853 FXUS65 KMSO 141721 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1021 AM MST Mon Jan 14 2013 .UPDATE...Snow was increasing across northern Idaho and into western Montana this morning. Added White Bird Grade in north- central Idaho to the Winter Weather Advisory mix. Also, a Flood Watch was issued for the Salmon River near Salmon, Idaho for ice jam flooding potential. && .AVIATION...A wide area of stratus is lowering this morning in Idaho and western Montana and will continue to do so through today. An area of snow to the north and west of the region will spread through Idaho and western Montana through this morning with widespread lowered visibilities likely by this morning due to light snow. Majority of the region will have obscured terrain and snow accumulations into tonight. Some drier air will arrive on Tuesday and should help to decrease snow coverage and promote less cloud cover. && .PREV DISCUSSION... /ISSUED 818 AM MST Mon Jan 14 2013/ UPDATE...Snow was advancing across northern Idaho and into western Montana this morning. The temperature/moisture profile at the lower levels favorable for snow growth and Winter Weather Advisories remain in the weather picture for today. Snow falling on top of already icy/hard-packed snow covered road will make driving condition very slick. AVIATION...A wide area of stratus is lowering this morning in Idaho and western Montana and will continue to do so through today. An area of snow to the north and west of the region will spread through Idaho and western Montana through this morning with widespread lowered visibilities likely by this morning due to light snow. Majority of the region will have obscured terrain and snow accumulations into tonight. Some drier air will arrive on Tuesday and should help to decrease snow coverage and promote less cloud cover. PREV DISCUSSION... /ISSUED 324 AM MST Mon Jan 14 2013/ .Snow accumulations are expected through today and into tonight... .Cold temperatures will continue to lead to ice jam concerns... DISCUSSION...Radar returns are starting to enhance around Spokane early this morning in association with the next weather system moving into the region. Model guidance seem to be doing an okay job with the moisture placement but there does seem to be some struggle with the amount of precipitation, which is not uncommon in a weakly forced/cold environment like the one we have. The profile continuous to favor snow that is expected to gradually increase through the morning throughout the region. Current conditions and model trends maintain that the winter weather advisories for today and tonight are still relevant with a couple of inches of low density snow by this evening in most places. Snow will gradually taper off tonight but there are some indications that light snow could linger into Tuesday. Temperatures will remain very cold with valley cold pools beginning to become more pronounced Tuesday afternoon and Wednesday morning. Wednesday through Sunday will see a ridge of high pressure become the dominant weather feature. Stable, dry conditions are expected with patches of valley fog developing. Surface based inversions will strengthen during the overnight periods with little if any mixing. In addition, valleys will remain colder than normal with a continuation of ice forming on areas rivers. AVIATION...A wide area of stratus is lowering this morning in Idaho and western Montana and will continue to do so through today. An area of snow to the north and west of the region will spread through Idaho and western Montana through this morning with widespread lowered visibilities likely by this morning due to light snow. Majority of the region will have obscured terrain and snow accumulations into tonight. Some drier air will arrive on Tuesday and should help to decrease snow coverage and promote less cloud cover. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY until 11 PM MST this evening Missoula/Bitterroot Valleys. WINTER WEATHER ADVISORY until 11 PM MST this evening Flathead/Mission Valleys. WINTER WEATHER ADVISORY until 11 PM MST this evening Potomac/Seeley Lake Region...West Glacier Region. WINTER WEATHER ADVISORY until 5 PM MST this afternoon Kootenai/Cabinet Region...Lower Clark Fork Region. WINTER WEATHER ADVISORY until 11 PM MST this evening Bitterroot/Sapphire Mountains. ID...WINTER WEATHER ADVISORY until 10 PM PST this evening ABOVE 2500 FEET FOR THE Lower Hells Canyon/Salmon River Region. WINTER WEATHER ADVISORY until 4 PM PST this afternoon Northern Clearwater Mountains...Orofino/Grangeville Region. WINTER WEATHER ADVISORY until 10 PM PST this evening Southern Clearwater Mountains. && $$ Follow us on Facebook and Twitter! https://www.facebook.com/US.NationalWeatherService.Missoula.gov https://www.twitter.com/NWSMissoula