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FXUS65 KTFX 221030
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
430 AM MDT Wed May 22 2024

.SYNOPSIS...

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Isolated afternoon and evening thunderstorms develop and move
through the region, again, today. The main impact from these
storms is strong and erratic gusty winds. As the day progresses,
widespread precipitation impacts the region. Significant snow
amounts are forecast for mountain elevations, with wintry impacts
to some lower elevations, as well. This system continues to
impact the region into the early hours of Friday morning.
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.DISCUSSION...

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Note: The forecast area for the National Weather Service Great
Falls Weather Forecast includes north central, central and
southwest Montana.

Today and Tomorrow...An upper level closed area of lower heights
rolls southeastward across The Treasure State. The resultant
impacts include precipitation that enters our region from the
west, and becomes widespread throughout the day, today.
Temperatures cool, and significant amounts of snowfall are
forecast across many of the mountainous regions of central and
southwest Montana. For this reason, most of these mountain regions
are under Winter Storm Warnings, with The Snowy mountains added
under a Winter Storm Warning with the issuance of this forecast.
The probability of snow amounts exceeding 6 inches, is at 80% or
more. With the approach of the Memorial Day Weekend, we are
particularly concerned for those who may wish to venture into the
backcountry. The conditions that we are forecasting are associated
with high incidents of hypothermia. Having said this, our concern
is not limited to those in the backcountry. Some mountain passes
will be dangerous. Additionally, some of our lower elevations are
forecast to experience impacts from snow. Surfaces will be slushy
and slippery. This system exits the region by early Friday
morning; however, considering the amount of moisture forecast,
flooding impacts are a concern. Please, see the HYDROLOGY section
below for more details.

Friday through Sunday...Active weather continues with only short
reprieves.

Monday and Tuesday..The forecast is for warm, dry and mild
conditions, with Tuesday`s low elevation high temperatures
ranging in the mid 70s to low 80s.

Wednesday...The mid week period of next week shows a slight chance
of precipitation; however, confidence is low, as this system is
several days out.
- Fogleman
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.AVIATION...
22/06Z TAF Period

VFR conditions prevail through the overnight under increasing mid
level cloudiness. The next system arrives through the day Wednesday.
The initial concern will be for lower elevation rain showers and
scattered thunderstorms with higher elevation snow showers through
daylight hours. Gusty winds and small hail will be the concern with
thunderstorms that form. Then, precipitation transitions to be more
stratiform in nature (Ceilings lowering) with snow levels falling
down as low as valley floors at times Wednesday night. Expect
mountain obscuration from Wednesday afternoon onward into Wednesday
night. -AM

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

&&

.HYDROLOGY...

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A Flood Watch remains in effect for the Little Belts tonight into
Friday. The chances for an inch and two inches of precipitation
have increased (Largely around 70% and 40% respectively) for the
Little Belts over this period. There is some uncertainty as to how
low snow levels fall with this system. Nonetheless, if most
precipitation across the Little Belts Falls as rain, there are
concerns for flooding on creeks and streams in the area given
recent precipitation/saturated soils.
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&&

.PRELIMINARY POINT TEMPS/POPS...
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GTF  57  37  48  36 /  90  90  80  20
CTB  53  34  51  35 / 100  80  40  30
HLN  61  37  48  36 / 100 100  90  10
BZN  60  32  45  28 /  90 100 100  20
WYS  48  25  41  24 /  80  90  80  20
DLN  57  30  44  26 / 100 100  90  10
HVR  57  37  53  36 /  70  70  40  20
LWT  56  34  43  31 /  80  90  90  20
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.TFX WATCHES/WARNINGS/ADVISORIES...
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Winter Storm Warning from 6 PM this evening to noon MDT Thursday
for Elkhorn and Boulder Mountains-Northwest Beaverhead County-
Ruby Mountains and Southern Beaverhead Mountains-Southern Rocky
Mountain Front-Upper Blackfoot and MacDonald Pass.

Winter Weather Advisory from midnight tonight to 6 PM MDT
Thursday for Gates of the Mountains.

Flood Watch from this evening through Friday morning for Little
Belt and Highwood Mountains.

Winter Storm Warning from 6 PM this evening to 6 PM MDT Thursday
for Big Belt, Bridger and Castle Mountains-Gallatin and Madison
County Mountains and Centennial Mountains-Little Belt and
Highwood Mountains.

Winter Weather Advisory from 6 PM this evening to 6 PM MDT
Thursday for Beaverhead and Western Madison below 6000ft-
Gallatin Valley-Madison River Valley-Missouri Headwaters.

Winter Storm Warning from 6 AM to 6 PM MDT Thursday for Snowy
and Judith Mountains.
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$$

http://www.weather.gov/greatfalls