Severe Thunderstorm Warning 22, NWS Great Falls, MT

Area Forecast Discussion
National Weather Service Great Falls MT
1253 PM MDT Thu Jun 25 2026

.KEY MESSAGES...

 - Numerous showers and thunderstorms this afternoon, a few of which
   look to be on the strong side.

 - Additional showers and thunderstorms Friday and Saturday ahead
   of a cooler day on Sunday with additional precipitation into
   Monday.

 - Uncertainty remains in the exact track of the greatest
   precipitation amounts for this weekend into early next week.

&&

.DISCUSSION...

Broad upper level troughing with embedded upper level low presently
in the eastern Gulf of Alaska will continue to drift southeast
toward the Pacific Northwest through the remainder of the day and
through the end of the week. Flow aloft over the Northern Rockies
becomes increasingly southwesterly as a result, with embedded waves
ejecting from the approaching broader trough supporting several
rounds of showers and thunderstorms through Saturday.

The first wave moves through today, though there looks to be a bit
of a split regime from a parameter space perspective. Areas over
the plains looks to have the greatest instability, while areas
over Southwest Montana look to have the greatest shear. Where both
of these better parameter spaces overlap this afternoon (Most
likely between the MT-200 and I-90 corridors), there will be the
risk for large hail in the strongest thunderstorms.

Forcing increases a bit heading into Friday as the core of the
upper low approaches the Pacific NW. This forcing looks sufficient
to result in plenty of cloud cover and showers around through the
morning near the Continental Divide. This keeps confidence low
with respect for any stronger thunderstorms developing in these
areas by Friday afternoon. Areas further east have a better
opportunity to receive some daytime heating, which will be the
primary focus for afternoon thunderstorm development. While this
occurs, stronger southwesterly flow aloft looks to nudge in from
the south. This will result in gradually increasing shear from
south to north through the afternoon. Should the instability
develop in areas where the shear is able to move in quick enough,
there will be a localized risk for a stronger thunderstorm, most
favored across Central Montana east of I-15. Also worth noting
will be the risk for brief heavy downpours with the strongest
thunderstorms given anomalous moisture in place. Areas
susceptible to impacts from briefly heavy rain should be aware of
this risk, including areas around recent burn scars such as Horse
Gulch.

The increasing southwesterly flow aloft mentioned prior will also
result in a generally breezy day for most areas south of I-90 from
late Friday morning through the afternoon. The risk for impactful
gusts (58+ mph) appears low/localized at this time, however.

Additional showers and thunderstorms will be around again on
Saturday as the core of the upper low begins to translate across the
Northern Rockies. The risk for any stronger thunderstorm over the
plains and adjacent areas of Central Montana will be conditional on
how much surface moisture will be in place. Guidance that features
higher Tds, closer to 55-60F, features ample instability and shear
that would be capable of producing strong to severe thunderstorms.
Guidance that keeps Tds closer to 50F keeps instability much lower
and as a result would be result in a more run-of-the-mill type of
thunderstorm day. All that said, there is a marginal risk for severe
weather Saturday near and east of US-87.

There remains quite a bit of uncertainty with respect to the track
that the most favorable forcing for stratiform type precipitation
will take later weekend into next week. Most guidance keeps the
most favorable forcing along the Rocky Mountain Front, including
in Glacier NP. Latest trends in some guidance actually places the
better forcing west of the Continental Divide by Sunday into
Sunday night. The main takeaway will be for cooler conditions
heading into Sunday, with snow levels falling furthest where the
upper level low tracks. Cold/raw back country conditions will
exist, particularly where the greatest precipitation falls.

General troughing holds through the middle of next week, which will
keep things unsettled. Temperatures near to a touch below average
with dally opportunity for showers and thunderstorms is a reasonable
expectation at this point for this timeframe. -AM

&&

.AVIATION...
25/18Z TAF Period

Primary concern this TAF period will be for numerous showers and
thunderstorms developing across the region this afternoon and early
evening. Gusty winds, hail, and lightning will be the primary
concern from the strongest thunderstorms. Precipitation diminishes
through the late evening and overnight before developing once
again along the Continental Divide later tomorrow morning. Gusty
southwest winds slowly develop late tomorrow morning across
portions of Southwest Montana. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  53  76  51  70 /  20  70  70  50
CTB  52  69  48  68 /  30  60  40  20
HLN  56  75  51  67 /  20  80  70  80
BZN  51  78  47  65 /  30  50  70 100
WYS  42  73  40  56 /  30  30  60 100
DLN  53  74  46  62 /  10  50  70 100
HVR  50  80  51  75 /  40  50  90  40
LWT  47  76  47  67 /  50  60  70  90

&&

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

http://www.weather.gov/greatfalls

Special Weather Statement
National Weather Service Great Falls MT
247 PM MDT Thu Jun 25 2026

MTZ311-252130-
Bears Paw Mountains and Southern Blaine MT-
247 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN BLAINE...
SOUTHEASTERN HILL AND NORTHEASTERN CHOUTEAU COUNTIES THROUGH 330 PM
MDT...

