Issued Sunday July 20, 2025 9:40 A.M. PDT

Rest of Today…Variable cloudiness with isolated showers and thunderstorms north and west of Highway 2 and Highway 95. Highs in the mid 70s to lower 80s with near 60 around 6000 feet. West to southwest winds 10 to 20 mph.

Tonight…Considerable cloudiness with isolated to widely scattered showers developing after midnight, most numerous west of Highway 95. Lows in the 50s with mid 40s around 6000 feet. Light wind.

Monday…Mostly cloudy and cooler with showers likely. Isolated afternoon thunderstorms. Locally heavy rainfall possible. Highs in the 60s with near 50 around 6000 feet. Light wind.

Monday night…Showers likely with isolated evening thunderstorms. Locally heavy rainfall possible. Areas of fog developing. Lows in the 50s with mid 40s around 6000 feet. Light wind.

Tuesday…Areas of fog in the early morning otherwise mostly cloudy with showers likely and scattered afternoon thunderstorms. Locally heavy rainfall possible. Highs in the mid 60s to lower 70s with lower 50s around 6000 feet. Light wind.

EXTENDED OUTLOOK (WEDNESDAY THROUGH SUNDAY):

Wednesday through Sunday…No precipitation with seasonal temperatures. Lows in the mid 40s to mid 50s except lower 60s in thermal belts on slopes and hillsides with near 50 around 6000 feet. Highs in the upper 70s to mid 80s with mid 60s around 6000 feet.

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

ISSUED 07/13/2025 7:45 P.M. MDT/6:45 P.M. PDT

SHORT TERM (SUNDAY NIGHT THROUGH TUESDAY):

Another hot and dry day across the region on Sunday with most valley locations away from and upwind from the larger lakes seeing their temperatures soar into the 90s or 10 to 15 degrees above seasonal averages. This will only make the changes coming in about 24 to 36 hours even more brutal to bear as temperatures on Tuesday will be 10 to 20 degrees below seasonal averages for mid July and with a brisk northeast wind will make it feel very fresh indeed. A cold (for July) upper level trough is currently pushing into British Columbia as of this writing on Sunday evening and will begin to drop southeast through the province overnight into the day on Monday. As this system approaches surface pressures will fall along the Continental Divide on Monday morning allowing for a breezy day with west to southwest winds to develop. Monday will still be very warm and anywhere from 5 to 10 degrees above average for mid July. Here are the main takeaways from this unusually strong summer system:

* Showers and thunderstorms will begin to develop along the Canadian border Monday afternoon and progress southward as convergence and instability increases along with strong jet dynamics associated with the incoming strong vort max and upper level trough. These convective showers will likely begin to organize into a more consolidated area of rain overnight with the focus occurring over Northwest Montana.

* Snow levels, yes you read that correctly, will drop to between 7,000 to 7,500 feet overnight into Tuesday morning across Northwest Montana with the Whitefish Range and to a lesser extent the Cabinet Mountains seeing accumulating snowfall at the highest elevations. Anticipate between 2 to 4 inches to fall across the highest peaks above 7,500 feet.

* Rainfall totals look to be between 0.25 to 0.75 inches with local amounts up to 1.00 inch across Northwest Montana especially across Lincoln County with the lower amounts likely across Sanders County. Across North Idaho rainfall totals look to be between 0.10 inches to 0.30 inches with local amounts over 0.50 inches where thunderstorms occur and along the Montana border.

* Strong northeast winds late Monday into early Tuesday morning. Northeast winds will dramatically increase in the typical areas such as through the Purcell Trench in North Idaho between Elmira and the Kootenai County line, across Northwest Montana through the Clark Fork River Valley especially between Noxon and Heron, Bull Lake, Highway 2 between Libby and Troy, Lake Koocanusa and the Tobacco Valley. Winds in these areas will likely become sustained for a time between 25 to 40 mph with gusts to 50 mph possible. Winds could gust over 60 mph across higher elevations. Elsewhere in the typically non windy areas expect northeast winds of 15 to 25 mph with local gusts to 30 mph at times.

* Temperatures will drop from the mid 80s to mid 90s Monday to the upper 50s to near 70 in the valleys on Tuesday with brisk northeast winds. Across higher terrain above 6000 feet temperatures near 70 on Monday will drop to the mid to upper 40s on Tuesday with brisk northeast winds and wind chills in the lower to mid 30s.

* Frost potential? Colder Northwest Montana valleys and even an isolated spot or two in North Idaho away from the shoreline of Priest Lake and in portions of Selle Valley could see frost on Wednesday morning and to a lesser extent on Thursday morning. Northwest Montana valleys that are likely to see frost are Yaak, Trego, Olney, south of Libby near the airport, McGinnis Meadows, Happys Inn and possibly near Trout Creek. By Thursday morning only the Yaak and McGinnis Meadows areas are likely to have the threat of frost.

LONG TERM (TUESDAY NIGHT THROUGH SUNDAY):

Uncertainty in the long term portion of the forecast as models are a bit split as to what the eventual pattern will set up as with outcomes ranging from upper level ridging to broad and weak troughing with ridging remaining offshore. For now with so much attention being paid to the short term broad brushed the long term forecast as a more middle of the road type with temperatures returning to above average readings but not as warm as the warmer ridge scenarios would suggest. Gut feeling is that the ridge axis may remain well to the west along the West Coast or even offshore allowing for broad and cooler northwest upper level flow to remain in place allowing periodic shortwaves to pass through. Should this solution prove correct conditions would become more unsettled and chances for periodic showers and thunderstorms will need to be reintroduced to the forecast. For now have kept things dry and will see how things play out after the significant weather event passes by Tuesday night.