Weather

Update: Major change in the weather late week

Posted: Nov 6, 2012 2:34 PM by Meteorologist Mike Heard
Updated: Nov 6, 2012 4:09 PM

Above normal temperatures continued today across Montana but in just a few days from now we will see well below normal temperatures and plenty of snow.

Forecast models continue to show a major change to the weather pattern beginning Thursday across Montana. The combination of Arctic air moving in from the north and a moist pacific storm to our south will collide and produce widespread snow late Thursday into Friday and possibly into Saturday morning.

Winter Storm Watches are up for 75% of the state Thursday into Saturday morning. Conditions look favorable for moderate to heavy snow to impact all mountain passes and valley floors as well. Winter Storm Watches are issued well ahead of an approaching storm system. As the event approaches NWS will upgrade the watch to a winter storm warning or advisory.

Early snow accumulation forecasts call for 5"-10" of valley snow here in southwest Montana with up to or over a foot in the mountains. Timing will be critical for this over-running event and it depends upon how fast or slow the Arctic air digs southward. If it is delayed we may not see as much snow as predicted, on the other hand, if the Arctic air rushes in earlier on Thursday we could see more snow than predicted.

Central Montana will see some of the heaviest snowfall accumulations with 6"-12" at lower elevations and several feet over the mountains.

A pressure gradient will also set across the state thus wind will be a major factor as well. North to East winds 15 to 25 gusting at times to 30 mph locally, stronger winds could be setting along the rocky mountain front. The combination of moderate to heavy snow bursts, Arctic air and gusty winds will produce hazardous travel conditions Thursday night into Friday. Wind chills could fall below zero and visibilities could be under a half mile at times.

The snow should taper off west to east across the state Saturday. As skies clear, fresh snow on the ground and lingering Arctic air at the surface Sunday morning lows will be very cold and most of could fall slightly below zero.

I'll have an updated forecast tonight at 5:30pm and at 10pm. Morning Meteorologist Matt Elwell will update the forecast Wednesday morning starting at 5:30am.