Straw, Montana Weather Forecast Discussion

617
FXUS65 KTFX 172308
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
508 PM MDT Wed Sep 17 2025
Aviation Section Updated.
.KEY MESSAGES...
- Mainly dry conditions with increasingly warmer temperatures
   are expected through Saturday.
- Windy conditions develop Saturday night through Sunday with
   strong winds possible along the Rocky Mountain Front.
- Scattered precipitation and more seasonal temperatures develop
   late Sunday through Monday before warming again early next
   week.
&&
.DISCUSSION...
/Issued 136 PM MDT Wed Sep 17 2025/
- Meteorological Overview:
A narrow, positively tilted upper-level ridge currently stretching
from the interior Northwestern U.S. into Alberta will weaken over
the rest of the work week. A shortwave moving across southern
British Columbia and Alberta late Friday will cause a broader
upper-level ridge to shift east of the Northern Rockies this
weekend. This will lead to relatively mild weather through the
first part of the weekend, with temperatures rising above seasonal
averages and peaking on Saturday. Surface high pressure east of
the Rockies will keep winds light through Friday. Breezy winds
will develop on Saturday as a lee-side trough forms east of the
Rockies and the upper ridge axis shifts eastward. A larger-scale
Pacific upper trough will move into western Canada late this
weekend, with surface low pressure tracking east across central
Alberta on Sunday. This system will drag a Pacific cold front east
across the Northern Rockies late Sunday, likely bringing the
first "fall-like" wind event of the season. A moderate to strong
pressure gradient across the Rockies and westerly mid-level flow
of 40-50 knots will support widespread windy conditions, with
potential for strong winds along and near the Rocky Mountain
Front. Precipitation with this system will likely be scattered for
most areas and primarily occur after the frontal passage.
Temperatures will cool slightly but remain above seasonal averages
Sunday and Monday. Long-range models support a return to upper-
level ridging and above-average warmth behind this system early
next week.
- Forecast Confidence & Scenarios:
Lingering surface moisture from recent precipitation will likely
keep dew points somewhat elevated through Friday, potentially
leading to patchy fog development tonight in areas with light
winds. This moisture will also contribute to daily afternoon
cumulus development, and an isolated shower or thunderstorm
cannot be ruled out, mainly across the island ranges of north-
central Montana.
The probability of wind gusts exceeding 55 mph on Sunday is
greater than 50% only for areas along the immediate east slopes of
the Rocky Mountain Front and Glacier National Park. There is up
to a 20% probability for gusts of this magnitude as far east as
Cut Bank. A 20-40% probability exists for wind gusts to exceed 45
mph across much of north-central Montana. Therefore, High Wind
products are not being considered at this time. However, this is
notable as the first event of its type for the season, with
potential for additional impacts from remaining deciduous tree
foliage and to those unaccustomed to driving in stronger cross-
winds. Hoenisch
&&
.AVIATION...
18/00Z TAF Period
Most locations will see clear skies and VFR conditions for the
duration of this TAF period; however, a retrograding mid- level
low, currently over southern SK, will bring MVFR/IFR stratus and
patchy fog to the KHVR area between 18/09 and 18/18Z. Also,
continued high surface moisture and light winds will result in a
return of patchy fog development over the central and southwest
valleys (KBZN, KHLN, and KWYS) tonight, mostly between 18/09 and
18/15Z. - RCG
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF  47  79  47  80 /   0   0   0   0
CTB  43  76  44  76 /   0   0   0   0
HLN  48  80  49  81 /   0   0   0   0
BZN  42  78  44  79 /   0   0   0   0
WYS  30  70  32  73 /   0   0   0   0
DLN  41  77  43  77 /   0   0   0   0
HVR  46  74  46  77 /   0   0   0   0
LWT  46  74  44  75 /   0  10   0   0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls

NWS TFX Office Area Forecast Discussion