Helena, Montana 7 Day Weather Forecast
Wx Forecast - Wx Discussion - Wx Aviation
|
NWS Forecast for Helena MT
National Weather Service Forecast for:
Helena MT
Issued by: National Weather Service Great Falls, MT |
Updated: 10:32 am MDT Jul 12, 2025 |
|
This Afternoon
 Mostly Sunny
|
Tonight
 Mostly Clear
|
Sunday
 Sunny
|
Sunday Night
 Mostly Clear
|
Monday
 Sunny
|
Monday Night
 Chance T-storms then Chance Showers
|
Tuesday
 Chance Showers then Showers Likely
|
Tuesday Night
 Chance T-storms
|
Wednesday
 Chance Showers
|
Hi 90 °F |
Lo 60 °F |
Hi 94 °F |
Lo 62 °F |
Hi 92 °F |
Lo 56 °F |
Hi 69 °F |
Lo 50 °F |
Hi 66 °F |
|
This Afternoon
|
Mostly sunny, with a high near 90. West wind 10 to 13 mph, with gusts as high as 25 mph. |
Tonight
|
Mostly clear, with a low around 60. West southwest wind 6 to 13 mph, with gusts as high as 24 mph. |
Sunday
|
Sunny, with a high near 94. Light and variable wind becoming northwest 5 to 9 mph in the afternoon. Winds could gust as high as 20 mph. |
Sunday Night
|
Mostly clear, with a low around 62. West wind 6 to 10 mph, with gusts as high as 20 mph. |
Monday
|
Sunny, with a high near 92. Light west southwest wind becoming west northwest 8 to 13 mph in the morning. Winds could gust as high as 25 mph. |
Monday Night
|
A chance of showers and thunderstorms. Mostly cloudy, with a low around 56. North wind 10 to 14 mph, with gusts as high as 26 mph. Chance of precipitation is 40%. |
Tuesday
|
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after noon. Mostly cloudy, with a high near 69. North wind 8 to 14 mph, with gusts as high as 26 mph. Chance of precipitation is 60%. |
Tuesday Night
|
A chance of showers and thunderstorms, mainly before midnight. Mostly cloudy, with a low around 50. North northwest wind 6 to 14 mph, with gusts as high as 25 mph. |
Wednesday
|
A slight chance of showers, then a chance of showers and thunderstorms after noon. Partly sunny, with a high near 66. |
Wednesday Night
|
Partly cloudy, with a low around 48. |
Thursday
|
Sunny, with a high near 78. |
Thursday Night
|
Mostly clear, with a low around 51. |
Friday
|
Sunny, with a high near 86. |
Forecast from NOAA-NWS
for Helena MT.
|
Weather Forecast Discussion
715
FXUS65 KTFX 121643
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
1043 AM MDT Sat Jul 12 2025
Forecast and Aviation Section Updated.
.KEY MESSAGES...
- Hot and generally dry conditions expected through the weekend.
- Chance for isolated thunderstorms along the Hi-Line Sunday
evening.
- Cooler and wetter conditions return Monday through Wednesday.
&&
.UPDATE...
Current forecast is on track, no changes planned for this morning.
&&
.DISCUSSION...
/Issued 450 AM MDT Sat Jul 12 2025/
- Meteorological Overview:
Northwest flow will continue through today and tomorrow with
temperatures warming into the upper 80s to mid 90s across the lower
elevations of north-central, central, and southwest Montana.
Generally dry conditions are expected through the weekend outside
of a 20-30% chance for isolated thunderstorms across the Hi-Line
Sunday afternoon/evening.
A strong cold front pushes through Monday into Tuesday bringing
temperatures across north-central and central Montana down 10 to
15 degrees. There is a chance for widespread rain across much of
north-central and central Montana with more isolated amounts down
into southwest Montana through Wednesday. In the wake of the
trough, temperatures will start to moderate with some warming
expected by the weekend.
- Forecast Confidence & Scenarios:
Hi-Line Thunderstorms on Sunday:
There are early indications from the RDPS and NAM 3km that there
could be some thunderstorms along the Canadian border Sunday
afternoon/evening with just enough CAPE and shear to cause
problems. In lieu of more hi-res guidance, which does not quite
go out far enough at this time, the most likely scenario is that
most of the thunderstorm activity will stay north of the Canadian
border. However, a few cells may turn south into Montana causing
concern as those tend to be on the stronger side. The main
concerns with any thunderstorm that develops would be strong
winds and hail.
Storm System Monday-Wednesday:
Despite the start of this event only being a couple days out,
there are still some drastic differences in how the models are
handling both the timing and position of the upper level trough
that is expected to move through the region.
To give an idea on the current timing differences, the ECMWF has
the trough axis over western Montana at 00Z Wednesday, the GDPS
has this occurring at 06Z Wednesday, and the GFS has the trough
axis reaching western Montana by 15Z Wednesday. To further add
complications, the 06Z run of the NAM is suggesting the trough
axis reaches western Montana by 09Z Tuesday, 12-24 hours ahead of
the long-range models. Not to mention that while the ECMWF, GDPS,
and NAM agree on the trough digging through much of the state,
which would give us more moisture and higher rainfall amounts, the
GFS flattens out the trough and keeps it generally above the
International border which would almost completely dry out any
potential rainfall in Montana.
As it stands, the NBM is currently taking a middle-of-the-road
approach but leaning on the wetter side of things with most of the
precipitation falling north of a line between Helena and
Lewistown and locations in southwest Montana receiving generally
less than a tenth of a inch.
Forecaster confidence-wise, it seems more of long-range models
are pointing towards a wetter solution with the GFS remaining an
outlier for now. Early indications at the end of the 06Z NAM
confirm that there is fairly good confidence in north-central and
central Montana receiving a wetting rain. Some of the current QPF
amounts seem to be a little high but are not outside the range of
possibilities with this event. The concerning factor is if the
NAM is true, the trough is arriving much sooner than previously
expected which may potentially throw some of the current forecast
out of alignment. Right now, the confidence is that there is a
trough and it will arrive in Montana. Beyond that, the models
still have yet to agree on the finer details on how this event
will play out. -thor
&&
.AVIATION...
12/18Z TAF Period
VFR conditions will prevail over the CWA through the period. Do
expect mid/high level clouds to continue to move southeast through
the CWA through early evening. Some breezy westerly winds expected
at times this afternoon and early this evening as well. Brusda
Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 91 60 94 58 / 0 0 0 10
CTB 85 56 88 55 / 0 0 0 20
HLN 91 58 94 61 / 0 0 0 10
BZN 91 53 94 55 / 0 0 0 10
WYS 81 41 85 44 / 0 0 0 10
DLN 87 51 90 53 / 0 0 0 10
HVR 91 58 94 59 / 0 0 0 20
LWT 85 55 90 55 / 0 0 0 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls
View a Different U.S. Forecast Discussion Location
(In alphabetical order by state)
|
|
|
|