401 FXUS65 KMSO 082121 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 221 PM MST Fri Feb 8 2019 ...SNOW...BLOWING SNOW...VERY COLD WIND CHILL ACROSS NORTHERN ROCKIES THROUGH SATURDAY... .DISCUSSION... A significant push of arctic air is still on track to impact the Northern Rockies tonight through Saturday. The initial push of cold air has began to cross over the Continental Divide and is currently moving into the Flathead Valley. Northeast to easterly winds will increase dramatically across northwest Montana tonight due to the presence of a strong pressure gradient as cold dense air banks along the Continental Divide. Winter Storm Warnings have been issued for areas in northwest Montana near the divide for a combination of snow, blowing and drifting snow, and dangerous wind chills creating hazardous conditions. The greatest impacts will be felt in Flathead and Mission Valley, and for areas along Highway 2 from Columbia Falls through Badrock Canyon up through Marias Pass; The I-90 corridor east of Missoula through Butte, MT-200 through Clearwater Junction and Helmville, and for areas along Highway 12 from Garrison Junction through McDonald Pass will also see severe impacts due the combination of blowing and drifting snow and dangerous wind chills. In addition, several inches of freshly fallen fluffy snow across northwest Montana will create ideal conditions for blowing snow and drifting, given the low liquid water content of the snow. The Missoula and Bitterroot valleys will see a period of blowing and drifting snow tonight through Saturday morning as the arctic boundary pushes through. While snowfall accumulations will be light, gusty winds will create areas of blowing snow and dangerous wind chills will approach 20 below by Saturday morning. Very cold air will settle into northwest and west central Montana tonight through Saturday. High temperatures will struggle to get above zero north of the I-90 corridor. Breezy easterly to northeasterly winds will continue and sub-zero wind chills can be expected! Exposed skin will experience frostbite in a matter of minutes! Also, livestock, particularly newborns, and domestic pets that live outdoors will be at high risk of exposure in these wind, cold conditions. Very cold wind chills of 20 to 40 degrees below zero will continue through Sunday morning. There are still indications that another snow producing weather system will move through the region Sunday into Monday. This weather pattern has potential to produce widespread snow accumulations of many inches and could result in bigger snow event for north-central Idaho. For those who enjoy snow, next week looks quite favorable. There will be a potential for several bouts of moderate to heavy snowfall Tuesday into next weekend. The overall pattern favors periodic “overrunning” as moisture rides over the top of cold air in place leading to widespread precipitation. Timing differences exist as to when the rounds of snow may occur but Tuesday/Wednesday and again Friday into Saturday appear most likely. Temperatures should remain 5 to 15 degrees below normal but have the potential to be even colder if arctic air sneaks back over the Divide as some forecast models suggest. Prepare for periods of hazardous travel next week due to the snowy and cold weather, stayed tuned as the details come more into focus. && .AVIATION...Arctic winds are moving over the Divide of Glacier National Park and into the Flathead Valley. Gusty winds, very low visibility and dangerous wind chills are the main threats for tonight across the region. East and northeast winds of 35 to 45 knots will be common with the passage of the arctic as is moves southwestward tonight. The lowest visibility is expected along and just west of the Divide. Obscured terrain will remain through tonight. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory until 2 PM MST Saturday Missoula/Bitterroot Valleys. Winter Weather Advisory until 2 PM MST Saturday Lower Clark Fork Region. Winter Storm Warning until 2 PM MST Saturday Flathead/Mission Valleys. Winter Storm Warning until 2 PM MST Saturday West Glacier Region. Winter Storm Warning until 2 PM MST Saturday Kootenai/Cabinet Region. Winter Weather Advisory until 2 PM MST Saturday Bitterroot/Sapphire Mountains. Winter Storm Warning until 2 PM MST Saturday Potomac/Seeley Lake Region. Winter Storm Warning until 2 PM MST Saturday Butte/Blackfoot Region. ID...Winter Weather Advisory until 1 PM PST Saturday Northern Clearwater Mountains. && $$