Helena Valley, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

781
FXUS65 KTFX 290550
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1150 PM MDT Sun Jun 28 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Higher terrain snow will continue in Southwest Montana through
   this morning.

 - Consistent rainfall will continue today across Southwest,
   Central, and North-Central Montana, decreasing tonight before
   dissipating early tomorrow morning.

 - Daily chances for showers and thunderstorms throughout the rest
   of the week.

&&

.DISCUSSION...

 - Meteorological Overview:

A large upper level trough with multiple embedded upper level
lows will continue to create impactful weather across the CWA
today. Northerly to northeasterly winds through the lower to mid-
levels will combine with forcing from the troughing across the
region to result in continued widespread precipitation today. This
stratiform rain will persist through tonight into early tomorrow
morning. Mountain snow will continue in Southwest Montana through
late this morning. 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 tomorrow morning.

The upper level trough moves out of the CWA tomorrow, ending the
persistent stratiform rain. However, there will be daily chances
for showers and thunderstorms throughout the rest of the week, as
instability in the atmosphere persists. Despite this, shear
remains low at this time, inhibiting the development of severe
thunderstorms. Temperatures will have a warming trend, peaking
early next week with highs in the mid to high 80s with the
building of an upper level ridge. - AM and Dzomba


&&

.AVIATION...
29/06Z TAF Period

Widespread rain and high mountain snow will affect much of the CWA
through the period. Expect the precipitation to slowly begin to
diminish after 00z Tue over Southwest MT and the eastern portions
of the CWA. Strong surface winds over North Central MT should
decrease a bit by 12z Mon. Mountains/passes will be obscured
across the CWA through the period. Brusda

&&

.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  50  74 / 100 100  90  20
CTB  47  60  49  71 / 100  90  90  20
HLN  44  58  49  72 / 100 100  80  50
BZN  39  54  44  71 / 100 100  70  30
WYS  28  47  32  63 /  90 100  50  10
DLN  36  55  40  68 / 100 100  30  50
HVR  45  63  50  76 /  90  80  70  40
LWT  41  54  45  70 /  60 100  80  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
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