Brady, Montana Weather Forecast Discussion

979
FXUS65 KTFX 291411
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
811 AM MDT Mon Sep 29 2025
.KEY MESSAGES...
- Hottest day of the week today, trending cooler thereafter.
- Shower and thunderstorm coverage increases today, mostly across
   Southwest Montana and along the Continental Divide.
- Opportunities for precipitation continue through the rest of
   the week, though no single timeframe appears to be a washout
   at this time.
&&
.UPDATE...
800 AM...Satellite imagery shows an area of primarily mid level
clouds lifting north across portions of central and southwest MT
this morning with radar indicating some potential for very light
rain showers/sprinkles. Have made some additional adjustments to
pops/sky through early this afternoon to account for this,
otherwise remainder of forecast is on track with well above
average temperatures expected across the area this afternoon.
Hoenisch
430 AM...updated forecast to add some light morning showers around
the Lewistown area. Brusda
&&
.DISCUSSION...
/Issued 429 AM MDT Mon Sep 29 2025/
- Meteorological Overview:
Upper level ridging ahead of a Pacific trough is beginning to shift
eastward, away from the region early this morning. As a result,
increasingly cyclonic southwest flow aloft is developing over the
region. A leading wave ejecting out of the main troughing setting up
just off the Pacific NW coastline today will result in scattered
showers and thunderstorms this afternoon into tonight, mostly across
Southwest Montana and along the Continental Divide. Inverted-V
forecast soundings for today suggest gusty winds will be a concern,
though the potential for any strong gusts appears low (And would be
highly localized if it were to happen) given overall lack of
instability. Showers look to continue into the overnight tonight,
mainly along the Continental Divide.
Additional rounds of showers and thunderstorms (Mainly in the late
afternoon and evening) look to develop through much of the rest of
the week as weak disturbances continue to eject from the Pacific NW
troughing. The risk for any stronger thunderstorms appears to
decrease through the week given the cooling trend for surface
temperatures.
Additionally, periods of breezy synoptic winds look to be around
at times this week, though at this point none of these spells of
winds look strong.
The core of the aforementioned Pacific NW troughing finally budges
late week, though at this time looks to split, sending most upper
level support southeastward toward UT and vicinity Friday into early
Saturday. Although this is the case, temperatures do look to trend
cooler still, with at least low-end opportunities for precipitation
hanging on Friday into Saturday.
Guidance is becoming a bit more consistent with another disturbance
shifting southeastward from the Gulf of Alaska toward the Northern
Rockies late Saturday into Sunday. Specifics such as overall
magnitude of the troughing, as well as how quickly it progresses are
still lower confidence, but this disturbance would at the very least
maintain precipitation chances through the weekend, with
temperatures remaining on the cooler side. -AM
- Forecast Confidence & Scenarios:
The main source of uncertainty in the forecast is associated with
the progression of troughing across the region late week into the
weekend. Both the track and strength of each of the two troughs
remains low confidence at this time. Given higher confidence in the
cooling trend, it seems valuable to note that there is at least a
20% chance for an inch of snow in the terrain this weekend. -AM
&&
.AVIATION...
29/12Z TAF Period.
A few showers could affect the Lewistown area before 15z, but no
impacts are expected. Otherwise, the main concern will be the
potential for showers/thunderstorms this afternoon and evening.
Some storms could produce gusty winds. Most of the storms will
affect SW MT during the afternoon hours and then along the front
range of the Rockies this evening and overnight. Brusda
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF  86  54  77  50 /  10  20  10  20
CTB  80  49  71  44 /   0  20  20   0
HLN  83  54  75  48 /  10  30  30  30
BZN  80  49  74  45 /  10  20  20  20
WYS  68  39  59  36 /  20  20  70  40
DLN  77  48  69  42 /  20  40  30  10
HVR  85  53  80  49 /   0  10   0  10
LWT  83  53  78  48 /  10  10  20  30
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls

NWS TFX Office Area Forecast Discussion