753
FXUS65 KTFX 060221
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
821 PM MDT Fri Jun 5 2026

.KEY MESSAGES...

 - Scattered showers and thunderstorms on Saturday then turning
   much cooler with additional showers Sunday.

 - Breezy conditions through the weekend, particularly along the
   Rocky Mountain Front and across Southwest Montana.

 - An active pattern is expected next week with daily chances for
   precipitation starting Tuesday.

&&

.UPDATE...

Southwest flow aloft advecting in warm, moist air has developed
isolated light showers in North-Central MT on radar. It seems,
with a dry surface layer this may be mostly virga. I did add low
end PoPs this evening and Saturday morning in case a few light
showers make it to the ground. -Wilson

&&

.DISCUSSION...
/Issued 607 PM MDT Fri Jun 5 2026/

 - Meteorological Overview:

A low-amplitude upper level ridge transits the Northern Rockies and
MT today bringing the warmest and driest conditions of the next
seven days before an  upper level low/trough, currently offshore
of BC moves into the NW US this weekend. Breezy west to southwest
winds develop today as flow aloft shifts more southwesterly behind
the exiting upper ridge with gusts in excess of 35 mph primarily
confined to areas along the Rocky Mtn Front as the surface pressure
gradient across the Rockies increases today and over portions of SW
MT where deeper afternoon mixing is achieved.

A Pacific cold front crosses the Northern Rockies Saturday with
moisture gradually increasing within the southwest flow aloft. A few
showers develop behind the front across north-central/central MT
early Saturday with showers and a few thunderstorms tracking
northeast from southwest MT Saturday afternoon through eastern
portions of north-central MT Saturday evening.

A stronger shortwave rotates through the trough across the Rockies
Saturday night through Sunday, spreading much cooler temperatures
across the area along with more widespread showers and perhaps a few
thunderstorms. Snow levels fall to around 7000 ft Sunday and
potentially as low as 6000 ft with the coldest air aloft passing
across the area Sunday afternoon. This could bring some snow as low
as passes across central and southwest MT, however afternoon timing
will limit the potential for accumulation. Gusty west winds and
afternoon temperatures in the 50s (upper 30s/40s in the mountains)
on Sunday may impact those with outdoor recreation plans in the
mountains. Clearing is expected Sunday night as the trough lifts out
of the area with overnight low temperatures reaching the 30s to
around 40 across most of the forecast area.

A fairly active/unsettled weather pattern persists next week with
mainly dry conditions and seasonable warmth Monday before the
next larger scale upper trough/low drops into the western US for
the remainder of the week. While there is good overall agreement
on the broader trough and increasing confidence in widespread
precipitation, there is still a fair amount of variation in timing
and placement of the upper low with probabilities for 0.50" or
greater precipitation amounts (Tues-Thurs) ranging from 50-70%
across much of the area. Hoenisch

 - Forecast Confidence & Scenarios:

Thunderstorms Saturday:

For our CWA, the highest instability will be across Southwest
Montana into portions of Central Montana as far north as Fergus
county. The 18Z HRRR suggested CAPE was less than 800 J/kg in the
region which is enough to do something but not enough to create
significant problems. One or two storms might attempt to misbehave
but in general most of the activity is expected to stay on the
low-end of things.


Precipitation Sunday:

More widespread precipitation is expected on Sunday. The highest
probabilities for greater than a tenth of an inch lie south and
east of a line between Havre to Great Falls to Missoula. For
locations in central Montana such as the Little Belts, there is a
90% chance of at least 0.25" and a 75% chance of at least 0.5".
Widespread flooding is not expected with this event, however,
there is a possibility for some creeks might rise and low-lying,
flood-prone areas might have some ponding. But there is no larger
risk at this time. This will be monitored in case anything
changes.

In terms of snow, there is still some uncertainty as to how much
will be able to accumulate. Right now, snow levels are expected to
drop to around 6,000-8,000 feet which will allow for at least a
dusting across much of the higher elevations. But finding amounts
greater than 2 inches will be a challenge as

As to whether locations below 6,000 feet might see snow that is
still up for debate. With the timing of the precipitation still
expected to be Sunday afternoon, it is unlikely that any of the
valleys of Southwest Montana will see snow, however, it is not
completely out of the realm of possibilities either. With this
forecast package, snow levels went down slightly but not enough to
increase confidence and the going thought is that, even if a
couple flurries end up falling, it is highly unlikely there will
be accumulating snow at or below pass level. But given the
uncertainty, there is still always a chance that things could
change from now until Sunday.  -thor


&&

.AVIATION...
05/18Z TAF Period

VFR conditions are expected to generally prevail over the next 24
hour period, with generally clear skies and winds decreasing this
evening. A few SHRA and TSRA will be possible tomorrow afternoon,
particularly around KLWT and KHVR, but there is not currently
enough confidence in timing/coverage to include in TAFs. Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  49  72  45  57 /  10  20  50  70
CTB  44  65  39  57 /  20  30  10  30
HLN  49  74  45  57 /   0  30  50  80
BZN  46  79  43  61 /   0  20  60  90
WYS  39  76  40  61 /   0  10  30  40
DLN  46  78  43  59 /   0  20  50  70
HVR  48  76  45  63 /  20  20  50  50
LWT  46  76  42  56 /  20  20  70  90

&&

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

$$
http://www.weather.gov/greatfalls