Northwest Montana Regional Forecast
Includes Lincoln and Sanders Counties ( Libby, Troy, Eureka, Yaak, Bull Lake, Noxon, Heron, Trout Creek, Thompson Falls, and The Cabinet Mountains)
Issued Wednesday February 20, 2019 - 8:20 p.m.
Wednesday night…Mostly cloudy in the evening with isolated snow showers then becoming partly cloudy overnight. Cold with lows from 5 below zero to 10 above zero with mid single digits around 5000 feet. Light east wind except east wind 5 to 15 mph along the Kootenai River between Troy and Libby and along the Clark Fork River between Heron and Noxon. Ridge top winds northeast 10 to 20 mph.
Thursday...Variable clouds with isolated snow showers, mainly over the higher terrain. Highs in the mid 20s to lower 30s with mid teens around 5000 feet. Local east to northeast wind 5 to 15 mph in the morning decreasing by afternoon.
Thursday night…Partly cloudy in the evening then increasing clouds after midnight with a slight chance of light snow showers near the Canadian border. Lows from 5 below zero to 10 above zero with mid single digits around 5000 feet. Light wind.
Friday…Mostly cloudy with a chance of light snow except light snow becoming likely by afternoon along and west of the Cabinet Mountains. Local accumulations of up to 1 inch possible along and west of the Cabinet Mountains. Highs in the mid 20s to lower 30s with mid teens around 5000 feet. Light southwest wind.
Extended Outlook (Saturday through Wednesday)
Saturday…Cold with snow showers likely. Lows in the teens to near 20 with mid teens around 5000 feet. Highs in the upper 20s to mid 30s with upper teens around 5000 feet.
Sunday through Wednesday…Cold with a slight chance of snow showers. Lows from 15 below zero to 10 above zero with near zero around 5000 feet. Highs in the 20s to near 30 with lower teens around 5000 feet.
In-Depth Weather Discussion for Northwest Montana/Rockies
Issued 02/20/2019 8:30 p.m.
A bright but somewhat cloudy day on Wednesday with continued below average temperatures around 10 or so degrees below average will give way to another cold night tonight with some areas dropping down below zero once again. Any lingering instability snow showers will likely quickly die out before midnight as the dynamics and instability move further south. Still a fair amount of cloud around on Thursday with continued cool temperatures although the higher late February sun angle will help to take the nip out of the air and generally light winds will also help. Clouds look to increase after midnight on Thursday night in response to the next shortwave upper trough moving into the area but clouds will likely not move in quickly enough to prevent a rapid drop in temperatures and in fact more areas may dip down to near zero or below once again before cloud cover moves in and begins to moderate temperatures. Some weak lift brushes along the Canadian border Thursday night and with the cold airmass in place a few light snow showers should develop especially over the higher terrain. Westerly flow increases more on Friday with snow becoming likely by afternoon along and west of the Cabinet Mountains with lift increasing along with surface convergence and added jet support. Not much wind is expected at this time although if you are planning any backcountry hiking above 7000 feet winds may be a bit gusty at that level. Snow will likely peak in intensity overnight on Friday into early Saturday morning before becoming more showery. Amounts do not look terribly impressive from this system either with perhaps 3 to 6 inches in the valleys and 5 to 10 inches in the mountains which would qualify for a snow advisory. Cold temperatures are here to stay with continued below average temperatures that will likely only get colder still as we head into next week. A large and very cold upper level low pressure will sprawl across much of Canada with our region on the southwestern flank of this monster broad trough thus continued northwest flow along with low heights and thicknesses in the atmosphere will serve to keep both high and low temperatures well below average along with periodic chances for more snow. The snow will not have much water content with it so unfortunately the snowpack will likely remain below average, yes you did read that right, below average as the snowfall of the past several weeks has had very little water content and thus our snowpack is running around 80 to 85 % of normal for this time of year despite the larger amounts of snow on the ground. Will need to watch to see how the Pacific jet stream interacts with this cold upper low as we may see a heavy snow pattern develop across our region and some models are in fact showing that but I do not have enough confidence in this scenario yet. We will also need to watch to see what happens next week with now tropical storm Wutip in the West Pacific likely strengthening to typhoon status and affecting Guam. If and when Wutip recurves to the north and if it phases with the westerlies could have significant impacts on our weather towards the end of next week into the first week of March. Stay tuned and keep checking back often.