Helena Valley West Central, MT 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

396
FXUS65 KTFX 181709
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1109 AM MDT Wed Jun 18 2025

Aviation Section Updated.

.KEY MESSAGES...

- Fairly quiet conditions today, mainly warm, with low humidity.

- Still warm on Thursday, but thunderstorms develop by mid
  afternoon. Some storms could be severe.

- Thunderstorms are more widespread on Friday, again with an
  isolated severe storm. Some storms could also produce heavy
  rainfall.

- A short but impactful cold snap expected for Saturday and Sunday
  bringing widespread lower elevation rainfall and mountain
  snowfall.

- A return to more June like conditions by the middle of next
  week.


&&

.UPDATE...
/Issued 1017 AM MDT Wed Jun 18 2025/

Morning update has been published, with the primary change being
the addition of a Winter Storm Watch for the East Glacier Park
Region from Saturday afternoon through Sunday afternoon. Otherwise
the near-term forecast remain on track, with minimal changes made.
- Moldan

&&

.DISCUSSION...
/Issued 1017 AM MDT Wed Jun 18 2025/

 - Meteorological Overview:
A shortwave upper level ridge will build over the CWA today,
resulting in quiet but warm conditions.

On Thursday...the flow aloft becomes more southwest by the
afternoon, as upper level disturbances approach the CWA from the
Southwest. This will lead to scattered showers/thunderstorms
developing over Southwest and eventually Central MT by the late
afternoon hours. There will be enough instability for an isolated
severe storm.

For Friday...expect the southwest flow aloft to continue as the
main upper level low approaches from the west. There is the
potential for severe storms on Friday across the entire CWA.
However, cloud cover and morning precipitation could lower the
threat for severe storms over the western portions of North
Central MT a bit. Additionally, a cooling trend will begin on
Friday, with afternoon temperatures not quite as warm. The
moisture in the airmass will also increase to over one inch. This
will allow for the potential for some storms to produce heavy
rainfall, with the areas along the Highway 2 corridor from
Browning to Havre the most favored area at this time for heavy
rainfall.

For Saturday and Sunday...it will be officially summer by this
time, so a summer storm that is likely to produce winter
conditions is expected to affect the CWA during this period. Snow
levels will lower Saturday and Saturday night across the CWA, with
Sunday morning likely being the coldest period. Snow levels could
lower to around 5000 feet over the northern portions of the CWA.
Snowfall amounts could be impactful along the Rocky Mountain
Front, especially in Glacier Park. Overall, temperatures will be
well below normal across the entire CWA during this period.

For Monday through Wednesday, expect a nice warming trend with the
chances for precipitation becoming more isolated during this
period.

 - Forecast Confidence & Scenarios:

Low humidity, warm temperatures and breezy winds will create some
areas of elevated fire weather conditions today and Thursday.
However, conditions do not look widespread or last long enough for
a fire weather highlight at this time.

Some storms could produce strong wind gusts or large hail Thursday
and Friday. However, some of the higher resolution models are not
showing the wind gusts quite as strong as earlier thought.
Additionally, cloud cover on Friday could limit the area that
could be impacted by any severe storms.

Additionally, with precipitable water on the high side Friday,
some storms could produce heavy rainfall, or possible flash flood
conditions. Thus portions of the hi-line are in a marginal risk at
this time.

Snowfall for Saturday and Sunday is looking impactful in Glacier
Park. There is a 60 percent chance snowfall could exceed 6 inches
of snow for elevations above 6000 feet. Winter statements for this
event are looking more likely, and could be issued as early as
later today.



&&

.AVIATION...
18/18Z TAF Period

VFR conditions will prevail across all terminals during this TAF
period with scattered to few high-level clouds around. At all but
the KBZN terminal there will be gusty winds around during at
least a portion of this TAF period. Across North-central Montana
during the beginning of this TAF period there will isolated
instances of low-level wind shear and mountain wave turbulence.

The one exception to VFR conditions will be for areas near Helena
because of the Jericho wildfire, which is about 10 miles due west
of the Helena airport. This wildfire could produce columns of
smoke at times that could impact the Helena airport on short
notice. IG/Brusda

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  84  50  85  54 /   0   0  10  60
CTB  81  49  79  50 /   0   0   0  30
HLN  86  52  85  55 /   0   0  20  50
BZN  85  47  88  52 /   0   0  20  40
WYS  74  37  82  42 /   0   0  10  30
DLN  82  45  86  50 /   0   0  20  30
HVR  85  54  85  55 /   0   0   0  40
LWT  77  49  80  52 /   0   0  10  70

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Saturday afternoon through Sunday
morning for East Glacier Park Region.

&&

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