Marine Weather and Tide Forecast for Big Sky, MT
May 7, 2024 11:17 AM MDT (17:17 UTC) Change Location
 | Sunrise 6:00 AM Sunset 8:41 PM Moonrise 4:36 AM Moonset 7:41 PM |
Area Discussion for - Great Falls, MT
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FXUS65 KTFX 071549 AFDTFX
Area Forecast Discussion National Weather Service Great Falls MT 949 AM MDT Tue May 7 2024
SYNOPSIS
An impactful spring weather system will bring widespread rain, mountain snow, and strong gusty winds though early Thursday. The most impactful conditions will occur over the Central ranges and their neighboring northerly foothills, where the combination of strong winds and heavy snow will cause blizzard conditions at times. High pressure moves in towards the weekend for moderating temperatures and drier conditions.
UPDATE
Updated forecast is out. The high wind warning for the Kings Hill area has been cancelled. The rest of the high wind highlights remain as is. Expect periodic mixing of winds down from aloft today, resulting in some wind gusts of 60 to 70 mph over the portion of the CWA Heavy rain and high mountain snow has developed in the Bears Paw mountains, where over 2 inches of liquid have been reported. 1 to 2 inches of additional liquid is expected at lower elevations over North Central MT through Wed, with up to 4 inches of liquid in the mountains. With that amount of liquid, some minor flooding is possible. Brusda
AVIATION
540 AM MDT Tue May 7 2024 (07/12Z TAF Period)
A strong northwesterly flow aloft will keep widespread low level wind shear, mountain wave turbulence, and strong northwest surface winds across North Central (KCTB KHVR), Central (KLWT KGTF KHLN), and Southwest (KBZN KEKS KWYS) Montana though at least 08/12Z. High Wind Warnings are in effect for much of the area.
The system responsible for these winds will also continue to spread rain and mainly mountain snow and blowing snow southwest over the terminals through 21Z, lowering mostly low VFR conditions to at least widespread mountain-obscuring MVFR/IFR by then. An increase in precipitation intensity will further worsen conditions further to mostly LIFR by around 03Z over much of North Central and Central Montana. Winter Weather Warnings/Advisories are in effect for mountain areas and areas adjacent to them. -Coulston
Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information.
HYDROLOGY
Heavy rainfall in the Bears Paw mountains will result in minor flooding on Beaver Creek and possibly Clear Creek. Flood highlights are in effect for portions of North Central MT. Brusda
PREV DISCUSSION
/ISSUED 540 AM MDT Tue May 7 2024/
A deepening mid - level low will remain over the plains of Eastern Montana and Western N/S Dakota through Thursday, placing North- central and Southwest Montana in a favorable position for extended periods of lower elevation rains, mountain snow, and strong gusty north to northwesterly winds. Rain over the eastern/northern portions of the plains will continue to slowly retrograde to the southwest today, reaching Southwest Montana by this afternoon/evening. Newer model guidance has trended to more of a northerly flow aloft for Tuesday night into Wednesday for an overall westward shift/expansion of the heaviest core of rainfall (1 to 3 inches) deeper into Central/North-central, but areas along and east/southeast of a Havre to Great Falls line are favored to see the higher 2+ inch totals according to current trends and NBM probabilistic forecasts. This widespread rainfall will be beneficial, but there will be at least some hydrologic concerns to deal with. Please see the hydrology section for more information.
As previously advertised, colder air aloft, along with this system's dynamics and orographic north to northwesterly upslope flow will result in periods of moderate to heavy mountain snow.
Nearly all mountain ranges in the forecast area are now covered under winter highlights, with the exception of Western Beaverhead County. Areas over and near the central ranges, namely the Little Belt and Highwood Mountains are still progged to see the highest snowfall amounts and overall greatest impacts. Probabilistic guidance still supports snowfall amounts in the 1 to 2 feet range with wind gusts routinely above 40 mph. The Rocky Mountain Front, Big Belts/Bridgers, and the Madison/Gallatin Ranges will also see higher end snow totals and potential impacts. As a mater of fact, the Madison/Gallatin zone 330 was upgraded to a Winter Storm Warning to address the increased synoptic favorability for heavier snow.
There are a few lower elevation areas that may see at least a period of impacts from wet snow, most notably over the northerly upslope areas along the MT highway 200 corridor in between Great Falls and Lewistown. The current Winter Weather Advisory here covers the concerns for this area as do the advisories in effect for the remainder of the mountain areas not under warnings, but I did delay the start time for these advisories to this evening, closer to when the impacts are expected. I also considered upgrading the Bear's Paw Mountain zone to a Winter Storm Warning with snow totals nearing 8 inches or so over the peaks, but decided against it with warmer air actually moving in from the north tonight into Wednesday.
