608
FXUS65 KTFX 141803
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1159 AM MDT Fri Jun 14 2024

Aviation Section Updated

.SYNOPSIS...
Showers and thunderstorm chances return this afternoon with the
small chance for a few severe wind gusts and small hail in Southwest
Montana. Windy conditions expected along the Rocky Mountain Front
this weekend, along with light precipitation across the region.
Better chances for widespread precipitation and mountain snow return
Monday and Tuesday. Below average temperatures expected beginning of
next week, but will warm up mid week.

&&

.UPDATE...
Aside from a few isolated rain showers this morning (and rumbles of
thunder in the Gallatin Valley), expect mostly sunny skies across
the area with a few isolated thunderstorms across Southwestern
Montana this afternoon. Looking ahead, next week`s system is showing
some uncertainty, which will result in some changes to the forecast
for this system with the afternoon forecast package, especially
across the plains. Ludwig

&&

.AVIATION...
14/18Z TAF Period

Quiet conditions will start the period, but do expect thunderstorms
to develop after 21z over Southwest MT, then spread northeast into
the Bozeman and Lewistown areas towards evening. Some storms could
produce some hail and gusty winds. Expect another band of showers to
develop after 10z Saturday ahead of a cold front that will move west
to east across the CWA on Saturday. Gusty winds will develop behind
the cold front on Saturday afternoon. Mountains/passes will be
obscured at times by showers/thunderstorms. Brusda

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

&&

.PREV DISCUSSION...
/ISSUED 500 AM MDT Fri Jun 14 2024/

Today...Some early morning showers will continue to move across
primarily Southwest Montana. A dynamic upper level trough moving
east into the weekend will bring an active pattern through mid
next week. A small upper level shortwave moving through will spark
scattered showers/storms long a front across MT shortly after
noon. The Storm Prediction Center has put southeastern
Beaverhead/Madison Counties and Southern Gallatin County in a
marginal risk for a 5% chance of severe storms containing gusty
winds and small hail. Most of the lower elevations will experience
one last day of 80s temperature before colder air moves in over
the weekend.

Saturday and Sunday...Colder air moves in for the weekend behind
the front. Another upper level disturbance moving through the
region will bring more light showers/thunderstorms to the region
Saturday morning and afternoon. Additionally, stronger winds
aloft will bring windy conditions to the Rocky Mountain Front
between Saturday afternoon and Sunday. There`s a 50-60% chance of
the Continental Divide of exceeding 64mph wind gusts. There`s a
70% chance the Cut Bank area can exceed 55mph wind gusts.

Monday through Tuesday...An upper level low will move east across
the region, bringing in a more dynamic weather system to the CWA.
There`s a 40-70% chance of lower elevations exceeding 0.50" of
QPF Monday and Tuesday. Higher QPF amounts are possible at the
higher elevations. Higher elevations have a 50% chance of
exceeding 1" of QPF and a 20% of exceeding 2". Snow levels will
fall below 7,000ft and can fall to slightly below 6,000ft at times
depending on how much cold air funnels down. As a result, heavy
wet snow will impact the higher elevations, which has prompted the
Winter Storm Watches. There`s a 40-60% chance of locations in the
watch exceeding 6" of snow. Given snow probabilities are similar
to the Southwest MT mountains, and higher QPF amounts are
concentrated along the Belts and Little Belts region, I have opted
to include them in the Winter Storm Watch for the same time
frame. Heavy wet snow can weigh down tree limbs and power lines,
and can cause hazardous conditions in the backcountry. With the
colder air moving in, temperatures for Monday and Tuesday will see
below average temperatures. Overnight lows will drop below
freezing at higher elevations.

Wednesday and beyond...The upper level trough will move out of
the area brining warmer and drier conditions. Although, a few
disturbances will try to bring low end precipitation chances
during this time frame. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  85  52  72  43 /  20  20  50   0
CTB  78  46  64  41 /   0   0  30   0
HLN  87  54  74  42 /  20  20  40   0
BZN  85  50  77  37 /  30  40  40  10
WYS  77  44  69  35 /  40  20  10   0
DLN  84  50  73  34 /  20  20  10   0
HVR  85  52  75  45 /  20  10  50  20
LWT  80  49  75  38 /  20  50  70  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Saturday afternoon through late Saturday
night for Eastern Glacier, Western Toole, and Central Pondera-
Northern High Plains.

Winter Storm Watch from Monday morning through Tuesday evening
for East Glacier Park Region-Southern Rocky Mountain Front.

Winter Storm Watch from Monday evening through Tuesday evening
for Big Belt, Bridger and Castle Mountains-Elkhorn and Boulder
Mountains-Gallatin and Madison County Mountains and Centennial
Mountains-Little Belt and Highwood Mountains-Northwest
Beaverhead County.

&&

$$

http://www.weather.gov/greatfalls