“Tonight into Tuesday morning, we expect 4-8 inches of additional snow over mountain passes, except MacDonald and Homestake passes, which will receive less,” NWS said in a Feb. 2 press release.

Valley locations mostly in western Montana are expected to see light snow with some melting and refreezing overnight, which could cause icy road conditions by Monday morning, Feb. 9.

NWS also warns about a potential storm on Tuesday night and Wednesday.

“Confidence is below average for this event due to model inconsistencies,” NWS said. “Due to a possible resurgence of arctic air and a low pressure system moving through southern Idaho, it is now likely that the southern Bitterroot Valley and northern Lemhi County eastward through Georgetown Lake, Anaconda, and Butte will at least have light snow with a few inches accumulation. However, an outside chance remains of a high impact event with 6 inches or more affecting these areas.”

A heavy rain event could impact Northwest Montana on Friday and Saturday.

“You may be familiar with the terms atmospheric river or pineapple express,” NWS aid. “This will be one of those kinds of events.”

NWS expects the biggest impacts will be in central Idaho, where 1-2 inches of rain in is expected in Idaho and Clearwater counties over 24-36 hours.

“Rising streams may be of some concern, but we are not yet concerned with flooding,” NWS said. “The heavy rain will likely cause some rock and mud slides in the typical areas and may affect roads.”

NWS said significant snow is possible on mountain passes, with a transition from snow to rain and back to snow possible at the passes.

“At this lead time there is still uncertainty, but confidence with this system is above average,” NWS said.

The National Weather Service in Missoula forecasts a series of three weather systems that will impact Central Idaho and Western Montana.

“Tonight into Tuesday morning, we expect 4-8 inches of additional snow over mountain passes, except MacDonald and Homestake passes, which will receive less,” NWS said in a Feb. 2 press release.

Valley locations mostly in western Montana are expected to see light snow with some melting and refreezing overnight, which could cause icy road conditions by Monday morning, Feb. 9.

NWS also warns about a potential storm on Tuesday night and Wednesday.

“Confidence is below average for this event due to model inconsistencies,” NWS said. “Due to a possible resurgence of arctic air and a low pressure system moving through southern Idaho, it is now likely that the southern Bitterroot Valley and northern Lemhi County eastward through Georgetown Lake, Anaconda, and Butte will at least have light snow with a few inches accumulation. However, an outside chance remains of a high impact event with 6 inches or more affecting these areas.”

A heavy rain event could impact Northwest Montana on Friday and Saturday.

“You may be familiar with the terms atmospheric river or pineapple express,” NWS aid. “This will be one of those kinds of events.”

NWS expects the biggest impacts will be in central Idaho, where 1-2 inches of rain in is expected in Idaho and Clearwater counties over 24-36 hours.

“Rising streams may be of some concern, but we are not yet concerned with flooding,” NWS said. “The heavy rain will likely cause some rock and mud slides in the typical areas and may affect roads.”

NWS said significant snow is possible on mountain passes, with a transition from snow to rain and back to snow possible at the passes.

“At this lead time there is still uncertainty, but confidence with this system is above average,” NWS said.