Issued Sunday June 1, 2025 6:55 P.M. MDT

Tonight…Fair skies and cooler except for increasing clouds towards morning north and east of Lake Koocanusa with scattered showers developing. Snow level near 6000 feet across the Whitefish Range. Areas of frost possible in colder valleys. Lows in the lower 30s to lower 40s with near 40 around 5000 feet. Light wind except ridge top winds northwest 10 to 20 mph.

Monday…Considerable cloudiness in the morning with scattered rain and snow showers east of Lake Koocanusa then partly cloudy in the afternoon. Mostly sunny elsewhere in the morning then partly cloudy in the afternoon. Snow level near 6000 feet in the morning along the Whitefish Range. Local snow accumulations of up to 1 inch possible above 6500 feet in the Whitefish Range. Highs in the mid 60s to mid 70s with mid 50s around 5000 feet. Northwest winds 5 to 15 mph.

Monday night…Partly cloudy in the evening then fair skies and cool overnight. Areas of frost developing in the valleys. Lows in the upper 20s to upper 30s except mid 40s in thermal belts on slopes and hillsides with lower 40s around 5000 feet. Light wind.

Tuesday…Mostly sunny and seasonal. Highs in the upper 60s to upper 70s with upper 50s around 5000 feet. Afternoon west to southwest winds 10 to 15 mph with gusts to 20 mph across ridge tops.

EXTENDED OUTLOOK (WEDNESDAY THROUGH SUNDAY):

Wednesday through Sunday…Unseasonably dry and warm except for a slight chance of mountain showers Saturday. Lows in the upper 30s to upper 40s except mid 50s in thermal belts on slopes and hillsides with near 50 around 5000 feet. Highs in the 70s to near 80 Wednesday warming to the upper 70s to upper 80s Thursday through Sunday. Around 5000 feet highs in the lower 60s Wednesday warming to near 70 by Saturday and Sunday.

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

ISSUED 06/01/2025 7:45 P.M. MDT/6:45 P.M. PDT

SHORT TERM (SUNDAY NIGHT THROUGH TUESDAY):

A dry and stable upper level trough that moved over the region on Sunday finally brought daytime temperatures back down close to seasonal averages although still a couple of degrees warmer than typical for the first day of June. If you were up earlier on Sunday then you may have noticed an all too familiar sky for our summer months with an orange glow to it, wildfire smoke that was transported into our region from large wildfires burning in Manitoba and Saskatchewan. The surface low that helped to bring our gusty winds on Saturday lifted northeast into these Canadian provinces overnight with our region on the backside of the low and flow coming down from the north helped to move some of that smoke into our region. It has since cleared out. Another weak shortwave will drop down in northwest flow late tonight into Monday morning. Most of the lift and dynamics will remain over and east of the Continental Divide unfortunately so not much in the way of rainfall for our region with the exception perhaps of far northeast Lincoln County up around Rexford, Eureka and Trego as these areas will be closest to the shortwaves passage. Elsewhere just some passing cloud cover. Temperatures for the next two nights and mornings will be chilly, cold enough for frost and even freezing conditions in our typically colder valleys especially in Northwest Montana such as Yaak, Happys Inn and McGinnis Meadows. These colder valleys may dip into the upper 20s however having said that the average last frost date for these colder valleys is typically not until the second week of June. Elsewhere with the threat of frost away from the shorelines of larger lakes such as Thompson, Pend Oreille, Priest, Cocolalla to name a few, is there so gardeners may want to take precautions to protect sensitive plants. Once the Monday shortwave passes through the region by afternoon upper level ridging will build to our west and bring northwest flow aloft into the region with slowly warming temperatures, dry conditions and a stable environment, not really what our region needs right now.

LONG TERM (TUESDAY NIGHT THROUGH SUNDAY):

Dry and stable conditions will continue across the region throughout much of the upcoming week with little to no sign of any shortwave passages, instability and therefore precipitation. Ridging looks to remain somewhat flat which will allow for breezy conditions with passing shortwaves just north of the Canadian border but yet strong enough to also prevent the lift and instability associated with these features to also be kept further north. The result is an extremely dry and somewhat warm start to what is historically one of the wettest months of the year for our region, and, in the case of parts of Northwest Montana the wettest month of the year. If we look out into fantasy land there are not really any clear signals of a pattern change showing up at this time. That being said, we did have a cooler and somewhat unsettled pattern for about 2-3 weeks in May that unfortunately did not bring much widespread rainfall but still at least brought some rainfall. We have just closed out the first week of this dry stretch and so if pattern recognition holds and then we can expect about another 2 weeks of warm and dry conditions before potentially seeing the pattern flip back to a wetter and cooler one. Time will tell. Unfortunately fire danger will continue to increase and finer fuels are already beginning to cure and dry out, almost 6 weeks earlier than typical. For all of the newer arrivals to the region, despite all of the rain than fell this past winter, that rain fell on frozen ground which did not soak into the soils and therefore simply ran off into the lakes and rivers which did not do any benefit as our lakes and rivers are kept at lower levels during the winter and spring months before being raised to summer levels. Another reason why our region benefits from snowfall during the winter months and not rain.