584
FXUS65 KTFX 100235
AFDTFX

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

.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...

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 542 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

Scattered high-based showers and thunderstorms tracking ENE
across central and southwest MT this evening will bring gusty and
erratic winds to some central/southwest MT terminals with a 5-15%
probability for gusts in excess of 50kts for areas east of a
Helena to Havre line. Breezy west/southwest winds continue
through the evening across the North-Central MT plains with
showers/T-storms diminishing overnight. On Thursday, breezy west
to northwest winds develop at most terminals by mid-day with a
wind shift to the north occurring from north to south across the
area Thursday afternoon, followed by an increase in mid-level
clouds and perhaps some showers at KCTB and KHVR.

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