377
FXUS65 KTFX 282058
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
258 PM MDT Tue Jul 28 2026

.KEY MESSAGES...

 - Smoky skies are possible through much of the week across the
   region with some impacts to air quality expected.

 - Hot temperatures will persist through the week with the hottest
   day expected on Saturday.

 - Chance for isolated to scattered thunderstorms across Southwest
   Montana Wednesday and Thursday afternoon.

 - Strong winds are possible late Saturday through Sunday with the
   strongest winds expected along the Rocky Mountain Front.

&&

.DISCUSSION...

 - Meteorological Overview:

Strong upper-level ridging will continue through the rest of the
week keeping temperatures hot and funneling more smoke from
wildfires in the PacNW into Montana. Monsoonal moisture lifting
up and around the ridge will provide daily chances for afternoon
thunderstorms with the main threat being lightning and strong
gusts. Otherwise dry conditions will persist for most areas with
low minimum relative humidity through the afternoon.

The ridge starts to break down this weekend as a strong trough
moves into the region bringing strong winds to the region,
particularly along the Rocky Mountain Front. A brief cool down is
expected for Monday before things slowly start to warm back up
again heading towards the middle of next week as another ridge
tries to build across the western CONUS.  -thor


 - Forecast Confidence & Scenarios:

Thunderstorm Chances This Week...

Isolated to scattered thunderstorms are possible Wednesday and
Thursday afternoon across Southwest Montana with some isolated
thunderstorms possible further north. The uncertainty in the
forecast centers around how thick the smoke is over the region. It
is possible the smoke could limit thunderstorm development either
partially or entirely depending on how things play out. But the
main concern is that any thunderstorm that develops will be on the
drier side which will increase fire weather concerns, especially
if there is frequent cloud to ground lightning. The potential for
severe weather remains quite low at this time but a stray gust up
to 70 mph cannot be ruled out as DCAPE is over 1500 J/kg for a
good portion of the region.

Outside of this potential most areas will remain dry through the
rest of the week.   -thor


Return of Extreme Temperatures by Saturday...

While temperatures will remain hot through the remainder of the work
week climate anomaly indicators have honed in on Saturday being the
hottest day of the upcoming week, with values becoming unusual to
very unusual with respect to late July/early August climatology. The
fact that these climate anomaly indicators are suggesting another
period of hot temperatures is remarkable considering that August 1st
is (at most locations) only one day past the climatological peak for
average high temperatures across Southwest through North Central
Montana. The table below represents the potential high temperature
scenarios for select cities across Southwest through North Central
Montana, with the "Low End" scenario being the NBM10Pct (10% chance
that temperatures are lower than the listed value), "Most Likely"
scenario being the NBM50Pct, and the "High End" scenario being the
NBM90Pct (10% chance that temperatures exceed the listed value).

                    Saturday`s High Temperature Scenarios
LOCATION               Low End | Most Likely | High End
Browning                  88   |      93     |     98
Cut Bank                  95   |     100     |    104
Havre                    103   |     108     |    111
Great Falls              102   |     105     |    107
Lewistown                 98   |     101     |    104
Helena                    97   |     100     |    104
White Sulphur Springs     95   |     102     |    101
Bozeman                   98   |      98     |    105
Dillon                    95   |      98     |    100
Ennis                     94   |      98     |    100
West Yellowstone          89   |      93     |     96

Given the presence of regional wildfires across the Northern Rockies
the "High End" scenario will be tough to reach due to decreased
solar insolation from the smoke, with dense smoke having the ability
to hold temperatures back some 5 to 10 degrees.


Strong Winds from Saturday night through Sunday...

Confidence is increasing that a period of strong, nearing high,
winds will impact the Rocky Mountain Front from Saturday night
through the day on Sunday due to the combination of mountain wave
activity (from the late evening hours on Saturday through Sunday
morning) and deep mixing (during the daylight hours on Sunday).
H700 winds per NAEFS analysis are prog`d to reach 40-50kts from
Saturday evening through Sunday morning across the aforementioned
area, which is 2 to nearly 3 standard deviations above normal. The
table below are the NBM5.0 probabilities for wind gusts to exceed
45 mph, 55 mph, and 65 mph for select locations along the Rocky
Mountain Front for the previously mentioned timeframe.

                    Probabilities for Wind Gusts to Exceed
LOCATION               >45 mph |   >55 mph   |  >65 mph
Many Glacier Valley      55%   |     15%     |    <5%
Logan Pass               50%   |     10%     |     0%
St Mary                  80%   |     40%     |    10%
Two Medicine Valley      70%   |     30%     |    10%
East Glacier             75%   |     25%     |    10%
Browning                 70%   |     25%     |     5%
Cut Bank                 75%   |     20%     |     5%
Heart Butte              80%   |     30%     |    20%
Choteau                   5%   |      0%     |     0%
Augusta                  20%   |     <5%     |     0%

Those looking to travel or recreate along the Rocky Mountain Front
should be prepared for strong winds; which could make driving and
hiking difficult, lead to falling trees in the backcountry, and/or
lead to the spread of existing/new wildfires. - Moldan

&&

.AVIATION...
28/18Z TAF Period

Wildfire smoke will continue to result in reduced surface and slant-
range visibility through the TAF period. A few showers or
thunderstorms across portions of Southwest and Central Montana this
afternoon and evening will bring a gusty and erratic wind threat.
Otherwise, minimal impacts are forecast.

For KGTF: Diurnal mixing will result in breezier westerly winds
mixing to the surface late afternoon through early evening before
becoming light and variable near and after sunset. The probability
that the westerly wind that develops this afternoon has a cross-wind
component greater than 15 kts has increased slightly to 30%. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  59  93  59  95 /   0   0   0  10
CTB  54  89  54  90 /   0   0   0   0
HLN  59  93  59  93 /   0  10  10  10
BZN  57  92  56  93 /  20  20  20  10
WYS  48  84  46  86 /  20  40  30  10
DLN  54  87  53  89 /  10  20  10  20
HVR  59  95  59  98 /   0   0   0  10
LWT  57  90  56  91 /  20   0  20  20

&&

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

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