Marine Weather and Tide Forecast for Big Sky, MT

DISCUSSION
/Issued 320 AM MST Sun Nov 8 2026/

- Meteorological Overview:

This morning, the upper level ridge of high pressure breaks down, resulting in a tightening pressure gradient over Montana. This creates windy conditions today, mainly across North-Central MT.
The strongest winds will be along the eastern slopes of the Rocky Mountain Front, where favorable thermal conditions exist for mountain wave development. This, combined with diurnal heating, will allow the stronger winds aloft to mix down to the surface, creating the possibility of isolated 100 MPH gusts along the Front. The remainder of North-Central MT will see gusts closer to 65 MPH. By this evening, the winds will have greatly dissipated, as the remainder of the aforementioned ridge moves east and we transition to zonal flow aloft across the state. This will result in slightly cooler, but still seasonally average, temperatures Monday and Tuesday.

Increased moisture aloft will be transported along the zonal flow, resulting in the chance of light precipitation over the higher elevations of the Northern Rockies this evening through tomorrow morning. Snow levels will lower down to around 4000 ft north of Lincoln, creating the potential for a light dusting of snow over Marias Pass. For the rest of the CWA, this increased moisture aloft will simply manifest as cloudy skies.

On Tuesday, the zonal flow aloft gets pushed eastward by a shortwave trough digging southward through southwest MT. This will create a tightening surface pressure gradient, producing another day of windy conditions across Central and North-Central MT. Once again, the strongest winds will be along the Rocky Mountain Front.
By Wednesday, a strong upper level ridge will have built over the Idaho Panhandle, putting the region under its influence and subsequently allowing temperatures to rise. Through the rest of the forecast period, the ridge will slowly move eastward until Montana sits roughly along its axis, allowing for the continued trend of seasonally warm temperatures and little to no chance of precipitation. -Dzomba

- Forecast Confidence & Scenarios:

Sounding and cross sectional analysis was showing increased upper level winds, as well as favorable thermal conditions for mountain wave development along the Rocky Mountian Front. This analysis, along with model guidance, was supporting upper level winds as strong as 100 MPH mixing down to the surface by late Sunday morning across the Front, as well as upper level winds as strong as 60-70 MPH mixing down to the surface across the rest of North- Central MT. As such, the high wind warning for the Rocky Mountain Front was updated to communicate gusts around 95 MPH being expected, with isolated gusts near 100 MPH being possible.

While average 850 mb - 700 mb winds do not look as strong throughout the rest of North-Central MT, they are still around 65 MPH, with just 700 mb winds peaking around 70 MPH. Model guidance also shows strong winds spreading across the Hi-Line, with chances for pockets of stronger winds along Highway 87. As such, the high wind watches have been upgraded to high wind warnings and have been expanded to include the rest of North-Central MT. However, these high wind warnings are for lesser winds, with gusts up to 65 MPH expected. -Dzomba

AVIATION
08/12Z TAF Period

Another round of very strong and gusty winds across central and north central MT including KCTB, KHVR, KGTF, and KLWT. For KCTB and KHVR, there will be much stronger winds aloft of 50-60 KT at and above 1500 FT AGL with the strongest probability for LLWS between 08/12Z to 08/16Z. Probability for LLWS over KGTF and KLWT is lower however if sufficient decoupling of the lower atmosphere occurs with surface winds going below 10 KTS then LLWS is likely.
Some gusty winds out of the southwest are expected for KEKS, KBZN, KWYS, and KHLN however only up to 25 KT to 30 KT.

VFR conditions will prevail across the region for the period.
Primary hazards will be LLWS and mountain wave turbulence over and up to 50 NM downrange of the Rocky Mountain Front. - Akins



PRELIMINARY POINT TEMPS/POPS
GTF 63 40 57 42 / 0 0 0 0 CTB 55 32 51 37 / 0 0 0 0 HLN 62 35 54 36 / 0 0 10 0 BZN 60 32 54 34 / 0 0 0 0 WYS 48 24 49 26 / 0 0 0 10 DLN 59 31 55 33 / 0 0 0 0 HVR 65 34 53 35 / 0 0 0 0 LWT 64 36 56 38 / 0 10 0 0

TFX WATCHES/WARNINGS/ADVISORIES
High Wind Warning until 8 PM MST this evening for East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains.

High Wind Warning from 8 AM this morning to 8 PM MST this evening for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft-Eastern Pondera and Eastern Teton-Eastern Toole and Liberty-Hill County-Judith Basin County and Judith Gap- Northern Blaine County-Western and Central Chouteau County.