Lewistown, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

020
FXUS65 KTFX 202110
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
310 PM MDT Sun Jul 20 2025

.KEY MESSAGES...

 - There is a marginal to slight risk for severe weather Monday
   afternoon across portions of central Montana.

 - Scattered showers and thunderstorms expected across central and
   north-central Montana Monday through Wednesday.

 - Warmer and drier conditions expected by the end of the work
   week.

&&

.DISCUSSION...

 - Meteorological Overview:

Isolated showers and thunderstorms will continue across the region
through the rest of the evening. For the most part these storms
will remain sub-severe, however, an isolated severe wind gust or
1-inch hail cannot be ruled out.

The upper level trough will reach Montana by Monday afternoon with
showers and thunderstorms becoming more widespread as the day
progresses. Afternoon thunderstorms may turn severe across
portions of central and north-central Montana, particularly around
Fergus county with the main threat being strong wind gusts and
large hail.

The trough will slowly make its way across the region through
Wednesday allowing for a period cooler and wetter conditions. In
the wake of the trough, transient ridging moves across the state
allowing for warmer temperatures to return through the weekend.
Conditions across the region will generally remain dry, however,
there is a chance for some isolated afternoon thunderstorm
activity particularly across southwest Montana.


 - Forecast Confidence & Scenarios:

Severe Weather Threat Monday:

There is a marginal risk for severe weather that encompasses much
of central and north-central Montana with a slight risk focused on
Fergus county. As of now, these regions aptly describe the
confidence in stronger thunderstorms. The main concern will be
discrete thunderstorms developing around the Judith Basin/Meagher
county area and tracking to the east into a more favorable
environment towards Fergus county. The impacts with any storm
that develops tomorrow will be strong winds and large hail. There
is a slight bit of hesitancy given that some of the other hi-res
models are not as aggressive as placing storms in the region
compared to others. But there is enough of a probability given the
decent forcing, moisture, and instability of the environment to
warrant some concerns for Monday afternoon.


Rainfall Monday-Wednesday:

Precipitation amounts have gone down across much of the region
with the exception of locations east of a line between Havre and
Stanford. The latest NBM probabilities have moved higher amounts
to the east but have still maintained a broad 40-60% chance of
most of central and north-central Montana receiving at least 0.25"
-thor


&&

.AVIATION...
20/18Z TAF Period.

VFR conditions will prevail through 06z Monday, with CIGS lowering
to MVFR at the KCTB and KGTF terminals through 15z Monday in wake
of a southward advancing cold front. Isolated to widely scattered
showers and thunderstorms will develop this afternoon across
portions of Southwest and Central Montana, generally along and
southeast of a KHLN to KLWT line. These showers and storms are not
expected to reduce CIGS or VIS below VFR, but mountain top
obscuration and erratic winds are possible at or near the KLWT,
KBZN, and KEKS terminals. - Moldan

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  57  72  56  73 /  10  50  70  50
CTB  52  59  50  64 /  30  80  80  70
HLN  57  79  55  76 /  20  60  60  50
BZN  51  90  52  82 /  20  50  40  60
WYS  43  81  45  77 /  20  30  20  30
DLN  49  85  49  78 /  10  40  20  40
HVR  56  77  54  72 /  20  40  80  60
LWT  52  76  51  71 /  30  50  90  70

&&

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

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