Forecast Discussion

Issued 09/06/2026 8:10 p.m. MDT / 7:10 p.m. PDT

SHORT TERM (SUNDAY NIGHT THROUGH TUESDAY):        

      Fairly active Sunday late afternoon and evening across our region as a shortwave approaches from the south moving around the upper level low that is currently spinning across North Central Oregon and South Central Washington. The lift and instability associated with this shortwave has kicked off several strong thunderstorms initially developing across Northwest Montana but in the last couple of hours North Idaho as well as Northeast Washington have seen a rapid development of convection. Thunderstorms will continue to develop into the evening hours as the shortwave passes through then will transition to more of a stable steady rainfall as instability wanes and the forcing comes from a deformation axis of convergence on the backside of the departing upper level low. Most areas should see some very beneficial rainfall amounts with amounts ranging from around 0.50 inches all the way up to possibly 2.00 inches in some areas. While this won't be a fire season ending rainfall it will put a large dent in what has been an extremely long duration fire season thanks to the lack of snow last winter, the abundance of winter and early spring rainfall and, for much of North Idaho and Northwest Montana a record dry summer. The upper level low will pull away by Tuesday morning but some shallow instability and a weak vort max dropping southeast on the backside of the departing upper level low may kick off a couple of low topped showers Tuesday afternoon mainly across Northwest Montana. Temperatures will be very cool on Monday with widespread rainfall and many North Idaho valleys as well as most Lincoln County and far northern Sanders County valleys in Northwest Montana likely staying in the 50s all day. Snow will really not be an issue as this is not a very cold system and snow levels look to stay around 7000 feet or higher. Could see some valley fog and low stratus develop Tuesday morning especially across North Idaho valleys which will likely clear out faster than those in Northwest Montana.                

LONG TERM (TUESDAY NIGHT THROUGH SUNDAY): 

     Upper level ridging will quickly amplify once again across the Northern Rockies by Wednesday and Thursday bringing a dry and stable airmass but with all of the recent rainfall by this time, the lowering sun angle and shorter days high temperatures will likely not rise into the 80s although can't rule out some of our warmest Northwest Montana valleys (ie: Libby, Thompson Falls, Plains, etc) seeing 80 or a little warmer again especially if we get some breezes in the afternoon to mix the warmer air aloft to the surface. By late Thursday a cool upper level trough or in some models a closed low will be dropping down the British Columbia coastline and swing inland across Washington state and into the Northern Rockies by Friday and Saturday before exiting on Sunday. This system has not shown a lot of consistency as far as precipitation amounts and models are having a hard time resolving this feature. It could be that this system may end up being a rather dynamic system with some upper level jet support and may end up overperforming but will have to wait and see. This will likely be a colder system and snow will likely fall down to around 6000 feet or perhaps a bit lower with it but again still a bit too early to make predictions on that. Some valleys are likely to see frost during the late night and early morning hours this week on Wednesday and Thursday mornings and perhaps again by Sunday morning if clouds clear out in time. The combination of warm days and the upcoming cool nights and periodic precipitation chances should begin the autumnal color show put on by our trees. The seasons are changing.                            

Issued 08/26/2026 7:00 p.m. MDT / 6:00 p.m. PDT

SHORT TERM (WEDNESDAY NIGHT THROUGH FRIDAY):       

     Another very hot day across the Northern Rockies on Wednesday with temperatures running 15 to 20 degrees above late August seasonal averages and all valley locations seeing temperatures rise well into the 90s. A shortwave disturbance with associated deformation lifted north across North Idaho around noon sparking a couple of brief but intense showers and thunderstorms across Boundary County with surface based convection firing shortly thereafter across Northwest Montana. This shortwave will be out of the region by sunset and taking the shower and thunder threat with it. This system is actually the precursor to a much large pattern change that is taking place across much of the North Pacific and the North American continent that will feature much cooler conditions and increasing chances for meaningful rainfall over the next week or so. Overnight an influx of mid and high cloudiness will unfortunately make for a mild night and not the best sleeping conditions if you like to have windows open as temperatures will not drop into that comfortable territory. Cooler air will begin to move inland on Thursday along with breezy conditions as the cool upper level trough approaches the Washington coastline. Atmospheric heights and thickness values will drop on Thursday allowing for a 10 to 15 degree drop in high temperatures across the region with the larger temperature drops focused across North Idaho before spreading into Northwest Montana overnight into Friday. A stable airmass will be in place over the next few days before becoming unstable once again as the cool upper level low moves into the region this weekend. By Friday most locations will actually be down to near or a couple of degrees below late August seasonal averages which will be a welcome change after this recent hot stretch. Winds will be breezy each day from the west and southwest and by Friday a much fresher feel will be found region wide.            

LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY): 

