216
FXUS65 KTFX 070944
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
344 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.

&&

.DISCUSSION...

 - 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...
07/00Z TAF Period

Main concern this afternoon is strong thunderstorms moving across
the region from the Southwest to the Northeast with some being
severe and capable of producing large hail and wind gusts of 50
KT. These storms will primarily impact KGTF, KHLN, and KLWT
however KHVR could be impacted if convection persists into the
night. MVFR conditions for Northern and Central MT will continue
with chances for IFR overnight as the storm mode transitions to a
more widespread moderate to heavy rain system.


For KGTF: Severe thunderstorm potential will be from 01z to 02z
this evening. The primary hazards expected will be strong gusts
and a potential for large hail. MVFR ceilings will return
overnight into tomorrow morning along with restrictions to
visibility due to moderate rain and mist until late tomorrow
morning. - Akins

&&

.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