Marine Weather and Tide Forecast for Big Sky, MT
 | Sunrise 7:56 AM Sunset 4:42 PM Moonrise 3:57 AM Moonset 1:46 PM |
Marine Forecasts
NOTE: Zones were updated 3/20/2025. If your report is out of date, please click Edit
7 Day Forecast for Marine Location Near Big Sky, MT
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FXUS65 KTFX 152324 AFDTFX
Area Forecast Discussion National Weather Service Great Falls MT 424 PM MST Mon Dec 15 2025
Aviation Section Updated.
KEY MESSAGES
- Strong, gusty winds peak along the Rocky Mountain Front this afternoon and then over central and north-central Montana later this evening through early Tuesday.
- A dynamic Pacific front brings widespread strong to damaging winds and locally intense snow showers on Wednesday.
- The colder air sags southward into north-central Montana for the second half of the week while mostly mountain snow.
DISCUSSION
/Issued 302 PM MST Mon Dec 15 2025/
- Meteorological Overview:
Weak ridging aloft will maintain well above normal temperatures today while strong cross barrier flow and mountain wave activity maintain periods of strong, gusty winds along the Rocky Mountain Front and much of north-central MT through Tuesday morning. H700 flow will roughly run between 60 and 80 kts with mountain waves transferring the strongest winds to the surface along the Rocky Mountain Front through this evening and a shortwave passage bringing peak winds over the plains this evening through early Tuesday.
Height falls and cooling aloft will bring slightly cooler, but still above average temperatures on Tuesday with winds diminishing some by the afternoon hours. Pacific moisture streaming towards the Continental Divide will bring periods of light snow to the immediate eastern slopes of the Rocky Mountain Front. Otherwise, Tuesday looks rather tranquil compared to what's coming on Wednesday.
The well advertised potent Pacific trough and attendant cold front is still progged to sweep through the state on Wednesday and bring at least a several hour period of widespread strong, to damaging winds. This system will be driven by strong cold air advection and H850/H700 flow in the 55 to 85 kt range, both of which look to occur during peak diurnal mixing. The sharp frontogenesis with this system quickly drops H700/H500 temperatures to around -15C/-30C behind the front, encouraging scattered locally intense snow shower/squall development. The central and southwest mountain passes look to be the target for the most impacts from this convective snow activity Wednesday morning/early afternoon and then it shifts to along the Hi- Line in the evening hours per the Canadian Front. There will also be ongoing snow along the higher terrain of the Rocky Mountain Front that become heavy at times Tuesday night into Wednesday, particularly above pass level.
Colder air will briefly clip northern areas on Thursday in the wake of the passing trough/cold front before milder air moves back in ahead of the next Pacific trough. There will be a couple of Pacific troughs that traverse the Northern Rockies through early next week. Each will bring a period of increased mostly mountain snow followed by modest intrusions of Arctic air, primarily clipping northern areas. Timing for these trough/cold fronts look to be late Thursday through early Saturday and again Sunday into Monday. - RCG
- Forecast Confidence & Scenarios:
Periods of strong winds along the Rocky Mountain Front and central/north-central MT through Tuesday morning...
Strongest winds this afternoon will continue to favor the Rocky Mountain Front and the plains along and west of highway 89 where wind gusts are exceeding the 75 to 90 mph range at times. The normally wind prone locations such as Bynum, Deep Creek, and East Glacier/Browning areas will be most prone to gusts exceeding 90 mph.
Farther east, the strongest winds look to occur with the ejecting shortwave trough this evening through early Tuesday when 50 to 70 mph gusts will be more common.
The main uncertainty with this event is the nighttime peak of upper level winds possibly reducing the occurrence of stronger gusts mixing to the surface. This will be most pronounced over some of the more wind protected valleys, including the Milk River Valley vicinity. Higher end probabilities (70%+) for gusts over 55 mph are a little spottier here, but given some of these areas already reached high wind criteria and the upper level flow strengthens tonight during the shortwave passage, at least localized warning criteria gusts seem plausible. The secondary uncertainty will be central and southern areas along and north of the I90 corridor. Some of these mountain passes may have brief periods with gusts exceeding 60 mph as will the Canyon Ferry area. Left these locations out of the warning for now given limited opportunity and lower end probabilities (generally less than 50%) for gusts over 55 mph.
