Dillon, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

218
FXUS65 KTFX 271353
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
753 AM MDT Sun Jul 27 2025

.KEY MESSAGES...

 - Shower and thunderstorm activity is expected each day through
   next weekend, primarily in the afternoon and evening periods.

 - Isolated strong to severe thunderstorms are possible across
   eastern portions of central and north-central Montana today and
   Monday.

 - The coverage and intensity of rainfall associated with daily
   showers and thunderstorms is expected to increase later this
   week.

&&

.UPDATE...

Morning update has been published, with the primary change being
to increase PoPs over the plains of Central and North Central
Montana to between a 15-20% chance through noon to account for
elevated convection that continues to lift to the northeast from
Western Montana and over the region. Additionally, PoPs during the
afternoon hours were increased across most locations so that
wording includes at least an isolated shower/thunderstorm mention.
Otherwise the remainder of the forecast remains on track, with
Hi-Res models continuing to depict another active day across the
Northern Rockies, with the opportunity for at least 1 or more
supercells during the afternoon and evening hours capable of
producing large hail and damaging wind gusts. These supercells
will be most favored over the plains and valleys of Central and
North Central Montana east of a Browning, to Great Falls, to
White Sulphur Springs line. - Moldan

&&

.DISCUSSION...
/Issued 502 AM MDT Sun Jul 27 2025/

 - Meteorological Overview:

Satellite imagery this morning shows some mid-level clouds and
moisture continuing to stream across central/N-central MT in SW
flow aloft as well as some lower clouds moving south along the
east slopes of the Rockies in Glacier county. Lower clouds are
occurring behind a boundary that moved south from AB with cooler
temps and elevated dewpoints, which should spread south as far as
around Great Falls by 6am. A subtle disturbance in the mid-level
SW flow may trigger a few light showers across portions of
N-central MT this morning as it ripples through.

By this afternoon thunderstorm development is expected again in a
similar fashion to yesterday, initially across SW MT with storms
tracking east and northeast across central and north-central MT
through this evening. Cloud coverage could temper instability
slightly across central/N-central MT, leading to somewhat lesser
coverage/intensity of thunderstorms vs yesterday, but sufficient
wind shear will still exist, thanks to a mid-upper level westerly
jet in place across southern AB/SK, and there is a marginal
(5-10%) risk of severe thunderstorms this afternoon across
primarily eastern portions of north-central MT.

The overall setup changes little on Monday, though a somewhat
better defined wave ejecting out of the west coast trough will
track across the Northern Rockies late Monday, bringing additional
lift. This, along with increased instability and shear will
support a more widespread marginal risk for severe thunderstorms
across much of central/north-central MT late Monday.

Tuesday through at least Friday, persistent southwesterly flow
aloft with elevated moisture and instability will continue the
pattern of daily afternoon shower and thunderstorm development.
Lower level southeasterly flow will import higher atmospheric
moisture content into the area. The increased moisture will result
in higher instability/buoyancy while wind shear decreases during
this period, supporting a risk for slower moving thunderstorms
with the more intense storms producing locally heavy rainfall.
Hoenisch

 - Forecast Confidence & Scenarios:

High resolution model ensembles focus the greatest coverage of
thunderstorms later today across central MT from southern Lewis
Clark county east through Fergus county. Damaging wind gusts
remain the primary threat with stronger thunderstorms again today,
though locally brief/heavy rainfall and small hail may accompany
some storms as well, particularly further north across north-
central MT. Hi-res guidance gives a 30-50% probability for gusts
in excess of 40 mph across central MT with a 5-15% risk of gusts
in excess of 55 mph primarily across Judith Basin and Fergus
counties. Hoenisch

&&

.AVIATION...
27/12Z TAF Period

Low clouds that slid south from AB into Glacier county and KCTB
early this morning should dissipate by 14z. VFR conditions prevail
otherwise across the area with scattered mid-high level clouds and
perhaps a few light/high-based showers across portions of N-central
MT this morning. Showers and thunderstorms develop again across
southwest MT this afternoon and track northeast across central/N-central
MT late late this afternoon and evening. Primary aviation concerns
will be lightning and strong/erratic wind gusts with a few stronger
cells producing brief heavier rain and local terrain obscuration.
Hoenisch

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  83  56  82  57 /  20  30  20  20
CTB  76  53  75  53 /  20  30  20  30
HLN  85  56  85  56 /  40  40  30  30
BZN  89  51  88  52 /  20  20  30  20
WYS  81  39  82  40 /   0   0  10   0
DLN  84  48  83  48 /  30  20  20  10
HVR  84  57  81  56 /  20  30  50  30
LWT  81  52  77  54 /  30  50  60  40

&&

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

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