     The first of several cool upper level closed lows will begin to push inland on Saturday increasing the chances for showers and possible thunderstorms beginning first in North Idaho by later in the day on Saturday and then across the entire region on Sunday. Temperatures will drop further on Saturday and Sunday with both days seeing high temperatures as much as 10 degrees below late August seasonal averages. Would not be surprised if some valley locations do not rise out of the 60s if heavier cloud cover and more frequent showers pass overhead any particular location. Temperatures will feel more like early Autumn and with breezy westerly winds it will feel much fresher than it has in several months and a very welcome change. While overall precipitation amounts are not anticipated to be very much, areas that see a heavier shower or thunderstorm could see up to 0.25 inches of rain which would be very welcome as any precipitation would be a blessing at this point. By Monday and Tuesday a transient shortwave ridge will migrate across the region and with the cool airmass left in the wake of the departing upper level low some of our typical colder valleys such as Yaak, McGinnis Meadows, Happys Inn, Priest Lake and others could see frost on Monday and perhaps Tuesday mornings so be aware if you live in one of those colder locations. By Wednesday then next cool closed upper level low will be pushing inland within the mean long wave upper level trough which will be anchored and held in place by a strong upper level ridge in the center of the country and also across the Central Pacific. This will spread more stratiform precipitation into North Idaho during the afternoon hours and eventually into Northwest Montana as well by late in the day. Too early to say how much precipitation this system may bring us but it does look wetter than this weekends system for a much larger region. Temperatures will drop down to around 10 to 15 degrees below early September seasonal averages just beyond this forecast period which will feel almost chilly given the length of our recent warm to hot spell. For those of you who do not like 90 degrees days it is very likely that after Thursday none of our valley locations will see 90 degrees again until next year some time. The cooler and potentially wetter weather will be great news for our local and regional wildfires and will hopefully begin to see the season winding down. A season ending precipitation event is not currently forecasted but this could change. CPC's 6-10 and 8-14 day outlooks show the Northern Rockies with temperatures leaning to likely below average and precipitation leaning to likely above average, just what the doctor ordered! Stay tuned. 

Issued 08/24/2026 6:25 p.m. MDT / 5:25 p.m. PDT

SHORT TERM (MONDAY NIGHT THROUGH WEDNESDAY):       

     Well most of us saw at least some rainfall over the weekend with some experiencing some rather strong thunderstorms with hail and strong winds especially around Noxon and Trout Creek Saturday afternoon and then overnight into early Sunday morning across much of North Idaho. Unfortunately as is typically the case with our elevated, dynamically driven convection in our area these thunderstorms moved along fairly quickly limiting the amount of rainfall they were able to put down but it did end Sandpoint's record breaking streak of 40 consecutive days without any measurable rainfall with a total of 0.05 inches recorded, truly remarkable for North Idaho and much of Northwest Montana! The region remains unfortunately exceptionally dry and a return to hot and dry conditions is already underway as of this writing on Monday late afternoon. A surface high will be sliding down along the east side of the Continental Divide overnight into Tuesday morning while a corresponding thermal trough deepens across Central Washington beneath the upper level ridge axis. This will induce a light northeasterly surface pressure gradient which will cause northeast winds to surface in the typical spots overnight into Tuesday morning. The winds will not be very strong but where they do surface overnight temperatures will not cool off very much and relative humidity values will not recover which is not good news. A very hot, dry and unstable airmass will be overhead on Tuesday as the ridge axis crosses overhead and drags the thermal trough with it placing our region squarely beneath this unseasonably hot airmass. Don't think any records will be broken on Tuesday or Wednesday for that matter but it will be hot. A weak upper level disturbance will move into Central Idaho and Southwest Montana Tuesday night and continue moving north on Wednesday. This feature may provide enough lift and instability to fire off a few showers and thunderstorms throughout the day on Wednesday but I am not very confident this will provide much convection or beneficial precipitation to very many although if you do get fortunate enough to see a thunderstorm develop overhead then you could pick up some very heavy rain in a short amount of time. Temperatures on Wednesday are a bit of a low confidence forecast. The atmosphere will still be very warm to hot but the cloud cover will play a huge role in how hot our region actually gets. If there is an abundance of mid and high cloudiness then forecast high temperatures for Wednesday will be too warm. If you like the hot weather then Wednesday may very well be your last day to enjoy hot temperatures in the 90s until next summer as some significant changes are looking increasingly likely to come later this week. Read below for more details.         

LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY): 

     An approaching upper level low will be moving into Northwest Washington and Southwest BC later Wednesday night into Thursday morning which is what may help the weak upper level disturbance rotating around the Continental Ridge to give our area some evening and possibly overnight convection Wednesday night into early Thursday morning, possibly very similar to what we saw on Sunday morning. At the very least this cooler upper level trough will bring temperatures down around 10 or so degrees on Thursday from Wednesday's hot readings but they will still be above late August seasonal averages which are now in the upper 70s to mid 80s across our valley areas in North Idaho and Northwest Montana. Winds will also pick up and be breezy but nothing too strong at this point. While this is occurring a rather cold, arctic upper level low will be moving across Alaska and moving southeast on the front side of a developing Bering Sea upper level ridge. As this cold arctic upper level low shifts southeast it will pick up a shortwave in the Gulf of Alaska and swing it southeast along the BC coastline by Friday while also allowing colder air from the Northwest Territories and Yukon to get pulled into this upper level low. The EC model was the first model to pick up on this several days ago and now the EC, GFS and Canadian models are all showing a rather cool and dynamic upper level low moving southeast along the BC coastline before swinging inland this weekend across Northwest Oregon bringing the entire Pacific Northwest and Northern Rockies region a significant pattern change and a taste of early fall. With a strong mid Pacific ridge looking to build confidence in this upper level low dropping far enough south along with a potent jet that looks to spin up between the incoming upper level low and the hot Continental Ridge  looks to provide enough lift, instability and dynamics to generate our first widespread wetting rainfall across the entire region since late June. While this is still a ways out confidence continues to increase especially since now the American and Canadian models seem to have come on board with this significant pattern change. A lot can still change but this forecaster is hopefully optimistic this change will occur given our incredibly dry summer our region has experienced this year. One final note, if you are planning any camping or hiking in the high country this upcoming weekend pay close attention to the forecasts over the next few days as this cold upper level low is showing signs of lowering snow levels perhaps down as low as 6500 feet.