Big Sky Resort

000
FXUS65 KTFX 060608
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1208 AM MDT Sun Sep 6 2026

Aviation Section Updated.

.KEY MESSAGES...

- Showers and thunderstorms tonight and Sunday, become a more
  widespread rainfall Sunday night into Monday.

- An isolated severe storm possible Sunday.

- Cool temperatures to begin the week, with some warmer afternoon
  temperatures for a few days mid week.

&&

.DISCUSSION...
/Issued 602 PM MDT Sat Sep 5 2026/ 

 - Meteorological Overview:
A slow moving upper level low will remain to our west through
Sunday, before slowly moving eastward Sunday night into Monday.
Expect waves of showers/thunderstorms to move through the CWA from
now through Sunday afternoon. There is the potential that a few
storms could become severe on Sunday, thus much of the CWA is in a
marginal risk for severe storms. As the upper level low moves
eastward Sunday night into Monday, the showers will change more
into a stratiform rain, with the heaviest rainfall expected over
North Central MT. There is also a marginal risk for excessive
rainfall that could cause flash flooding Sunday night into Mon
over North Central MT.

Drier and warmer conditions develop mid week, with afternoon
temperatures close to 10 degrees above normal by Thursday. By next
Friday, another upper level trof will start to move southward into
the Pacific Northwest, resulting in a moist southwesterly flow
over Montana. Thus the chances for precipitation will start to
increase once again next Fri/Sat.

 - Forecast Confidence & Scenarios:
The main concern on Sunday for any severe storms will be strong
wind gusts. This system on Sunday will not be as strong as the
weather system that went through the CWA on Wednesday, never the
less, an isolated severe storm is possible. Additionally, some
storms could also produce heavy rainfall. By Monday night, the
northern portions of North Central MT could have received between
1 and 3 inches of rainfall, with isolated amounts near 4 inches
possible. Overall, flooding is not expected, but in areas that
exceed 3 inches, the probability of minor flooding on small
streams and creaks starts to increase. Brusda

&&

.AVIATION...
06/06Z TAF Period 

North-Central and Central Montana: Low stratus will move in and
linger through most of the night with rain showers possible,
particularly along and west of the I-15 corridor. Generally
MVFR/IFR conditions are expected during this time but there is a
potential for temporary reductions into LIFR should fog/mist start
to develop. A larger concern will be the thunderstorm potential
tomorrow afternoon and evening with the chance for gusty winds and
gusty winds. Thunderstorms are expected to develop after 07/00Z,
starting in the south and quickly moving to the northeast.
Mountain obscuration will be a concern throughout the entire
period.

Southwest Montana: VFR conditions are expected to prevail over the
period with gusty south winds expected to develop in the Madison
River Valley Sunday afternoon. There is a low probability for some
fog developing at KBZN tonight but confidence was not high enough
to include it in the TAF.


For KGTF: MVFR conditions for lower ceilings develop by 06/08Z
with periods of IFR conditions possible between 06/10Z and 06/15Z.
Winds start to gradually pick up out of the north in the early
afternoon and become more northeasterly by 06/23Z. There is a
chance for scattered thunderstorms across the region Sunday
afternoon with a few expected to turn severe. For the KGTF
vicinity there are especially concerns for hail and gusty winds,
with the greatest chance for severe weather expected after 07/02Z.
The crosswind potential is low at this time but the greatest 
concerns would be related to the thunderstorm develop expected 
later in the day.   -thor

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  50  73  51  64 /  30  10  90 100 
CTB  46  63  46  58 /  90  80  80  90 
HLN  49  77  52  66 /  20  10  70  90 
BZN  46  82  49  70 /   0   0  60  70 
WYS  38  75  40  59 /   0   0  80  60 
DLN  43  80  46  66 /   0   0  70  70 
HVR  51  77  51  69 /  10  50  90 100 
LWT  49  79  50  70 /   0  20  90  90 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
&&

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