Helena Valley Northwest, MT 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

123
FXUS65 KTFX 051721
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1121 AM MDT Sun Apr 5 2026

Aviation Section Updated.

.KEY MESSAGES...

- Southwest Montana remains mild for the next couple of days
  while cloudier and cooler conditions prevail over the plains.

- A fast moving cold front will bring a period of more
  widespread strong winds on Tuesday.

- Light mountain snow and lower elevation rain and snow
  showers develop Tuesday night into Wednesday.

- Another trough looks to move in during the second half of next
  weekend for another cool down and increased shower activity.

&&

.UPDATE...
/Issued 802 AM MDT Sun Apr 5 2026/

Northwest flow aloft, with a weak embedded wave moving southeast
and over North Central Montana, will reside over the Northern
Rockies through this Easter Sunday. At the surface a "cooler"
airmass has settled into place across the plains of Central and
North Central Montana thanks to the passage of a cold front on
Saturday, with this front now stalled along a Rogers Pass, to
Monarch, to Judith Gap line. High temperatures north of this
stalled front will largely range from the low 40s to low 50s today,
with the upper 50s to low 60s for points south across the valleys
of Central and Southwest Montana. While most areas will remain
dry through the day today a few rogue rain/snow showers can`t be
ruled out along the Hi-Line, mainly east of Cut Bank and north of
the US Hwy 2 corridor. The on-going forecast remains on track and
minimal updates were made. - Moldan

&&

.DISCUSSION...
/Issued 802 AM MDT Sun Apr 5 2026/

 - Meteorological Overview:

Northwesterly flow aloft will remain over the Northern Rockies
for the next day or so while a 1040 mb surface high moves
southeastward out of Canadian prairies into northern plains. This
will bring a moist easterly flow in the low levels for cloudier
and cooler conditions, particularly for central and north-central
MT. There may be some patchy fog and spotty light precipitation,
though easterly breezes should reduce fog impacts some and
precipitation amounts look to be negligible and mostly
concentrated along the Hi-Line.

On Tuesday, a compact Pacific trough and attendant cold front
will bring a period of strong gusty winds to much of the forecast
area. An H700/H500 60 to 80 kt jet, supported by cold air
advection, looks to pass through during late morning and afternoon
hours when diurnal mixing is near its peak. There will also be
mountain wave activity that will contribute to localized stronger
gusts near areas of higher terrain. These factors will make this
winds more impactful than a typical event. The most persistent
strong winds look to occur along the Rocky Mountain Front and the
plains along and west of the I15 corridor where max gusts in the
75 to 90 mph range will be common. Most of the winds will occur in
the daylight hours with the exception of Fergus County and areas
near the Bear`s Paw Mountains. These locations will see their
strongest winds later in the afternoon and continuing well into
the overnight hours.

Light mountain snow and lower elevation scattered rain and snow
shower activity will develop on the backside of this system with a
short period of below average temperatures following the cold
frontal passage. Milder conditions move in for next weekend before
another trough passes through heading into early next week. While
this system should bring some cooler temperatures and increased
shower activity, confidence is low in regards to precipitation
coverage and amounts due to a large portion of the said trough
shearing off and moving southeast toward the Great Basin and
southwestern conus. - RCG

 - Forecast Confidence & Scenarios:

Strong winds on Tuesday...

Confidence continues to increase for a compact mid- level low to
bring a period of strong winds during the day on Tuesday. Any
shifts in timing of the low level jet would result in the
strongest winds being more localized. While there certainly have
been faster jetstreams than the 60 to 70 kts this time around, a
mid- day or afternoon passage greatly increases momentum transfer
from higher levels compared to an overnight or early morning
passage. Currently, the highest confidence for higher end 70 to 90
mph wind gusts are mostly along the Rocky Mountain Front and the
plains west of I90. Winds decrease some and become more sporadic
heading east and southeast.

Impacts will include difficult to dangerous travel conditions for
high profile or light weight vehicles, localized visibility
reductions from blowing dust, and instances of infrastructure/tree
damage. Additionally, a brief period of elevated fire weather
conditions may develop for central/southwestern areas roughly
south of the US highway 12 corridor. The high wind watch was
expanded to include much of central/north-central MT and portions
of the southwest. I did leave out the Helena and Bozeman areas for
now due to low confidence in criteria gusts lasting more than an
hour or two. Most of the watches start Tuesday morning and in the
evening. The only exception to this is for Fergus County and the
Berar`s Paw zones. These areas will see their peak winds starting
later in the afternoon and persisting into the overnight hours.
Wednesday may even be windy for these eastern areas, but held off
extending the high wind watch beyond early Wednesday morning.
- RCG

&&

.AVIATION...
05/18Z TAF Period

VFR conditions will prevail at the KBZN, KEKS, and KHLN terminals
during this TAF Period with light and variable winds and high-level
clouds around. At the rest of the terminals there will be MVFR level
ceilings around after 06/00Z. The low ceilings will affect the KCTB
terminal first before moving to the KHVR, KGTF, and KLWT terminals
towards the end of this TAF Period. At the KHVR terminal there is a
15 - 25% chance for rain from now through 06/00Z. There will be
periods of mountain obscuration after 06/00Z across North-central
Montana. Monday morning there is a low chance for patchy fog at the
KHLN and KBZN terminals. -IG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  51  29  56  40 /  10  10  10  10
CTB  45  27  53  37 /  20  10  10   0
HLN  59  35  62  38 /   0   0  10   0
BZN  62  32  61  34 /   0   0  10  10
WYS  55  25  57  25 /   0   0  10  10
DLN  63  35  64  37 /   0   0   0   0
HVR  45  27  51  32 /  30  10   0  10
LWT  51  28  48  34 /  10  10  10   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Tuesday morning through Tuesday evening for
East Glacier Park Region-Eastern Glacier, Western Toole, and
Central Pondera-Northern High Plains-Southern High Plains-
Southern Rocky Mountain Front.

High Wind Watch from Tuesday morning through Tuesday evening for
Beaverhead and Western Madison below 6000ft-Big Belt, Bridger
and Castle Mountains-Cascade County below 5000ft-Eastern Pondera
and Eastern Teton-Eastern Toole and Liberty-Judith Basin County
and Judith Gap-Little Belt and Highwood Mountains-Madison River
Valley-Northwest Beaverhead County-Upper Blackfoot and MacDonald
Pass-Western and Central Chouteau County.

High Wind Watch from Tuesday afternoon through late Tuesday
night for Bears Paw Mountains and Southern Blaine-Fergus County
below 4500ft-Snowy and Judith Mountains.

&&

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