Lewistown, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

865
FXUS65 KTFX 192056
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
256 PM MDT Thu Mar 19 2026

.KEY MESSAGES...

 - Strong gusty winds weaken this evening, but pick back up again
   Friday morning.
 - A cold front slides through the Treasure State Friday, bringing
   temperatures closer to normal.
 - Warm and breezy conditions continue into next week.

&&

.DISCUSSION...

 - Meteorological Overview:

An anomalously strong ridge of high pressure will remain
entrenched over the Great Basin and southwestern CONUS through the
first half of the weekend. The Northern Rockies will be situated
on the northern periphery of this feature, which will continue to
bring dry and unseasonably warm conditions while strong westerly
flow aloft maintains periods of windy conditions, scattered to
broken mid- and higher level cloudiness, and even a few isolated
showers through Saturday.

A stronger 60 to 80 kt H700 jet still looks to cross the Northern
Rockies Friday through early Saturday in advance of an
approaching Pacific trough/cold front and bring an opportunity for
more widespread stronger winds. The focus will initially be along
the Rocky Mountain Front/adjoining plains and over and near the
central MT island ranges. By Saturday portions of southwest
Montana will begin to see stronger winds with 50 kt H700 flow
coming in from the southwest in addition to scattered shower
activity helping transfer some of these stronger winds to the
surface. Winds decrease in a northwest to southeast fashion by
Saturday evening.

Ridging aloft looks to build in briefly early next week before
another Pacific trough and cold front moves through Wednesday into
Thursday. It`s kind of early to start interrogating some of
specifics with this system, but the ensembles are hinting at
stronger end H700/H500 flow on the order of 70 to 100 kts. Should
this occur, then we may be looking at another higher end wind
event depending on diurnal timing and other factors. - RCG

 - Forecast Confidence & Scenarios:

Windy conditions continue through Saturday...

Friday through Saturday, stronger winds aloft associated with the
Pacific trough and cold front look to sweep through the Northern
Rockies. The uncertainty that impacts the magnitude of winds for
northern areas will be how fast a Canadian front moves south and
undercuts the elevated winds aloft. The GFS suite typically
handles these scenarios a little better than other ensembles and
times the front to move southward into the plains sometime
Saturday morning or early afternoon. This suggests the opportunity
for stronger winds along the Rocky Mountain Front and the plains
will roughly run from Friday morning through early Saturday before
shifting the focus southward into southwest MT. NBM probabilities
for 60 mph wind gusts on Friday and Saturday continue to be less
than ideal for high wind products, but it still shapes the normal
problem areas with a rough 30 to 60% chance, including the Rocky
Mountain Front, plains west of of I15, central MT 87/200 corridor,
and the narrow south to north oriented valleys of southwest MT.
Given the meteorological set up, I went ahead and put a watch out
for the higher confidence locations with anticipation of better
model agreement prior to upgrading to warnings. - RCG

&&

.AVIATION...
19/18Z TAF Period

VFR conditions will prevail over the next 24 hours, though strong
gusty winds will continue, especially along the Rocky Mountain
Front through the next 24 hours. Watch for occasional gusts over
50 kts at KCTB, though a rogue 50+kt gust at KGTF can`t be ruled
out. Mountain wave turbulence will be present through the
forecast period as well. Ludwig

&&

.FIRE WEATHER...

Warm, breezy, and dry conditions are expected through the end of the
work week as we remain under the northern edge of an upper level
ridge. While this will result in elevated fire weather conditions,
RH values outside of the southwest MT valleys should mostly remain
above 20%, and recent snowfall and snowmelt should keep fine fuels
and soils moist enough to prevent conditions from becoming
critical across the plains. The southwestern valleys, however,
will be much drier and will have the greatest risk for increased
fire growth and spread. - RCG/Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  51  75  49  63 /   0   0   0  30
CTB  45  67  44  53 /  10  10  10  30
HLN  43  74  44  63 /   0   0   0  40
BZN  42  78  45  71 /   0   0   0  20
WYS  27  64  29  62 /   0   0   0  20
DLN  42  76  44  71 /   0   0   0  10
HVR  45  74  47  59 /   0  20   0  30
LWT  46  74  45  60 /   0   0   0  50

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until midnight MDT tonight for East Glacier
Park Region-Eastern Glacier, Western Toole, and Central Pondera-
Northern High Plains-Southern High Plains.

High Wind Warning from 6 AM Friday to noon MDT Saturday for East
Glacier Park Region-Eastern Glacier, Western Toole, and Central
Pondera-Northern High Plains-Southern High Plains-Southern Rocky
Mountain Front-Upper Blackfoot and MacDonald Pass.

High Wind Warning from 9 AM Friday to noon MDT Saturday for Big
Belt, Bridger and Castle Mountains-Cascade County below 5000ft-
Fergus County below 4500ft-Judith Basin County and Judith Gap-
Little Belt and Highwood Mountains.

&&

$$
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