BOZEMAN – The next weather maker is another strong pacific storm system that will have a significant impact on travel across the Pacific NW, Idaho, and western Montana.
Areas of greatest concern will be those mountain passes on the Montana-Idaho state line tonight through Saturday night.
Lookout, Lolo, Lost Trail passes will see moderate to heavy snow tonight into Saturday and this includes 4th of July pass in Idaho along with much of eastern Washington State.
West Yellowstone into Island Park, Idaho will be another area of concern. Most of eastern Idaho (including Island Park) is under a Winter Storm Warning tonight through Tuesday evening. Impressive snow accumulations of one to four feet are possible along with wind gusts over 45 mph. West Yellowstone to Big Sky to Cooke City could pick up 4” – 6” of snow tonight through Sunday.
Lesser impacts are likely for Monida Pass, Big Hole Pass, Chief Joseph Pass, Wisdom to Wise River. This region is under a Winter Weather Advisory. Snow and wind will produce difficult to hazardous travel conditions.
Snow accumulations tonight through Sunday: Valleys 3” – 6”, mountains 6” – 12” along with gusty winds to 45 mph.
The rest of SW Montana will see scattered snow showers tonight through Sunday with minor accumulations for most valleys and a couple of inches for area mountain passes. But gusty winds along with periods of snow will pose a challenge to those traveling locally this weekend.
Strong westerly flow will also produce very strong surface wind gusts in wind prone areas of SW Montana with possible gusts over 65 mph in the Livingston area. There is a wind advisory up tonight into Saturday morning for the Livingston area so high profile vehicles use caution if traveling I-90.
ARCTIC BLAST UPDATE
An arctic blast is still on track to drop down into Montana beginning Sunday along the Hi-line and slowly digging southward Monday into Tuesday.
Extremely cold temperatures will develop for most of Northern and central Montana with daytime highs and morning lows well below zero. Forecast models have been very consistent with their forecast, model run to model run, which gives forecasters a higher degree of confidence.
Western and SW Montana models have been very inconsistent lately which gives us a lower degree of confidence. Some model runs show the arctic air arriving Tuesday morning and other runs show the arctic air remaining just outside of our region. This poses a very difficult challenge to our forecasts. The worst cases scenario will be lows -5 to -15 below or colder Tuesday morning especially east of the divide and best-case scenario is lows down around or slightly below zero Tuesday and Wednesday. We will continue to update the forecast highs and lows daily and will adjust based on latest model runs.
Western and SW Montana models have been very inconsistent lately which gives us a lower degree of confidence. Some model runs show the arctic air arriving Tuesday morning and other runs show the arctic air remaining just outside of our region. This poses a very difficult challenge to our forecasts. The worst cases scenario will be lows -5 to -15 below or colder Tuesday morning especially east of the divide and best-case scenario is lows down around or slightly below zero Tuesday and Wednesday. We will continue to update the forecast highs and lows daily and will adjust based on latest model runs.
