320
FXUS65 KTFX 041440
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
840 AM MDT Wed Jun 4 2025

.KEY MESSAGES...

 - There will be chances for showers and thunderstorms today
   through Saturday with the highest chances and most widespread
   rainfall today.

 - It will gradually warm up Today through Monday.


&&

.UPDATE...

Satellite imagery this morning shows some mid level clouds exiting
the forecast area to the east and entering from the NW with
little clouds, but some patchy/thin layers of wildfire smoke in
between across the majority of north-central and southwest MT.
Another day beneath cyclonic NW flow aloft around a larger upper
level level trough centered near Hudson bay will bring scatted
showers and isolated thunderstorm development by this afternoon.
Generally weak instability will limit the coverage and strength of
any thunderstorms but relatively light steering flow will allow
cells to produce localized wetting precipitation with perhaps some
small hail in cells that can maintain an updraft for long enough.
Greatest coverage of showers will be across the central MT
mountains with some showers lingering into this evening before
dissipating. Hoenisch

&&

.DISCUSSION...
/Issued 431 AM MDT Wed Jun 4 2025/

 - Meteorological Overview:

Today through Saturday there will be a series of upper-level
shortwave troughs that will move through with northwest flow aloft
over North-central, Central, and Southwestern Montana. This will
bring showers and thunderstorms to the area Today through Saturday.
Today showers and thunderstorms will be primarily confined to
locations north of the I-90 corridor of North-central, Central, and
Southwestern Montana. This morning if skies clear enough portions of
North-central Montana have the potential for patchy fog to form. See
the Forecast Confidence & Scenarios section for details. Showers and
thunderstorms will be the most widespread today compared to the rest
of the week through Saturday. Temperatures will gradually warm up
today through Saturday.

On Sunday an upper-level ridge builds in over North-central,
Central, and Southwestern Montana. This will warm temperatures up
further to well-above seasonal averages with mostly dry weather.
The upper-level ridge will remain over North-central, Central, and
Southwestern Montana on Monday. This will allow temperatures to
warm up further with dry conditions. Monday night/early Tuesday
morning the upper-level ridge will begin to flatten. This will
bring cooler temperatures and widespread showers and thunderstorms
back to North-central, Central, and Southwestern Montana.

 - Forecast Confidence & Scenarios:

For fog there is a 10 - 30% chance for patchy fog to form across
portions of the lower-elevations of North-central Montana. Today
there is a 10 - 30% chance for a tenth of an inch of rain or
greater across North-central and Central Montana. However due to
this being a northwest flow event which models don`t handle very
well those probabilities are too low. Today there is a 15 - 35%
chance for thunderstorms across North-central, Central, and
Southwestern Montana north of the I-90 Corridor. On Thursday
across North- central, Central, and Southwestern Montana there is
a 15 - 40% chance for thunderstorms. On Friday there is a 5 - 15%
chance for thunderstorms across North-central, Central, and
Southwestern Montana. On Monday there is a 30 - 50% chance for
high temperatures of 90 degrees or greater across North-central
Montana. -IG

&&

.AVIATION...
04/12Z TAF Period

VFR conditions will prevail beneath northwest flow aloft;
however, another round of showers and isolated thunderstorms will
develop between 15z this morning and 03z Thursday, mainly
northwest of a line from KHLN to KBZN. Main impact from any
shower that impacts or is within the vicinity of a given terminal
will be a brief period of gusty and erratic winds. Otherwise, the
only other concern to terminal operations during the 0412/0512
TAF period will be the potential for fog developing at/near the
KCTB, KHVR, KGTF, and KWYS terminals prior to 15z this morning.
Mountain obscuration will increase this afternoon for peaks above
9kft. - Moldan

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  67  41  73  47 /  20  20  10   0
CTB  65  39  73  45 /  30  20   0   0
HLN  69  45  75  48 /  20  20  10   0
BZN  66  38  70  42 /  10  20  20   0
WYS  62  29  65  30 /   0  10  30  10
DLN  63  37  69  41 /  10  10  10   0
HVR  70  43  76  47 /  30  30  10   0
LWT  62  40  67  44 /  40  50  30   0

&&

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

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