At 246 PM MDT, Doppler radar was tracking a strong thunderstorm near
Parker School, or 21 miles east of Big Sandy, moving northeast at 15
mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Locations impacted include...
Parker School.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4814 10967 4824 10976 4837 10951 4817 10932
TIME...MOT...LOC 2046Z 241DEG 15KT 4821 10966

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

IG

Special Weather Statement
National Weather Service Great Falls MT
300 PM MDT Thu Jun 25 2026

MTZ320-322-323-252145-
Elkhorn and Boulder Mountains MT-
Big Belt, Bridger and Castle Mountains MT-Canyon Ferry Area MT-
300 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LEWIS AND CLARK...
WEST CENTRAL MEAGHER AND NORTHERN BROADWATER COUNTIES THROUGH 345 PM
MDT...

At 300 PM MDT, Doppler radar was tracking a strong thunderstorm 13
miles east of Montana City, or 15 miles northwest of Townsend, moving
southeast at 30 mph.

HAZARD...Wind gusts up to 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Silos, Goose Bay, and Winston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4651 11178 4661 11169 4651 11116 4629 11137
TIME...MOT...LOC 2100Z 296DEG 28KT 4652 11165

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

IG

Special Weather Statement
National Weather Service Great Falls MT
300 PM MDT Thu Jun 25 2026

MTZ320-322-323-252145-
Elkhorn and Boulder Mountains MT-
Big Belt, Bridger and Castle Mountains MT-Canyon Ferry Area MT-
300 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LEWIS AND CLARK...
WEST CENTRAL MEAGHER AND NORTHERN BROADWATER COUNTIES THROUGH 345 PM
MDT...

At 300 PM MDT, Doppler radar was tracking a strong thunderstorm 13
miles east of Montana City, or 15 miles northwest of Townsend, moving
southeast at 30 mph.

HAZARD...Wind gusts up to 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Silos, Goose Bay, and Winston.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4651 11178 4661 11169 4651 11116 4629 11137
TIME...MOT...LOC 2100Z 296DEG 28KT 4652 11165

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

IG

Special Weather Statement
National Weather Service Great Falls MT
311 PM MDT Thu Jun 25 2026

MTZ309-310-312-252200-
Eastern Pondera and Eastern Teton MT-
Western and Central Chouteau County MT-
Cascade County below 5000ft MT-
311 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL TETON...WESTERN
CHOUTEAU AND NORTHERN CASCADE COUNTIES THROUGH 400 PM MDT...

At 311 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles northeast of Power, or 22 miles northwest of Great Falls,
moving southeast at 15 mph.

HAZARD...Wind gusts up to 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This storm will remain over mainly rural areas of east central Teton,
western Chouteau and northern Cascade Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4778 11163 4789 11156 4777 11125 4764 11139
TIME...MOT...LOC 2111Z 303DEG 14KT 4779 11155

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

IG

Special Weather Statement
National Weather Service Great Falls MT
353 PM MDT Thu Jun 25 2026

MTZ304-252245-
Eastern Toole and Liberty MT-
353 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL LIBERTY COUNTY
THROUGH 445 PM MDT...

At 353 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles southeast of Lothair, or 14 miles southwest of Chester, moving
east at 10 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Locations impacted include...
Tiber Dam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4830 11124 4837 11122 4843 11092 4821 11095
TIME...MOT...LOC 2153Z 274DEG 10KT 4832 11110

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

IG

Special Weather Statement
National Weather Service Great Falls MT
401 PM MDT Thu Jun 25 2026

MTZ310-311-252300-
Western and Central Chouteau County MT-
Bears Paw Mountains and Southern Blaine MT-
401 PM MDT Thu Jun 25 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN HILL AND
NORTHEASTERN CHOUTEAU COUNTIES THROUGH 500 PM MDT...

At 401 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Big Sandy, moving northeast at 10 mph.

HAZARD...Nickel size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Locations impacted include...
St. Pierre.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4800 11002 4814 11014 4825 10986 4806 10970
TIME...MOT...LOC 2201Z 243DEG 8KT 4810 11000

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...<30 MPH

IG