371
FXUS65 KTFX 281729
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1129 AM MDT Sat Jun 28 2025

Aviation Section Updated.

.KEY MESSAGES...

- There will be isolated to scattered showers and thunderstorms
  along the Hi Line this afternoon.

- There will be a dry period and a slight warm up in temperatures
  from Sunday through Wednesday.

- Daily chances for precipitation for the week return Wednesday.

&&

.UPDATE...
/Issued 1005 AM MDT Sat Jun 28 2025/

No major changes made with this morning`s update. Still expecting
a few showers and maybe some thunderstorms to develop along the
Hi-Line, but that is covered well in the existing forecast. Ludwig

&&

.DISCUSSION...
/Issued 1005 AM MDT Sat Jun 28 2025/

 - Meteorological Overview:

Zonal flow aloft continues today. This will continue to bring breezy
winds across the region. A mini disturbance in the afternoon will
bring isolated to scattered showers and thunderstorms along the
Hi-Line region. Weak CAPE and shear will keep storms sub-severe
today. Sunday, an upper level ridge will build in for the
beginning of the week. This will help keep the region dry and
slightly warm up temperatures through Wednesday. On Wednesday,
broad troughing with an opening upper-level wave in California
will advect in moisture in the area. A series of upper-air
disturbances will bring daily chances for showers and
thunderstorms through the rest of the week. These daily chances
of precipitation will help moderate temperatures to near or
slightly above seasonable.


 - Forecast Confidence & Scenarios:

Precipitation amounts with showers this afternoon will mostly stay
under 0.05", with up to 0.10" with a heavier shower. Models have
been consistent on the drier period towards the beginning of the
week. Temperatures will start out above average. There`s a 50-90%
chance for 90 degree temperatures extending from the Bozeman Valley
through the Helena valley, then through and along the Missouri
and Milk River Valley Tuesday and Wednesday. Daily chances for
precipitation after Wednesday should help moderate temperatures.
With an increase in moisture, temperatures, and deep layer shear
next week, we will have to monitor the development of some
stronger storms with convection. -Wilson

&&

.AVIATION...
28/18Z TAF Period

VFR conditions will prevail at all terminals during this TAF period.
At the KWYS terminal there is a 10 - 15% chance for thunderstorms
between 29/00Z and 29/02Z. At the KCTB and KHVR terminals there is a
15 - 50% chance for showers and thunderstorms between 28/19Z and
29/02Z. Across all terminals during at least a portion of this TAF
period there will be gusty winds. During the first 6 hours of this
TAF period there will instances of mountain wave turbulence across
North-central Montana. -IG

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  77  49  80  52 /  10   0   0   0
CTB  72  47  77  49 /  50  20   0   0
HLN  79  50  82  52 /  10   0   0   0
BZN  82  46  82  47 /  10   0   0   0
WYS  75  37  75  36 /  10  20   0   0
DLN  78  43  78  46 /  10   0   0   0
HVR  80  50  80  50 /  20  30   0   0
LWT  72  47  74  49 /   0   0   0   0

&&

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

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