Impacts will continue to include difficult to dangerous travel for high profile vehicles, localized blowing dust near open fields, and the movement of unsecured outdoor items, including Christmas decorations. Additional power outages also can't ruled out, particularly for areas that observe the higher end gusts.
Widespread strong to damaging winds and localized intense snow showers/squall on Wednesday...
Conditions continue to be favorable for a widespread strong to damaging wind event across southwest and central/north-central MT on Wednesday. Strong cold air advection and peak H700 flow in the 60 to 90 kt range looking to occur during maximum diurnal mixing is concerning at this point to say the least. Some caveats that would weaken or preclude the winds such as a stronger/faster Canadian front undercutting the strong winds aloft and shifts in frontal passage timing are starting to lose steam. Just of note, H850 winds behind the Canadian front are now highlighting north/northwesterly H850 winds in excess of 50 kts. Additionally, this event look to be of longer duration (multiple hours of very windy conditions vs the typical 1-3 hr peak period). Given the wide swath of 60 to 80 mph wind gusts expected, impacts look to include difficult to dangerous travel for high profile vehicles, downed trees/property damage, and scattered power outages. All the watches for Wednesday have been upgraded to a warnings and now include the entire forecast area.
In addition to the winds, there will be sufficient instability and dynamics for locally intense snow shower/squalls, particularly for central and southwest Montana. Moderate to heavy snow will also be ongoing along the higher terrain of the Northern Rocky Mountain Front and a brief period of gusty accumulating snow may even work its way southward to the Hi-Line Wednesday evening via the Canadian cold front. - RCG
AVIATION
16/00Z TAF Period
VFR conditions will prevail across all terminals during the duration of this TAF Period. It will be very windy at the KGTF, KCTB, and KHVR terminals from now through about 16/18Z. From now through 16/14Z there will be wind gusts in excess of 55 kts at the KCTB terminal and 45 kts at the KGTF terminal. There will be instances of low-level wind shear and mountain wave turbulence during the duration of this TAF Period across North-central, Central, and Southwestern Montana. -IG
HYDROLOGY
Mild daytime and overnight temperatures will lead to rapid melting of the recent snow across eastern portions of north-central MT. With initially frozen ground, much of the snowmelt is likely to remain on the surface and may lead to standing water. While overall impact to creek/stream levels is low, most creeks are likely to be frozen with potential for water flow over the ice or potentially back up in some creek bottoms. Hoenisch
PRELIMINARY POINT TEMPS/POPS
GTF 42 52 40 50 / 0 10 20 60 CTB 35 45 33 45 / 10 10 40 50 HLN 38 52 36 48 / 20 20 30 90 BZN 36 55 36 51 / 10 20 10 90 WYS 24 40 30 39 / 10 30 50 100 DLN 37 54 36 47 / 10 10 10 90 HVR 30 44 30 43 / 0 20 30 50 LWT 36 46 34 48 / 10 10 10 60
TFX WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 11 AM MST Tuesday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft- Eastern Pondera and Eastern Teton-Fergus County below 4500ft- Hill County-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Northern Blaine County- Snowy and Judith Mountains-Upper Blackfoot and MacDonald Pass- Western and Central Chouteau County.
High Wind Warning from 3 AM Wednesday to midnight MST Wednesday night for Bears Paw Mountains and Southern Blaine-Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Cascade County below 5000ft-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Elkhorn and Boulder Mountains-Fergus County below 4500ft- Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Gates of the Mountains-Helena Valley-Hill County-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Meagher County Valleys- Missouri Headwaters-Northern Blaine County-Northern High Plains- Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains-Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.
Winter Storm Watch from Tuesday evening through Wednesday evening for East Glacier Park Region-Southern Rocky Mountain Front.
