
for a freeze up after sunset. Rain and snow will push off to our
east Thursday night, leaving just a few leftover instability snow
showers Friday afternoon, mainly over the Southwest. Otherwise
Friday will be a relatively calm weather day with highs in the
30s and 40s.

Extended (Saturday through next Wednesday)... As broad upper
level troughing continues across the Northwestern US, expect
cooler and slightly unsettled weather to continue through the
weekend as highs struggle to reach 40 across the plains, while
the southwest valleys will warm a bit further with highs in the
mid 40s Saturday and Sunday. As we head into the work week, we
will see a quick shift towards upper level ridging as an upper
level low across the Southwest US begins to move eastward. As it
does so, temperatures will quickly rise into the 50s and even 60s
across the area for the first half of the work week. Unsettled
weather may return around the middle of next week as a
disturbance potentially moves through the area. Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  33  49  25  41 /  10  60  20  20
CTB  26  47  21  38 /  10  20   0  10
HLN  34  50  27  48 /  20  60  10  20
BZN  31  50  23  47 /  10  70  50  20
WYS  26  39  17  39 /  80 100  50  30
DLN  32  48  25  45 /  20  80  20  10
HVR  25  47  22  38 /  10  40  10   0
LWT  30  50  23  41 /  10  80  30  20

&&

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

$$

http://www.weather.gov/greatfalls


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