Winds were initially a little slower to develop than anticipated, but have started to increase during the overnight hours and that trend will continue into Tuesday with a tightening pressure gradient and H700 flow increasing and peaking in the 50 to 60 kt range this afternoon. The current High Wind Warnings handle the situation reasonably well and more or less match NBM probabilistic guidance, so no changes were made to these products.
The greatest impacts from rains, mountain snow, and winds will occur between Tuesday afternoon and Wednesday morning before things slowly tapper off and becoming more showery in nature Wednesday afternoon through early Thursday. Ensemble then favor the low pressure system moving towards the south and weakening, with high pressure building into the Northern Rockies for drier conditions and temperatures warming above average this weekend.
- RCG
PRELIMINARY POINT TEMPS/POPS
GTF 46 34 43 37 / 100 100 100 80 CTB 45 33 44 34 / 100 100 90 20 HLN 49 37 46 39 / 70 100 100 60 BZN 48 31 44 32 / 60 100 100 80 WYS 42 24 44 27 / 70 90 80 40 DLN 46 31 47 35 / 20 80 90 40 HVR 48 38 57 40 / 100 100 90 50 LWT 39 29 40 33 / 100 100 100 90
TFX WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Fergus County below 4500ft-Hill County-Judith Basin County and Judith Gap-Northern Blaine County-Snowy and Judith Mountains-Western and Central Chouteau County.
Winter Storm Warning until midnight MDT Wednesday night for Big Belt, Bridger and Castle Mountains-East Glacier Park Region- Snowy and Judith Mountains-Southern Rocky Mountain Front.
Winter Weather Advisory from 6 PM this evening to 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty.
High Wind Warning until midnight MDT tonight for Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Elkhorn and Boulder Mountains-Gates of the Mountains-Helena Valley-Meagher County Valleys-Upper Blackfoot and MacDonald Pass.
Blizzard Warning until midnight MDT Wednesday night for Little Belt and Highwood Mountains.
Winter Weather Advisory from 6 PM this evening to noon MDT Wednesday for Cascade County below 5000ft-Fergus County below 4500ft-Judith Basin County and Judith Gap.
Winter Weather Advisory from 6 PM this evening to midnight MDT Wednesday night for Elkhorn and Boulder Mountains-Upper Blackfoot and MacDonald Pass.
High Wind Warning until 6 PM MDT this evening for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.
Winter Storm Warning from 6 PM this evening to midnight MDT Wednesday night for Gallatin and Madison County Mountains and Centennial Mountains.
Flood highlights for portions of North Central MT until further notice.
Area Forecast Discussion National Weather Service Great Falls MT 949 AM MDT Tue May 7 2024
SYNOPSIS
An impactful spring weather system will bring widespread rain, mountain snow, and strong gusty winds though early Thursday. The most impactful conditions will occur over the Central ranges and their neighboring northerly foothills, where the combination of strong winds and heavy snow will cause blizzard conditions at times. High pressure moves in towards the weekend for moderating temperatures and drier conditions.
UPDATE
Updated forecast is out. The high wind warning for the Kings Hill area has been cancelled. The rest of the high wind highlights remain as is. Expect periodic mixing of winds down from aloft today, resulting in some wind gusts of 60 to 70 mph over the portion of the CWA Heavy rain and high mountain snow has developed in the Bears Paw mountains, where over 2 inches of liquid have been reported. 1 to 2 inches of additional liquid is expected at lower elevations over North Central MT through Wed, with up to 4 inches of liquid in the mountains. With that amount of liquid, some minor flooding is possible. Brusda
AVIATION
540 AM MDT Tue May 7 2024 (07/12Z TAF Period)
A strong northwesterly flow aloft will keep widespread low level wind shear, mountain wave turbulence, and strong northwest surface winds across North Central (KCTB KHVR), Central (KLWT KGTF KHLN), and Southwest (KBZN KEKS KWYS) Montana though at least 08/12Z. High Wind Warnings are in effect for much of the area.
The system responsible for these winds will also continue to spread rain and mainly mountain snow and blowing snow southwest over the terminals through 21Z, lowering mostly low VFR conditions to at least widespread mountain-obscuring MVFR/IFR by then. An increase in precipitation intensity will further worsen conditions further to mostly LIFR by around 03Z over much of North Central and Central Montana. Winter Weather Warnings/Advisories are in effect for mountain areas and areas adjacent to them. -Coulston
Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information.
HYDROLOGY
Heavy rainfall in the Bears Paw mountains will result in minor flooding on Beaver Creek and possibly Clear Creek. Flood highlights are in effect for portions of North Central MT. Brusda
PREV DISCUSSION
/ISSUED 540 AM MDT Tue May 7 2024/
A deepening mid - level low will remain over the plains of Eastern Montana and Western N/S Dakota through Thursday, placing North- central and Southwest Montana in a favorable position for extended periods of lower elevation rains, mountain snow, and strong gusty north to northwesterly winds. Rain over the eastern/northern portions of the plains will continue to slowly retrograde to the southwest today, reaching Southwest Montana by this afternoon/evening. Newer model guidance has trended to more of a northerly flow aloft for Tuesday night into Wednesday for an overall westward shift/expansion of the heaviest core of rainfall (1 to 3 inches) deeper into Central/North-central, but areas along and east/southeast of a Havre to Great Falls line are favored to see the higher 2+ inch totals according to current trends and NBM probabilistic forecasts. This widespread rainfall will be beneficial, but there will be at least some hydrologic concerns to deal with. Please see the hydrology section for more information.
