112 FXUS65 KMSO 071102 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 402 AM MST Sun Nov 7 2021 .DISCUSSION...The cold front that brought snow to the mountains last night has moved off to the east and south this morning. According to webcam imagery, the front brought a quick burst of 1 to 2 inches with gusty winds ranging between 30 and 40 mph in higher elevations above 4,000 feet. The temperature on top of Point 6 Mountain, north of Missoula is sitting at 18 degrees as of 2 am, 10 degrees colder than this time yesterday. This morning's radar is showing isolated showers across the region. Showers will persist today, mainly over the mountains over northwest Montana. Breezy south to west winds between 10 and 20 mph are expected through this afternoon. An upper level shortwave will move over northwest Montana tonight into Monday morning. With such a cold airmass in place, snow showers are possible at most elevations. Places like Thompson Pass, Lookout Pass, Yaak, US-2 between Libby and Marion, Olney and the Glacier Park region could pick up a dusting up to a inch and a half of snow. Upper level ridging will help put a stop to the shower activity later Monday, but the wind gradient begins to tighten especially over Idaho in response to a strong low pressure system offshore of the Pacific coast. Easterly winds will mainly be felt in the higher elevations Monday night, but places like the Camas Prairie in Idaho will see stiff southerly winds by Tuesday morning. We have raised the forecast winds there to reflect possible winds near 40 mph between Grangeville and Whitebird. There is a chance that the winds could be a little stronger than that. This could impact high profile vehicles traveling US-95. Besides the increased winds, a warm front will bring precipitation to north-central Idaho and along the Idaho and Montana border by daybreak Tuesday. Snow levels will be around 3,000 feet but will rise with time. Several inches of snow is possible for mountain passes along the border. A few valley locations could pick up some snow, but with warm ground temperatures, it may just accumulate on grassy surfaces. A strong cold front is expected to traverse the region by Tuesday evening and will drop snow levels and bring widespread showers and gusty winds. More accumulating snowfall is possible, especially across north- central Idaho mountains, but also across western Montana including valley locations down to 3000 feet. The region remains under unstable, cold and northwest flow into Wednesday which would keep the chance for rain and snow showers going. Clearing is possible by Thursday which would provide cold morning temperatures with patchy fog. What we call a "dirty ridge" is expected by next Friday and Saturday as subtropical moisture will move around and through the ridge into the region. As mentioned before, this would bring higher snow levels, milder temperatures and breezy conditions to the region. There are a few signs that point to unsettled weather with the potential for lower snow levels the following week (3rd week of November). An arctic airmass will build over interior Alaska into the Yukon territory this upcoming week. This cold and dense air will eventually want to travel southward. Ensemble models have been trending to have more ridging over Alaska which would enhance this potential. This pattern looks very La Nina-ish. The Polar jet across the Pacific continues to be very active and if we can get the right combination of Pacific moisture, good dynamics with cold, it could get quite interesting around here. Stayed tuned. && .AVIATION...Isolated rain and snow showers are expected across the Northern Rockies today. Shower activity could be more scattered across northwest Montana and confined mainly to the terrain. Expect periodic visibility and ceiling reduction. Gusty winds will be felt at all the terminals, generally under 25 knots. An upper level wave will bring more widespread snow showers across northwest Montana between 08/0300Z and 08/1700Z. GPI may experience a passing shower during this timeframe, but confidence is higher that the mountains will experience a majority of the activity. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory until 8 AM MST this morning ABOVE 4000 FEET for the Bitterroot/Sapphire Mountains. Winter Weather Advisory until 8 AM MST this morning ABOVE 4000 FEET for the West Glacier Region. ID...Winter Weather Advisory until 7 AM PST this morning ABOVE 4000 FEET for the Southern Clearwater Mountains. && $$