High Wind Warning until 8 AM MST Tuesday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Eastern Toole and Liberty-Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.
Area Forecast Discussion National Weather Service Great Falls MT 424 PM MST Mon Dec 15 2025
Aviation Section Updated.
KEY MESSAGES
- Strong, gusty winds peak along the Rocky Mountain Front this afternoon and then over central and north-central Montana later this evening through early Tuesday.
- A dynamic Pacific front brings widespread strong to damaging winds and locally intense snow showers on Wednesday.
- The colder air sags southward into north-central Montana for the second half of the week while mostly mountain snow.
DISCUSSION
/Issued 302 PM MST Mon Dec 15 2025/
- Meteorological Overview:
Weak ridging aloft will maintain well above normal temperatures today while strong cross barrier flow and mountain wave activity maintain periods of strong, gusty winds along the Rocky Mountain Front and much of north-central MT through Tuesday morning. H700 flow will roughly run between 60 and 80 kts with mountain waves transferring the strongest winds to the surface along the Rocky Mountain Front through this evening and a shortwave passage bringing peak winds over the plains this evening through early Tuesday.
Height falls and cooling aloft will bring slightly cooler, but still above average temperatures on Tuesday with winds diminishing some by the afternoon hours. Pacific moisture streaming towards the Continental Divide will bring periods of light snow to the immediate eastern slopes of the Rocky Mountain Front. Otherwise, Tuesday looks rather tranquil compared to what's coming on Wednesday.
The well advertised potent Pacific trough and attendant cold front is still progged to sweep through the state on Wednesday and bring at least a several hour period of widespread strong, to damaging winds. This system will be driven by strong cold air advection and H850/H700 flow in the 55 to 85 kt range, both of which look to occur during peak diurnal mixing. The sharp frontogenesis with this system quickly drops H700/H500 temperatures to around -15C/-30C behind the front, encouraging scattered locally intense snow shower/squall development. The central and southwest mountain passes look to be the target for the most impacts from this convective snow activity Wednesday morning/early afternoon and then it shifts to along the Hi- Line in the evening hours per the Canadian Front. There will also be ongoing snow along the higher terrain of the Rocky Mountain Front that become heavy at times Tuesday night into Wednesday, particularly above pass level.
Colder air will briefly clip northern areas on Thursday in the wake of the passing trough/cold front before milder air moves back in ahead of the next Pacific trough. There will be a couple of Pacific troughs that traverse the Northern Rockies through early next week. Each will bring a period of increased mostly mountain snow followed by modest intrusions of Arctic air, primarily clipping northern areas. Timing for these trough/cold fronts look to be late Thursday through early Saturday and again Sunday into Monday. - RCG
- Forecast Confidence & Scenarios:
Periods of strong winds along the Rocky Mountain Front and central/north-central MT through Tuesday morning...
Strongest winds this afternoon will continue to favor the Rocky Mountain Front and the plains along and west of highway 89 where wind gusts are exceeding the 75 to 90 mph range at times. The normally wind prone locations such as Bynum, Deep Creek, and East Glacier/Browning areas will be most prone to gusts exceeding 90 mph.
Farther east, the strongest winds look to occur with the ejecting shortwave trough this evening through early Tuesday when 50 to 70 mph gusts will be more common.
The main uncertainty with this event is the nighttime peak of upper level winds possibly reducing the occurrence of stronger gusts mixing to the surface. This will be most pronounced over some of the more wind protected valleys, including the Milk River Valley vicinity. Higher end probabilities (70%+) for gusts over 55 mph are a little spottier here, but given some of these areas already reached high wind criteria and the upper level flow strengthens tonight during the shortwave passage, at least localized warning criteria gusts seem plausible. The secondary uncertainty will be central and southern areas along and north of the I90 corridor. Some of these mountain passes may have brief periods with gusts exceeding 60 mph as will the Canyon Ferry area. Left these locations out of the warning for now given limited opportunity and lower end probabilities (generally less than 50%) for gusts over 55 mph.