As previously advertised, colder air aloft, along with this system's dynamics and orographic north to northwesterly upslope flow will result in periods of moderate to heavy mountain snow.
Nearly all mountain ranges in the forecast area are now covered under winter highlights, with the exception of Western Beaverhead County. Areas over and near the central ranges, namely the Little Belt and Highwood Mountains are still progged to see the highest snowfall amounts and overall greatest impacts. Probabilistic guidance still supports snowfall amounts in the 1 to 2 feet range with wind gusts routinely above 40 mph. The Rocky Mountain Front, Big Belts/Bridgers, and the Madison/Gallatin Ranges will also see higher end snow totals and potential impacts. As a mater of fact, the Madison/Gallatin zone 330 was upgraded to a Winter Storm Warning to address the increased synoptic favorability for heavier snow.
There are a few lower elevation areas that may see at least a period of impacts from wet snow, most notably over the northerly upslope areas along the MT highway 200 corridor in between Great Falls and Lewistown. The current Winter Weather Advisory here covers the concerns for this area as do the advisories in effect for the remainder of the mountain areas not under warnings, but I did delay the start time for these advisories to this evening, closer to when the impacts are expected. I also considered upgrading the Bear's Paw Mountain zone to a Winter Storm Warning with snow totals nearing 8 inches or so over the peaks, but decided against it with warmer air actually moving in from the north tonight into Wednesday.
Winds were initially a little slower to develop than anticipated, but have started to increase during the overnight hours and that trend will continue into Tuesday with a tightening pressure gradient and H700 flow increasing and peaking in the 50 to 60 kt range this afternoon. The current High Wind Warnings handle the situation reasonably well and more or less match NBM probabilistic guidance, so no changes were made to these products.
The greatest impacts from rains, mountain snow, and winds will occur between Tuesday afternoon and Wednesday morning before things slowly tapper off and becoming more showery in nature Wednesday afternoon through early Thursday. Ensemble then favor the low pressure system moving towards the south and weakening, with high pressure building into the Northern Rockies for drier conditions and temperatures warming above average this weekend.
- RCG
PRELIMINARY POINT TEMPS/POPS
GTF 46 34 43 37 / 100 100 100 80 CTB 45 33 44 34 / 100 100 90 20 HLN 49 37 46 39 / 70 100 100 60 BZN 48 31 44 32 / 60 100 100 80 WYS 42 24 44 27 / 70 90 80 40 DLN 46 31 47 35 / 20 80 90 40 HVR 48 38 57 40 / 100 100 90 50 LWT 39 29 40 33 / 100 100 100 90
TFX WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Fergus County below 4500ft-Hill County-Judith Basin County and Judith Gap-Northern Blaine County-Snowy and Judith Mountains-Western and Central Chouteau County.
Winter Storm Warning until midnight MDT Wednesday night for Big Belt, Bridger and Castle Mountains-East Glacier Park Region- Snowy and Judith Mountains-Southern Rocky Mountain Front.
Winter Weather Advisory from 6 PM this evening to 6 AM MDT Wednesday for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty.
High Wind Warning until midnight MDT tonight for Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Elkhorn and Boulder Mountains-Gates of the Mountains-Helena Valley-Meagher County Valleys-Upper Blackfoot and MacDonald Pass.
Blizzard Warning until midnight MDT Wednesday night for Little Belt and Highwood Mountains.
Winter Weather Advisory from 6 PM this evening to noon MDT Wednesday for Cascade County below 5000ft-Fergus County below 4500ft-Judith Basin County and Judith Gap.
Winter Weather Advisory from 6 PM this evening to midnight MDT Wednesday night for Elkhorn and Boulder Mountains-Upper Blackfoot and MacDonald Pass.
High Wind Warning until 6 PM MDT this evening for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains-Southern Rocky Mountain Front.
Winter Storm Warning from 6 PM this evening to midnight MDT Wednesday night for Gallatin and Madison County Mountains and Centennial Mountains.
Flood highlights for portions of North Central MT until further notice.
| Airport | Dist | Age | Wind kt | Vis | Sky | Weather | Temp | DewPt | RH | inHg |
| KEKS ENNIS BIG SKY,MT | 18 sm | 22 min | W 19G24 | 10 sm | Overcast | 43°F | 19°F | 39% | 29.72 |
Billings, MT,
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