292
FXUS65 KTFX 161801
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1200 PM MDT Sun Jun 16 2024

.SYNOPSIS...

Gusty west winds along the Rocky Mountain Front and Plains
continue through the morning. Widespread precipitation bringing
mountain snow and lower elevation rain arrives Sunday night and
lasts through Tuesday evening. Below average temperatures
forecasted for Monday and Tuesday. Temperatures gradually warm up
through the rest of the week. Daily low chances for precipitation
remains through the week.

&&

.UPDATE...

With this update, I`ve expired the High Wind Warning, with a note
that strong gusty winds continue and decrease throughout the day.
Additionally, I`ve touched the wind speed/gust forecast, to bring
the forecast in line with observed conditions. Aside from these
adjustments, no noteworthy changes are made.
- Fogleman

&&

.AVIATION...
16/18Z TAF Period

VFR conditions are expected to prevail through midnight or so across
North Central and Southwestern Montana, with some gusty winds from
KHLN north. Expect clouds to gradually thicken today, with MVFR cigs
beginning to become possible around/after midnight with rain and
mountain snow developing. After midnight, expect periods of MVFR to
IFR conditions as low cigs and rainfall spread across North Central
and Southwestern Montana, along with mountain obscuration. Ludwig

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

&&

.PREV DISCUSSION...
/ISSUED 456 AM MDT Sun Jun 16 2024

Today through monday...Water vapor satellite shows mountain wave
activity producing strong winds along the Rocky Mountain Front.
High winds across the Rocky Mountain Front and and plains continue
through the morning hours as High Wind Warning for the Rocky
Mountain Front is set to expire by 9am. Be prepared for strong
crosswinds if traveling this morning.

A surface front swinging down from Canada will create
some light showers along the northern Hi-Line/Rocky Mountain Front
region this morning ahead of the main system moving in later in the
day. Energy from this upper level trough will move into the region
during the evening hours, bringing in lower elevation rain and
snow for elevations generally above 6,000ft. Precipitation will
become more widespread and heavier Monday morning with the upper
level low moving passing through the region. There may be a few
embedded thunderstorms with precipitation on Monday/Tuesday
afternoon due to a little amount of instability present.
Precipitation lingers into Tuesday along another wave of passing
through the region. Snow probabilities in the mountains are
between 30-50% for exceeding 8" of snow. Considering the bulk of
the snow being above pass level and probabilities for
accumulations to reach winter warning criteria (9 inches) remain
on the lower side, I have opted to transition the Winter Storm
Watches for mountain zones into Winter Weather Advisories.
Another change I`ve made to the winter highlights is to move up
the timing to 6pm Sunday to 6pm Tuesday to account for the earlier
start and end times for precipitation. Greatest QPF amounts look
to set up across Central MT, where they hav.DISCUSSION...
e around a 50% of
exceeding 1". Most other lower elevations across the CWA have at
least a 50% of exceeding 0.25". In terms of possible higher end
QPF amounts, the 75th NBM percentile ranges between 1.25-1.5"
across Central MT and 0.35-0.75" across most other lower
elevations.

With the upper level low bringing down colder air, cold overnight
temperatures are forecasted for Monday and Tuesday morning.
Tuesday morning wind chills in the mountains can drop down to the
teens and 20s. Those in the backcountry should prepare for
cold/raw conditions.

Wednesday and looking beyond...The main upper level low will move
off to the east, and a zonal/southwest flow aloft pattern will
settle in behind for the remainder of the week. There looks to be
enough moisture around and small disturbances that passes through to
keep low chances of precipitation daily. With the southwest flow
aloft bringing in warmer air, temperatures will gradually warm up
through the weekend. By Saturday, lower elevations have a 60-80% of
high temperatures reaching 80 degrees or higher. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  66  42  50  40 /   0  40 100  80
CTB  59  36  54  37 /  30  10  70  50
HLN  68  43  53  41 /   0  50 100  80
BZN  67  41  55  36 /   0  30 100 100
WYS  61  38  51  30 /   0  10  70  70
DLN  65  38  51  34 /   0  40 100  60
HVR  63  42  57  42 /  30  10  80  60
LWT  63  38  50  35 /   0  30 100 100

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 PM this evening to 6 PM MDT
Tuesday for Big Belt, Bridger and Castle Mountains-East Glacier
Park Region-Elkhorn and Boulder Mountains-Gallatin and Madison
County Mountains and Centennial Mountains-Little Belt and
Highwood Mountains-Northwest Beaverhead County-Southern Rocky
Mountain Front.

&&

$$

http://www.weather.gov/greatfalls