063
FXUS65 KTFX 011709
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1109 AM MDT Mon Sep 1 2025

Aviation Section Updated.

.KEY MESSAGES...

- An isolated shower or thunderstorm over North Central MT today
  and Tuesday, otherwise dry and very warm.

- A slow cooling trend towards normal afternoon September
  temperatures expected late this week.

- Showers and thunderstorms develop mostly over Southwest MT this
  weekend.

&&

.UPDATE...
/Issued 830 AM MDT Mon Sep 1 2025/

Today it will be another hot and mostly dry day across North-
central, Central, and Southwestern Montana. This afternoon and
evening there will be isolated showers along the Rocky Mountain
Front. For the update Pops along the Rocky Mountain Front were
increased to reflect the latest hi-res model guidance. The rest
of the forecast is on track. -IG

&&

.DISCUSSION...
/Issued 830 AM MDT Mon Sep 1 2025/

 - Meteorological Overview:
An upper level ridge of high pressure will be reside over the
Pacific Northwest for much of this week. This ridge will slowly
shift east/west a bit each day. The further east the ridge is,
like today/Tue...the warmer the afternoon temperatures will be.
The further west the ridge shifts...Thu/Fri...the slightly cooler
temperatures. Additionally, the airmass will be unstable enough,
that an isolated shower/thunderstorm will be possible today,
mostly over the Northern Rockies, including the Glacier Park area.
On Tuesday, a weak boundary will move southward from Canada,
mainly affecting areas east of Havre. Thus any precipitation on
Tue should be limited to just the Harlem/Turner areas. Generally
dry conditions...along with a slow/minor fall in afternoon
temperatures is expected for the 2nd half of the work week.

For Sat/Sun...the flow aloft will try to switch to more of
southwesterly flow, per the GFS model. This will allow for mostly
afternoon and evening showers/thunderstorms to develop over
Southwest MT.

 - Forecast Confidence & Scenarios:
The main weather impacts will be smoke over the next few days, in
terms of how dense does it get. For now impacts are expected to be
mainly limited to aviation and air quality.

Secondly thunderstorm potential this weekend over Southwest MT,
with the potential for some storms producing some heavier
rainfall. Overall, confidence is low at this time for any storms
producing heavy rainfall. Brusda

&&

.AVIATION...
01/18Z TAF Period.

VFR conditions are expected to prevail at area terminals through
the period.

Some minor impacts are possible though, with the potential for a
few mountain showers/thunderstorms along the divide starting after
22z today. Also, areas of smoke will reduce visibility at times.
Some of the smoke will move southward from Canada into North
Central MT on Tuesday morning.

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  89  56  88  54 /   0  10   0   0
CTB  86  52  83  51 /  10  10   0   0
HLN  89  57  89  56 /   0   0   0   0
BZN  89  52  89  51 /   0   0   0   0
WYS  79  39  81  40 /   0   0   0   0
DLN  84  50  86  48 /   0   0   0   0
HVR  87  56  83  50 /   0  10   0   0
LWT  85  55  85  51 /   0   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

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