Forecast Discussion

In-Depth Weather Discussion for Northwest Montana/North Idaho/Northern Rockies 

Issued 11/27/2025 6:50 p.m. MST / 5:50 p.m. PST

SHORT TERM (THURSDAY NIGHT THROUGH SATURDAY):

     As was suggested a couple of days ago the warmer air really never made it much into our part of the Northern Rockies with snow being the primary precipitation type across all of Bonner, Boundary, Lincoln and Sanders Counties thanks to a surface high located across Eastern British Columbia/Western Alberta. The cool air associated with the surface high helped to keep low level winds light northeasterly which is a cold direction for us this time of year and although temperatures aloft slowly warmed throughout the day they remained below freezing which was expected. The sounding from our region actually shows very nicely what is called an isothermal layer meaning that temperatures from the surface up through the atmosphere are at or below freezing which allowed snowfall to be the primary precipitation type. Snow advisories have been issued by NWS Missoula for our Northwest Montana areas with valleys likely to see 2 to 4 additional inches of snowfall below 4000 feet and mountains likely to see 3 to 6 inches above 4000 feet. Similar numbers will be found across North Idaho but as of this writing on Thanksgiving evening no advisories have been issued by NWS Spokane. If you are headed out early on Friday be prepared for slippery and possibly snow covered roads if they are not treated as the snowfall overnight will likely be moderate at times and the ground is finally beginning to freeze which will make things especially slippery. The surface low responsible for the precipitation today will begin to slide by to our south overnight which will help pull lower atmospheric heights and thickness values further south causing colder temperatures. In addition the surface high that has been located across southern Canada will slide south into North Central Montana which will tighten the northeasterly surface pressure gradient. Expect northeast winds to pick up by Friday morning and blow steadily throughout the day in the usual locations with the strongest winds likely to remain across ridge tops, through portions of the Clark Fork River Valley, along portions of Lake Koocanusa and through the Purcell Trench especially around Sandpoint. Some lighter northeast winds will be found elsewhere too but these will subside after sunset on Friday night while the other locations will keep the breezy conditions through Saturday late in the day. Winds won't be terribly strong but noticeable with bite to the air. The colder and drier modified polar airmass will likely help keep stratus and freezing fog to a minimum on Saturday morning but won't completely eliminate it in the more typical valleys sheltered from the wind. Saturday should be a fairly nice day with seasonal or even a bit chilly conditions with at least some filtered sunshine although a bluebird winter day is not likely with a shortwave dropping southeast well to our west across Washington. Northeast winds will begin to diminish by late in the day on Saturday wherever they continue to blow setting the stage for the coldest night of the season on Sunday morning.       

LONG TERM (SATURDAY NIGHT THROUGH THURSDAY):

     The Northern Rockies will remain on the western flank of a large and very cold Hudson Bay low that will largely remain anchored across Manitoba driving some rather cold air southward into the Midwest throughout much of this period. Strong upper level ridging will reside off the Washington coast with the resulting north to northwesterly upper level steering flow allowing various shortwaves to drop into our region and bringing in occasional chances for snow. The strongest of these features looks to arrive later Monday into Tuesday and could bring a few inches of snow to our area in the valleys and perhaps twice that amount to the mountains. Several other weak features will move through during the remainder of the period but trying to time these out with any sort of accuracy this far out is silly at best so have simply broad brushed the extended forecast period with chances for snow showers. Temperatures will see a slow moderation back to near seasonal averages which is mid 30s for valley locations at the beginning of December. Mountains will remain well below freezing so with the combination of the recent and expected snowfall as well as cold temperatures for good snow-making conditions should be able to see our two larger resorts of Schweitzer and Big Mountain be able to open up sometime next week. Check their websites for updates and keep checking back here for the latest forecasts.

Issued 11/23/2025 7:05 p.m. MST / 6:05 p.m. PST

SHORT TERM (SUNDAY NIGHT THROUGH TUESDAY):

     Shortwave that brought some light amounts of rain and higher elevation snow earlier on Sunday has exited the region with another approaching shortwave lifting northeast through Northern Central Oregon as of this writing. This feature is already beginning to increase shower coverage across the Palouse region in Eastern Washington with the rain and snow overspreading the region overnight before exiting east on Monday morning. This shortwave will also help drive the colder upper level low inland causing our snow levels to finally crash rapidly down to all valley floors by sunrise on Monday although by this time much of the lift with the departing shortwave will also have exited as well. Higher elevations above around 4500 feet should see anywhere from 2 to 4 inches of snow with perhaps up to an inch above 3500 feet and even a dusting is possible on some valley floors early Monday morning and perhaps again later in the day on Monday with any lingering instability snow showers. A surface low will deepen over and just east of the Continental Divide and coupled with strong cold air advection will drive some breezy west to southwest winds overnight into the early afternoon hours on Monday before winds begin to subside. Shallow upper level ridging will begin to build off to our west placing lower atmospheric heights and thickness values across the Northern Rockies and with mostly clear skies prior to any stratus and freezing fog development on Tuesday morning, all locations will finally have a hard freeze unless stratus and freezing fog develops sooner but thinking there will be enough mixing during the day and evening hours on Monday to prevent stratus from developing until around dawn on Tuesday. The only locations that may escape a hard freeze Tuesday morning could be those along the immediate shoreline of Pend Oreille Lake in North Idaho  as the water temperatures are still in the mid 40s with the mild fall we have had thus far. Even these locations should still get down to if not a few degrees below freezing but maybe not into the 20s as everyone else will. Colder valleys will drop into the teens especially in Northwest Montana. Tuesday will see shallow upper level ridging build across the region with an anticyclonically curved jet riding just to the north of the International Border. Some uncertainty if the placement of the jet will allow a shortwave to topple over it and bring increasing clouds along with some snow showers. If they do occur these look to be very light and overall little accumulation. Up until early this morning models were showing this incoming system to potentially be more impactful but with the shortwave running into the mean ridge position and the supporting upper level low well displaced to the north and west the drier scenario looks more likely. Temperatures will cool a bit on Tuesday and areas that keep persistent freezing fog and low clouds on Tuesday will struggle to get much above freezing.                  

