Despite atmospheric rivers to the west and Alberta clippers to the east, the Missoula area looks stuck in a funk of foggy drizzle for mid-January.
Likewise, the chance of a January thaw with grass reappearing and flowers threatening to bud in the Missoula Valley appears slim, according to current National Weather Service forecasts.
“There’s a huge range of possibilities,” Missoula NWS meteorologist Jeff Kitsmiller said on Thursday. “We could see a cold air mass bump up against us, but there’s not a lot of confidence in that. And the atmospheric river will go so far north, we may only get little pieces of it. It’s mostly going to hit the British Columbia coast and die off quickly.”
Meanwhile, the fast-moving, low-pressure Alberta Clipper moving southeast out of Canada into the U.S. Midwest has had limited impact along the Rocky Mountain Front this week, where temperatures have been in the low 40s. Alberta Clippers typically bring strong winds but little snow or other precipitation to the plains.
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Between those two, the Missoula and Bitterroot valleys must put up with periods of dense fog and stagnant air for the next few days.
Friday in Missoula could get a high temperature of 39, but drop to 17 in the evening to turn all the day's slush into ice. Highs on Saturday and Sunday should be around 32. Monday's Martin Luther King holiday might get a little snow, but also some rain as the temperature climbs to 42. Rain or snow should persist through the evening, turning to mostly snow before dawn Tuesday.
The Hamilton area will see a high of 41 with a 20% chance of snow Friday morning. Friday night should drop down to 24, followed by a partly sunny Saturday and a high of 43. By Monday, the high could reach 45, but expect rain or light snow in the evening.
The warm, wet weather has produced tricky conditions in the backcountry, according to the Thursday forecast of the West Central Montana Avalanche Center. That can produce considerable risk of wet-slab avalanches at lower elevations below 5,000 feet, although colder temperatures at higher elevations have stabilized the snowpack to moderate-risk status except for isolated wind slabs.
Missoula-area Januarys typically have high temperatures around 35 and lows of 20. But in 2020, the end of the month averaged 5.6 degrees above normal, with some days hitting 45 degrees. So did 2019, although that was followed by a teeth-rattling blizzard in mid-February.