691
FXUS65 KTFX 221154
AFDTFX

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

...Aviation Section Update...

.SYNOPSIS...

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.

&&

.DISCUSSION...

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 during the issuance of this forecast.
The probability of snow amounts exceeding 6 inches, is at 80% or
more across our mountain zones. Heavy wet snow may cause damage to
trees and power lines. 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. Travel will
be dangerous across some mountain passes. 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 in moisture. With temperatures warming, most moisture from
the ongoing active weather pattern, falls as rain. having said this,
some mountain snow is forecast, and concerns for those wishing to
recreate in the outdoors over the Memorial Day Weekend, continues.

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

&&

.AVIATION...
22/12Z TAF Period

Note: The NWS Great Falls Weather Forecast Office manages the
following TAFs: KCTB, KHVR, KGTF, KLWT, KHLN, KBZN, KEKS and KWYS.

All TAFs begin under degrading VFR conditions. The next system
arrives through the day, today. Conditions, ultimately, become
MVFR/IFR/LIFR at all airfields. The initial concern is for lower
elevation rain showers and scattered thunderstorms with higher
elevation snow showers through daylight hours. Snow levels fall down
as low as valley floors at times, tonight. Expect mountain
obscuration.
- Fogleman

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

&&

.HYDROLOGY...

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.

&&

.PRELIMINARY POINT TEMPS/POPS...
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

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
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.

&&

$$

http://www.weather.gov/greatfalls