Impacts will continue to include difficult to dangerous travel for high profile vehicles, localized blowing dust near open fields, and the movement of unsecured outdoor items, including Christmas decorations. Additional power outages also can't ruled out, particularly for areas that observe the higher end gusts.
Widespread strong to damaging winds and localized intense snow showers/squall on Wednesday...
Conditions continue to be favorable for a widespread strong to damaging wind event across southwest and central/north-central MT on Wednesday. Strong cold air advection and peak H700 flow in the 60 to 90 kt range looking to occur during maximum diurnal mixing is concerning at this point to say the least. Some caveats that would weaken or preclude the winds such as a stronger/faster Canadian front undercutting the strong winds aloft and shifts in frontal passage timing are starting to lose steam. Just of note, H850 winds behind the Canadian front are now highlighting north/northwesterly H850 winds in excess of 50 kts. Additionally, this event look to be of longer duration (multiple hours of very windy conditions vs the typical 1-3 hr peak period). Given the wide swath of 60 to 80 mph wind gusts expected, impacts look to include difficult to dangerous travel for high profile vehicles, downed trees/property damage, and scattered power outages. All the watches for Wednesday have been upgraded to a warnings and now include the entire forecast area.
In addition to the winds, there will be sufficient instability and dynamics for locally intense snow shower/squalls, particularly for central and southwest Montana. Moderate to heavy snow will also be ongoing along the higher terrain of the Northern Rocky Mountain Front and a brief period of gusty accumulating snow may even work its way southward to the Hi-Line Wednesday evening via the Canadian cold front. - RCG
AVIATION
16/00Z TAF Period
VFR conditions will prevail across all terminals during the duration of this TAF Period. It will be very windy at the KGTF, KCTB, and KHVR terminals from now through about 16/18Z. From now through 16/14Z there will be wind gusts in excess of 55 kts at the KCTB terminal and 45 kts at the KGTF terminal. There will be instances of low-level wind shear and mountain wave turbulence during the duration of this TAF Period across North-central, Central, and Southwestern Montana. -IG
HYDROLOGY
Mild daytime and overnight temperatures will lead to rapid melting of the recent snow across eastern portions of north-central MT. With initially frozen ground, much of the snowmelt is likely to remain on the surface and may lead to standing water. While overall impact to creek/stream levels is low, most creeks are likely to be frozen with potential for water flow over the ice or potentially back up in some creek bottoms. Hoenisch
PRELIMINARY POINT TEMPS/POPS
GTF 42 52 40 50 / 0 10 20 60 CTB 35 45 33 45 / 10 10 40 50 HLN 38 52 36 48 / 20 20 30 90 BZN 36 55 36 51 / 10 20 10 90 WYS 24 40 30 39 / 10 30 50 100 DLN 37 54 36 47 / 10 10 10 90 HVR 30 44 30 43 / 0 20 30 50 LWT 36 46 34 48 / 10 10 10 60
TFX WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 11 AM MST Tuesday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft- Eastern Pondera and Eastern Teton-Fergus County below 4500ft- Hill County-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Northern Blaine County- Snowy and Judith Mountains-Upper Blackfoot and MacDonald Pass- Western and Central Chouteau County.
High Wind Warning from 3 AM Wednesday to midnight MST Wednesday night for Bears Paw Mountains and Southern Blaine-Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Cascade County below 5000ft-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Elkhorn and Boulder Mountains-Fergus County below 4500ft- Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Gates of the Mountains-Helena Valley-Hill County-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains-Madison River Valley-Meagher County Valleys- Missouri Headwaters-Northern Blaine County-Northern High Plains- Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains-Snowy and Judith Mountains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass-Western and Central Chouteau County.
Winter Storm Watch from Tuesday evening through Wednesday evening for East Glacier Park Region-Southern Rocky Mountain Front.
High Wind Warning until 8 AM MST Tuesday for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Eastern Toole and Liberty-Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.
Link to 1 hour of 5 minute data for KBZN
Terminal Aerodrome Forecast (TAF) for KBZN
Wind History Graph: BZN
(wind in knots)
GEOS Local Image of northern rockey
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