789
FXUS65 KTFX 071455
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
855 AM MDT Mon Sep 7 2026

.KEY MESSAGES...

 - Moderate to heavy rain will continue to affect mainly North
   Central Montana through Tuesday morning.

 - Warmer and drier conditions arrive for Wednesday and Thursday.

 - Another cooler wetter period is expected for Friday and into
   the weekend.

&&

.UPDATE...
Updated forecast is out for this morning, with pops mostly
freshened for the rest of this morning. A band of rain continues
to push northward this morning through North Central MT. Rainfall
around a half inch is common with this band. Other isolated
thunderstorms are developing west of Bozeman currently. The focus
for rain/thunderstorms will shift to the Highway 2 corridor from
Browning to Harlem this afternoon. Brusda

&&

.DISCUSSION...
/Issued 200 AM MDT Mon Sep 7 2026/

 - Meteorological Overview:

Deep and slow moving upper level low pressure will continue to
slowly drift eastward over the Treasure State over the next 36-48
hours, bringing a prolonged period of cool and wet weather.
Overnight showers and thunderstorms that moved through the area
will gradually coalesce across North Central Montana and along the
Rocky Mountain Front, where they will more or less persist
through the day today and into early Tuesday.

A brief period of respite from the wet weather will arrive
Wednesday and Thursday as weak upper level ridging transits the
area. As the ridge moves overhead, temperatures will be a bit
closer to average, with highs generally in the 70s to low 80s
across the lower elevations. This warmer and drier period will not
last long, however, as our next upper level low will push in
Friday and Saturday, bringing another prolonged period of cooler
and wetter weather.

 - Forecast Confidence & Scenarios:

Rain through Tuesday: Models remain in overall good agreement
that the heaviest rainfall will generally remain confined to the
Rocky Mountain Front and along the Hi-Line, where amounts of 1.5
to 3 inches of additional rainfall remain possible. Areas that
received heavy rainfall from the strong to severe thunderstorms
that rolled through the area Sunday night will need to be watched
extra closely, as this extra moisture may provide the antecedent
conditions needed for the rainfall to over saturate some of the
soils locally and result in some localized flooding. Ludwig

&&

.AVIATION...
07/12Z TAF Period

RA with embedded TSRA will continue to bring a mix of IFR to MVFR
conditions across North Central Montana airports (KCTB, KHVR,
KGTF, KLWT) through the daylight hours today due to a mix of lower
visibility and ceilings. Further south, watch for SHRA with
embedded TSRA to continue through at least the morning hours
before some clearing arrives late this morning/after 18z. RA will
persist across the plains beyond 12z tomorrow across the plains
before conditions improve there as well.

For KGTF: Expect generally MVFR conditions through the day today
with periods of IFR conditions through the day during heavier rain
and thunderstorms. Winds will be on the increase today, and while
winds through 19z or so will be aligned enough with the runway to
keep crosswinds under 15 kts, a shift further to the west is
expected by 21z as winds increase further, resulting in a near
certainty of crosswinds approaching 20 to 25kts. Ludwig

&&

.HYDROLOGY...

While areas along the Rocky Mountain Front have received 0.75" to
1.5" of rainfall over the past day or two, there hasn`t been much
of a response in creeks/streams yet due to the drier grounding
soaking all the rain up. The main concern is another additional
widespread 1 to 3 inches and isolated 4 inches through Tuesday
morning on a more saturated ground. Areas that get the higher end
3 to 4 inch totals may see minor overflow in creeks/streams along
with muddied rural roads. The wet conditions can also cause
rock/debris slides in the higher terrain. Therefore, a flood watch
was issued through Tuesday. Farther east across North-Central MT
will see wetting rain, but confidence for those higher end totals
remain low. Two things to watch for is any eastern shift of these
amounts farther east along US Highway 2 towards Hill County, and
any heavier showers that affect areas that saw heavy rain Sunday
night could see some increased risk for minor flooding.
-Wilson/Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  63  46  64  43 / 100  40  70  10
CTB  56  43  60  43 / 100  90  90  10
HLN  65  43  68  44 / 100  20  10   0
BZN  67  39  70  39 /  90   0   0   0
WYS  60  30  63  30 /  30   0   0   0
DLN  66  36  70  37 /  40   0   0   0
HVR  67  46  63  43 / 100  90 100  50
LWT  67  43  64  41 /  90  20  30  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday morning for East Glacier Park Region-
Eastern Glacier, Western Toole, and Central Pondera-Eastern
Pondera and Eastern Teton-Eastern Toole and Liberty-Northern
High Plains-Southern High Plains-Southern Rocky Mountain Front.

&&

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