Prolonged cold and wet system on the way

The cold breezes and wisps of snow that arrived in Montana this week look set to continue.

With a full week of summer remaining, a cold air mass has already driven down the Flathead Valley’s temperatures, helping tame area fires and providing Big Sky Country’s upper reaches a taste of winter. More could be on the way.

The National Weather Service’s Missoula office projects a “long-lasting cold, wet weather system” to arrive early Monday, keeping “precipitation and cold temperatures in the forecast for much of the week.”

The agency’s seven-day forecast for Glacier Park International Airport shows temperatures inching up over the next few days, reaching a high of 66 on Sunday. They’re then expected to dip and range between the 30s and 50s for much of next week, with at least some chance of rain throughout that time.

Meanwhile, it says that “snow levels will dip below 6,000 feet (high confidence), and could be as low as 4,000 feet at times Monday night and Tuesday (less confidence).” It cautions that “wet and raw conditions with snow accumulations on mountain passes/backcountry roads will be the main concerns.”

Some motorists have already faced those conditions. Glacier National Park’s Logan Pass had a dusting at the Visitor Center’s parking lot and Going-to-the-Sun Road was closed Friday morning from from Big Bend to Siyeh Bend due to winter weather conditions.

The section of the road between foot of Lake McDonald and Siyeh Bend is closed due to the Sprague Fire.

Mountain passes near Helena and Butte picked up considerable accumulation. Great Divide Ski Area near Helena reported 6 inches of snow as of Friday morning.

“The ending time of this system is still yet to be determined,” the Weather Service concluded, “since this appears to be a multifaceted large-scale pattern.”