103
FXUS65 KTFX 100524
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1124 PM MDT Wed Jul 9 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Hot, dry, and breezy conditions through this evening.

 - Winds, with gusts of between 40 to 50 mph, will be strongest
   along the Rock Mountain Front through this evening.

 - Showers and thunderstorms through this evening will produce
   gusty and erratic winds.

 - Temperatures cool into the day on Thursday, with a better
   chance for rainfall.

&&

.UPDATE...
/Issued 835 PM MDT Wed Jul 9 2025/

High-based thunderstorms are decreasing this evening with any
lingering showers and isolated lightning expected to dissipate by
midnight. Gusty and erratic winds are still likely as this
activity continues to diminish through the remainder of this
evening, but the risk for gusts in excess of 50 mph has likely
ended. Weak cooling aloft and the passage of a surface trough
east of the area will allow for slightly cooler temperatures
tonight with the more widespread breezy/windy conditions across
the north-central MT plains also decreasing overnight.
Breezy/windy conditions redevelop early Thursday before a Canadian
cold front and noticeably cooler airmass move south across the
area Thursday afternoon/evening. Hoenisch

&&

.DISCUSSION...
/Issued 835 PM MDT Wed Jul 9 2025/

Upper level ridge over the Northern Rockies will be broken down as a
longwave trough, currently moving over the western seaboard of the
CONUS/Canada, slides east through the day on Thursday. At the
surface a Pacific front, which was moving over the Pacific Northwest
this morning, will move across Southwest through North Central
Montana during the evening hours tonight. Strong warm air advection
ahead of the advancing shortwave and attendant Pacific front will
once again push high temperatures across Southwest through North
Central Montana some 10 to 15 degrees above normal, with highs over
the plains (below 3500 feet in elevation) of Central and North
Central Montana peaking in excess of 95 degrees today. Isolated
showers and thunderstorms through the morning and early afternoon
hours, which will be predominately on the dry side, will become more
widely scattered through the late afternoon and evening hours as the
aforementioned Pacific front approaches. Given high cloud bases and
very dry air in the low to mid-levels (i.e. inverted-V sounding) any
shower and thunderstorm through this evening will be capable of
producing strong and erratic winds on top of the already increasing
westerly surface winds. These breezy and gusty west surface winds
ahead of the Pacific front will be especially strong along the Rocky
Mountain Front and immediate eastern plains out to the I-15 corridor
in Central and North Central Montana, with frequent gusts of
between 40-50 mph occurring here. In addition to these winds, a
few of the showers and thunderstorms will be on the strong to
severe side, with gusts in excess of 50-60 mph possible, mainly
along and east of a Great Falls to Butte line.

By Thursday morning a potent shortwave rotating through the overall
longwave trough axis will begin to dive southeast from British
Columbia and over the Northern Rockies. This shortwave and a re-
enforcing cold front will help to bring cooler conditions to all of
the Northern Rockies on Thursday, along with scattered to numerous
showers and isolated thunderstorms. Snow levels across Glacier
National Park will fall to as low as 8500feet through Thursday
evening, which could lead to a dusting of snow over the highest
peaks across the park. Surface winds in wake of the re-enforcing
cold front will shift to the northwest and north, with another period
of strong and gusty winds expected through the day on Thursday,
especially in the north-south orientated valleys of Southwest and
Central Montana.

Quasi-zonal to northwest flow through the remainder of the work
week, weekend, and early next week will lead to fluctuating
temperatures and periods of dry and wet conditons. - Moldan/Ludwig

&&

.AVIATION...
10/10Z TAF Period

Isolated showers and thunderstorms will continue to dissipate
through 09z Thursday along and southeast of a KHLN to KLWT line,
but not impacts to terminals are expected. Smoke/haze from
wildfires burning across the Pacific Northwest and Southwest
Canada will move east and over North Central Montana ahead of the
next upper level disturbance, impacting the KCTB and KHVR
terminals through the early morning hours on Thursday. Main impact
from this smoke/haze will be reductions in slantwise visibility
upon ascent/descent. Otherwise, showers and thunderstorms will
begin to overspread North Central and Central Montana beyond 18z
Thursday as a re-enforcing cold front pushes southeast from
Alberta. This front will bring increasing winds and a shift to
more of the northwest, along with an increase in mid-level cloud
cover. Mountain obscuration will begin to increase beyond 18z
Thursday from northwest to southeast.
- Moldan

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

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  59  83  47  79 /  10  20  20   0
CTB  56  72  42  77 /  10  50  20   0
HLN  59  84  50  81 /  30  10  10   0
BZN  52  87  49  80 /  30  10  30  10
WYS  42  78  41  73 /  20  10  20  30
DLN  49  83  47  77 /  30   0  10   0
HVR  57  82  47  80 /  10  30  10   0
LWT  55  82  43  73 /  40  10  30  10

&&

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

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