461
FXUS65 KTFX 301606
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1006 AM MDT Thu May 30 2024

.SYNOPSIS...

Today fog could form in the West Yellowstone area and
along the Idaho border in Southern Southwestern Montana. Today an
upper-level disturbance will bring rain showers to the eastern
portion of the Hi-Line. It will be windy along the Rocky Mountain
Front today. Unsettled weather will continue through at least
Tuesday with a warm up possible for the middle of next week.

&&

.UPDATE...

Just a few minor changes this morning. First, I updated the hourly
temperatures as usual to account for this morning`s lows. I also
ensured that showers were in the forecast at all plains locations,
as there were a few locations where the POP was just a little too
low for it to be mentioned in the forecast before. Ludwig

&&

.AVIATION...

30/12Z TAF Period

VFR conditions are expected to continue through at least 31/06Z
across North Central (KCTB, KHVR), Central (KLWT, KGTF, KHLN), and
Southwest (KBZN, KEKS, KWYS) Montana, unless otherwise noted.

Areas of mid- and high-level cloudiness will move over the area in a
moderate northwest flow aloft through at least 03Z. Patchy fog in
some southwest valleys (including KBZN KWYS) could reduce conditions
to MVFR between 12Z and 16Z, but the cloud cover there is making it
less likely for this significant reduction to occur. The winds aloft
will cause mountain wave turbulence through the period, as well as
some low level wind shear (mainly over North Central and Central
Montana) until the increasing westerly surface winds mix down to the
surface again after 14Z. A disturbance in the flow aloft will bring
a chance of showers to portions of North Central Montana (mainly in
the KCTB and KHVR areas between 18Z and 00Z. Winds and clouds should
generally decrease after 01Z. -Coulston

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

&&

.PREV DISCUSSION...
/ISSUED 535 AM MDT Thu May 30 2024/

Today through Friday... Today there is an upper-level
trough in place over North-central, Central, and Southwestern
Montana. This will keep temperatures cool. This morning in the West
Yellowstone area and isolated other locations of Southern
Southwestern Montana near the Idaho border fog could form due to the
precipitation that fell today and light winds. Late this morning
through this afternoon an upper-level disturbance will move along
the Hi-Line and bring rain showers to the central and eastern
portion and areas just south of the Hi-Line. Today there is a 20 -
40% chance for locations along the central and eastern portion of
the Hi-Line south to Fort Benton receiving a tenth of an inch of
rain (total liquid amount for mountain locations) or more. Today for
the mountains of North-Central, Central, and Southwestern Montana
there is 20 - 60% chance for receiving a tenth of an inch of snow or
more. Today due to a strong surface pressure gradient along the
Rocky Mountain Front there is a 60 - 80% chance for wind gusts
exceeding 55 mph. Today along the plains adjacent to the Rocky
Mountain Front and across isolated locations of Central and North-
central Montana there is a 50 - 80% chance for wind gusts
exceeding 47 mph. On Friday the upper-level trough slowly begins
to move to the east away from North-central, Central, and
Southwestern Montana. This will allow temperatures to warm up to
near seasonal averages on Friday. Friday morning across the lower-
elevations of Southwestern Montana there is the potential for
frost to form, but if it forms it will melt quickly. On Friday it
will be dry across the area.

Saturday through Monday... On Saturday a weak upper-level ridge
moves over North-central, Central, and Southwestern Montana. This
will warm up temperatures and keep most of North-central and Central
Montana dry with precipitation chances (10-20%) south of the Montana
Highway 200 Corridor Saturday afternoon and evening. On Sunday
across North-central, Central, and Southwestern Montana there will
be mostly zonal flow with a few upper-level disturbances before an
upper-level ridge begins to move into the area Sunday evening. This
will bring a 10 - 20% chance for a tenth of an inch of rain to
Southwestern Montana early Sunday morning through Sunday evening. On
Monday the upper-level ridge remains in place over North-central,
Central, and Southwestern Montana. On Monday due to strong upper-
level flow there will be strong wind gusts along the Rocky Mountain
Front and adjacent plains and in isolated locations of Southwestern
Montana. There is a 60% chance for locations along the plains
adjacent to the Rocky Mountain Front and in isolated locations of
Southwestern Montana having wind gusts exceeding 47 mph. On Monday
along the Rocky Mountain Front there is a 50 - 80% chance for wind
gusts exceeding 55 mph. This will need to continue to be monitored.
Monday afternoon and evening there is 20% chance for a tenth of inch
of rain for the lower-elevations of North-central, Central, and
Southwestern Montana.

Tuesday through next Thursday... On Tuesday clusters indicate that a
weak upper-level trough will move over North-central, Central, and
Southwestern Montana. This indicates that unsettled weather will
continue for Tuesday across the area. On Wednesday three clusters
(76% of ensemble members) indicate that an upper-level ridge moves
back over North-central, Central, and Southwestern Montana. The
other cluster (24% of ensemble members) keeps the upper-level trough
over North-central, Central, and Southwestern Montana. This
indicates that unsettled weather could continue for Wednesday or it
could be warm and dry across the area. Next Thursday clusters have
an upper-level ridge over North-central, Central, and Southwestern
Montana. Two of the clusters (72% of ensemble members) have a
stronger ridge. This indicates that temperatures could warm back up
to above seasonal averages. This will need to continue to be
monitored. -IG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  62  38  67  41 /  10   0   0   0
CTB  60  38  64  39 /  30   0   0   0
HLN  63  39  71  44 /  10   0   0   0
BZN  60  33  68  38 /  10   0   0   0
WYS  53  29  62  32 /  10   0   0   0
DLN  58  33  68  38 /   0   0   0   0
HVR  62  41  67  41 /  40  10  10   0
LWT  57  35  62  39 /  20   0   0   0

&&

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

$$

http://www.weather.gov/greatfalls