LONG TERM (TUESDAY NIGHT THROUGH SUNDAY):

 * POTENTIAL OF 1ST MAJOR COLD OUTBREAK OF THE SEASON NEXT WEEKEND *

     Another shortwave will round the offshore trough on Wednesday and develop good warm air advection precipitation across the region. The position of the surface low off the Washington and Oregon coast however will help drive some cold air damming across the Northern Rockies such that models such as the GFS and ICON are both holding onto colder air longer and thus show higher snowfall totals across our region on what is traditionally a very busy travel day so if you do have travel plans it will be wise to keep up to date on the forecast as there is the potential for some accumulating snowfall across all elevations. This is a set up where there will most likely be a messy changeover to rain at some point either later Wednesday or on Thanksgiving Day itself although some of the more recent models have begun to trend cooler and track the surface low further to the south. If this solution holds true then snow levels will remain lower on valley floors and if the ICON model is correct the Thanksgiving holiday could be a snowy one. Preliminary estimates on snowfall totals from Wednesday morning through Thanksgiving Day are as follows:

Valleys(below 4000 feet): 1-4 inches

Mountains(above 4000 feet) 3 to 6 inches

These numbers could go up or down as we get closer depending on what solution proves to be true.

     After the Thanksgiving holiday things begin to turn much more interesting and potentially snowy followed by our first polar outbreak of the season. The GFS has been the leading model on advertising this potential pattern change as early as a week ago with the Canadian and EC-AI model also catching on now. The EC standard model is not completely onboard yet but the 12Z run did show some trending towards the colder solution. Ridging begins to amplify offshore likely due to the placement of the MJO(Madden Julian Oscillation) which looks to be now moving into Phase Space 7 in the West Pacific judging from tropical convection in that region. An update from the CPC will come out on Monday further highlighting this development. At this time of year a MJO in Phase Space 7 strongly correlates to much colder temperatures and stormy conditions across the Northwest and Northern Rockies and this may be what the GFS model has picked up on. Given that the MJO is destructively interfering with the La Nina base state in the tropical Pacific the added warm waters in the West Pacific with the eastward moving MJO helps to drive strong vertical motion in the atmosphere and therefore cause a large amplification of the jet stream across the North Pacific. That being said a dynamic shortwave looks to drop southeast along the coast of British Columbia late Thanksgiving Day and move through our region on Friday bringing lower snow levels and colder temperatures. This does not currently look like a strong storm but still one that will likely produce widespread accumulating snowfall across all elevations. The parent and I might add, very cold upper level low will be migrating by this time southwest from the high arctic north of Hudson Bay in Canada and setting up shop across Northern and Central Manitoba and Saskatchewan with the trough axis shifting toward the Northern Rockies. With a strongly amplifying upper level ridge across the Gulf of Alaska and the Yukon this will allow for strong and cold northerly flow to drop down through British Columbia and Alberta before potentially plunging into the Northern Rockies. Temperatures look to drop substantially on Saturday and could begin to also see some strong northeast winds developing by this time across the region. By Sunday the EC-AI model shows some impressive cold temperatures just to the east of the Continental Divide where there will likely be true arctic air sliding south with "high" temperatures in those locations possibly well below zero. This cold air looks to be deep enough to spill across the Continental Divide and across all of the Northern Rockies. As of now the more conservative approach puts high temperatures by next Sunday in our region anywhere from the mid to high teens in Northwest Montana to the lower to mid 20s across North Idaho. The colder solutions such as the GFS if it is correct would drop those temperatures by a solid 10 degrees or more. Will also likely be seeing some areas dropping well below zero by next Sunday depending on cloud cover and winds. Either way a dramatic change to a very winter-like and much colder pattern is on the horizon. The main question really is how cold and how much snow will fall. Also with Sunday historically being another very busy travel day be prepared for winter-like driving conditions and very cold temperatures. With as mild as this autumn season has been this cold will be especially impactful if it does occur. Stay tuned!