Helena, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

450
FXUS65 KTFX 080516
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1116 PM MDT Mon Jul 7 2025

Aviation Section Updated.

.KEY MESSAGES...

 - The warming trend continues for Tuesday and Wednesday, with a
   heat advisory in place for portions of North Central MT.

 - Showers and thunderstorms will return to Southwestern Montana
   Tuesday afternoon and to all areas on Wednesday and Thursday.

 - There will be a brief cooldown on Thursday and Friday before it
   warms back up for the weekend.

&&

.UPDATE...
/Issued 828 PM MDT Mon Jul 7 2025/
Updated forecast for tonight is out. No changes, other than to
freshen the grids. Other than passing clouds tonight, it will be
quiet.

On Tuesday, expect warmer afternoon temperatures, with a heat
advisory beginning for portions of North Central MT. There will be
the chance for a late afternoon thunderstorm over Southwest MT,
mostly south of I-90 from Butte to Bozeman. The main impact will
be lightning and strong wind gusts. On Wednesday, similar
conditions are expected, but the thunderstorms will be a bit more
widespread and also spread further north into North Central MT.
Again, some storms could produce strong wind gusts. Brusda

&&

.DISCUSSION...
/Issued 828 PM MDT Mon Jul 7 2025/

 - Meteorological Overview:

An upper-level ridge is building in over North-central, Central, and
Southwestern Montana this afternoon. This upper-level ridge will
remain over North-central, Central, and Southwestern Montana through
Wednesday evening. This will bring dry weather to the area this
afternoon through Wednesday morning outside of a few isolated
thunderstorms in Southwestern and Central Montana Tuesday afternoon
and evening. It will also bring hot temperatures to all of the lower-
elevations of North-central, Central, and Southwestern Montana on
Tuesday and Wednesday. For most lower-elevation locations these will
be the hottest temperatures of the year so far. On Wednesday due to
a strong surface pressure gradient and approaching surface cold
front it will be windy with the strongest winds along the Rocky
Mountain Front and adjacent plains.

Wednesday afternoon/evening an upper-level trough associated with a
surface cold front will begin to move over North-central, Central,
and Southwestern Montana. This will bring showers and thunderstorms
to the area Wednesday afternoon and evening. On Thursday the upper-
level trough remains over North-central, Central, and Southwestern
Montana. This will cool down temperatures to below seasonal averages
and due to southwest flow aloft bring showers and thunderstorms to
the area Thursday afternoon and evening. On Friday an upper-level
ridge builds in over North-central, Central, and Southwestern
Montana. This will dry out the area and allow temperatures to warm
up. On Saturday and Sunday there will be northwest flow aloft over
North-central, Central, and Southwestern Montana which will allow
temperatures to warm to above seasonal averages each day with mostly
dry conditions.

 - Forecast Confidence & Scenarios:

On Tuesday there is a 10 - 30% chance for high temperatures of 100
degrees or greater along the Milk River and Missouri River Valley in
North-central Montana. On Wednesday there is a 40 - 60% chance for
high temperatures of 100 degrees or greater along the Milk River and
Missouri River Valley in North-central Montana. Across much of North-
central Montana east of I-15 there is greater than a 60% chance for
high temperatures greater than 95 degrees on Tuesday and Wednesday.
Across much of North-central Montana east of I-15 there is greater
than a 60% chance for low temperatures greater than 60 degrees on
Wednesday morning. Across much of North-central Montana east of I-15
there is a 20 - 40% chance for low temperatures greater than 64
degrees on Wednesday morning. As a result a Heat Advisory was issued
for the lower elevations of Cascade County, Choteau County, Hill
County, and Northern Blaine County from Tuesday afternoon through
Wednesday evening.

On Tuesday there is a 15 - 20% chance for thunderstorms in
Southwestern and Central Montana. On Wednesday there is a 15 - 20%
chance for thunderstorms across North-central Montana and a 30 - 40%
chance for thunderstorms across Central and Southwestern Montana. On
Thursday there is a 30 - 60% chance for thunderstorms across North-
central, Central, and Southwestern Montana. On Wednesday there is a
60 - 90% chance for wind gusts of 45 mph or greater along the Rocky
Mountain Front and adjacent plains. Elsewhere across much of North-
central, Central, and Southwestern Montana there is a 20 - 50%
chance for wind gusts of 35 mph or greater. -IG

&&

.AVIATION...
08/06Z TAF Period

VFR conditions are expected throughout the duration of the
0806/0906 TAF period as upper level ridging builds in over the
Northern Rockies; however, showers and thunderstorms developing
across Southwest Montana between 18-21z Tuesday and persisting
through 04-07z Wednesday will be capable of producing gusty and
erratic winds at the KBZN and KWYS terminals. These high based
showers and storms are not expected to reduce CIGS or VIS below
VFR. Scattered mountain obscuration is possible Tuesday afternoon
and evening across Southwest and into portions of Central Montana
due to the aforementioned showers and storms. - Moldan

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  85  57  95  61 /  10   0   0   0
CTB  82  51  89  58 /  10   0   0   0
HLN  87  57  96  60 /   0   0   0   0
BZN  87  53  95  55 /   0   0   0  10
WYS  79  40  84  41 /   0   0  10  20
DLN  85  51  90  52 /   0   0   0  20
HVR  83  56  98  61 /  10   0   0   0
LWT  79  54  90  59 /  10   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM Tuesday to 8 PM MDT Wednesday for
Cascade County below 5000ft-Hill County-Northern Blaine County-
Western and Central Chouteau County.

&&

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