Posted: Oct 20, 2012 4:45 PM by Meteorologist Mike Heard
The first good winter type storm system is expected Monday and Tuesday across western Montana. Colder air from the Gulf of Alaska is currently digging into the pacific NW and begins to move across Montana Sunday.
A broad trough opens up and the jet stream will push a stronger storm system through the pacific NW and northern Rockies by Monday. The combination of cooler air aloft and a healthy moisture stream off the Pacific ocean will produce accumulating snow over the mountain passes Monday night into Tuesday and should be fairly widespread.
There is uncertainty on snow accumulations for the lower valleys early next week and it will come down to temperatures. Monday night and early Tuesday morning lows will be cold enough for valley snow to develop but afternoon highs are expected to climb into the lower 40's and thus a mix of rain/snow is possible.
The National Weather Service will most likely start issuing a winter storm watch for NW Montana Sunday in anticipation of this approaching storm system.
The broad trough will continue to keep the overall weather pattern cool and unsettled Wednesday and Thursday with scattered snow showers off and on and accumulations are possible over the mountains and mountain passes.
Forecast models are beginning to show another good storm system pushing into Montana next weekend. We will continue to monitor the models and we should have a better idea on timing and intensity of this storm event in the coming days.
Starting Monday look for wintry travel conditions to set up across the state and continue throughout the week and into next weekend. Join us tonight at 5:30pm and 10pm for updates.