Roy, Montana Weather Forecast Discussion

007
FXUS65 KTFX 161102
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
Issued by National Weather Service Glasgow MT
502 AM MDT Tue Sep 16 2025
Aviation Section Updated.
.KEY MESSAGES...
- Showers and a few thunderstorms begin to move off to the east
   late today.
 - Trending warmer Wednesday, with dry conditions persisting into
   at least Friday.
 - Uncertainty in specifics increases for the weekend, but a brief
   period of gusty winds is increasing in likelihood over the
   plains.
&&
.DISCUSSION...
- Meteorological Overview:
An upper level low has stalled over portions of MT into WY this
morning. Cool temperatures aloft and forcing from the low has
allowed for elevated showers and isolated thunderstorms to
continue over portions of Southwest and Central Montana as of
writing this discussion. Light showers may persist through the
morning in Southwest Montana before another round of afternoon and
early evening showers and thunderstorms develop, mostly across
portions of Central and Southwest Montana.
The upper level disturbance drifts far enough away for Wednesday
to allow for a drying and warming trend. The region looks largely
dry through Friday ahead of a series of waves within a larger
scale trough across the far western CONUS that may arrive this
weekend.
Confidence in how this pattern evolves is low, with several waves
interacting with each other before ejecting east or northeast
toward the Northern Rockies, if they do at all. There are several
scenarios that result in brief shots of precipitation this
weekend, while there are many that keep the region dry. The
common theme between all of these scenarios is for a brief period
of gusty winds later in the weekend as a more zonal flow develops.
Heading into early next week, guidance converges a bit on broad
ridging across the west. Though this is the case, flow over the
Northern Rockies is largely zonal, which keeps the window open
for breezy winds on the plains. -AM
- Forecast Confidence & Scenarios:
Winds this weekend: Whether or not there is weak ridging or
troughing in place to open the weekend, guidance is converging on
a zonal flow solution heading into Sunday. This lends to increased
confidence in gusty winds Sunday. As it stands, there is a roughly
50% chance for a gust of 50 mph between Cut Bank and Browning
Sunday. -AM
&&
.AVIATION...
16/12Z TAF Period
MVFR/VFR conditions will prevail through 16/21z to 17/03z as a slow
moving disturbance gradually pulls away from the Northern Rockies,
with VFR conditions expected thereafter as precipitation decreases
from northwest to southeast across North Central through Southwest
Montana. Scattered to numerous showers, with isolated thunderstorms,
will be most common south and east of a KEKS, to KGTF, to KHLN, to
KWYS line through the morning and afternoon hours today. Mountains
will be obscured through the evening hours tonight. - Moldan
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF  73  46  78  46 /  30   0   0   0
CTB  73  42  77  42 /  10   0   0   0
HLN  72  48  77  48 /  50  10   0   0
BZN  66  42  74  42 /  70  10   0   0
WYS  60  31  68  30 /  50  10  10   0
DLN  66  41  71  40 /  20   0   0   0
HVR  77  45  78  45 /  10   0   0   0
LWT  67  46  73  45 /  60  30   0   0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls

NWS TFX Office Area Forecast Discussion