Helena Valley West Central, MT 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

692
FXUS65 KTFX 290005
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
605 PM MDT Sun Jun 28 2026

Aviation Section Updated.

.KEY MESSAGES...

 -  Snow in the terrain continues across Southwest Montana and
   vicinity through Monday morning.

 - Gusty winds over the plains through the early overnight, peaking
   early evening.

 - Moderate to briefly heavy rain develops through the remainder
   of the day in many areas, particularly for areas along and
   west of I-15 on the plains.

 - Impactful weather diminishes Monday evening and Monday night, though
   the risk for afternoon and evening showers and thunderstorms
   will persist through much of the upcoming week.

&&

.DISCUSSION...
/Issued 200 PM MDT Sun Jun 28 2026/

Broad upper level troughing with a couple embedded upper level lows
will continue to result in impactful weather across the Northern
Rockies over the next 36 hours or so. One of the initial and ongoing
concerns is for mountain snow, mainly at and above pass level,
across Southwest Montana and vicinity. This portion of the region is
closest to the colder of the two upper level lows, which is allowing
for snow levels to drop quite a bit south of I-90. Webcam imagery in
Southwest Montana at Big Hole Pass indicates snow levels continue to
be near or below 6,500ft. After another push of snow tonight, snow
begins to taper through Monday morning.

The second, and warmer of the two upper level lows is pivoting back
westward from far SW SK toward the region this afternoon. This
portion is nearly stacked with surface and mid level low pressure
that is slowly nudging southward toward the International Border
near Hill county and vicinity. Given these being nearly stacked, the
surface low pressure that is approaching has nearly peaked in
intensity and looks to do so early this evening. Strong winds near
the surface pivoting around the west, south and southeast portions
of this surface low look to be mixed to the surface this afternoon
and evening across portions of the plains. A High Wind Warning is in
effect for areas where confidence is greatest in impacts being
realized. These winds subside late evening and early overnight as
the surface low quickly fills.

All the while, northerly to northeasterly winds through the lower to
mid-levels will combine with forcing from the troughing across the
region to result in another stretch of widespread precipitation
through Monday. Precipitation through the afternoon today pivots
southward from SW AB into the region and becomes more widespread
through the evening and overnight. Given this is the warmer portion
of this system, snow levels further north are quite high. Thus
concerns for any mountain snow look to be primarily south of the US-
12 corridor. Precipitation amounts look greatest near Glacier NP,
where northerly to northeasterly mid-level will be most orthogonal
to terrain. Those with interests in and near Glacier NP should be
aware of the risk for rockfall and creek and stream rises through
Monday. Precipitation rates in this area look to peak this evening
into the early overnight.

Although this system departs heading into Tuesday, upper level
troughing remains across much of the west through the week.
Temperatures trend warmer, but afternoon and evening showers and
thunderstorms will be around most days this week. At this point
there does not look to be much shear around, which keeps confidence
low in any organized severe thunderstorms through this week. -AM

&&

.AVIATION...
29/00Z TAF Period

Wet and breezy conditions are found across North Central Montana
terminals (KGTF, KLWT, KHVR, KCTB) this evening as a band of
heavier wind and rain pivot through the area from the north.
Expect MVFR to IFR conditions to prevail through much of the
overnight across the plains as precipitation moves through and
ceilings lower. SW MT terminals (KBZN, KWYS, KEKS, KHLN) will
generally remain MVFR this evening, but some IFR conditions due to
lower ceilings will arrive overnight tonight. Precipitation
remains fairly persistent across SW MT after 12z, but becomes more
showery across the plains allowing for some opportunities for VFR
conditions. Ludwig

&&

.HYDROLOGY...
Periods of rain will continue to affect the CWA from today
through Monday. Widespread rainfall amounts of 1 to 3 inches are
still expected by Monday.

In the Glacier Park region, rainfall is expected to be a bit
heavier, possibly up to 4 inches. Additionally, with some high
elevation snow still left, the combination of rainfall/snowmelt
could lead to some flooding on the east side of Glacier National
Park. Thus a flood watch has been issued for this region starting
on Sunday. Should later forecast today decrease the projected
rainfall amounts, the flood watch might be cancelled.

Additional flood statement might be needed if rainfall amounts
start to exceed 3 inches elsewhere across the CWA. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  58  48  72 / 100  90  90  40
CTB  47  59  48  68 / 100  90  90  50
HLN  44  56  47  71 / 100 100  80  60
BZN  39  54  42  69 /  90  90  60  30
WYS  28  47  32  62 /  80 100  70  20
DLN  36  55  39  67 / 100  90  40  30
HVR  45  65  48  73 /  90  70  70  70
LWT  41  55  44  68 /  50  80  80  60

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until midnight MDT tonight for Eastern Toole
and Liberty.

Flood Watch through Monday evening for East Glacier Park Region.

High Wind Warning until 3 AM MDT Monday for Bears Paw Mountains
and Southern Blaine-Hill County-Western and Central Chouteau
County.

Winter Weather Advisory until noon MDT Monday for Elkhorn and
Boulder Mountains-Gallatin and Madison County Mountains and
Centennial Mountains-Ruby Mountains and Southern Beaverhead
Mountains.

Winter Storm Warning until noon MDT Monday for Northwest
Beaverhead County.

&&

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