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Record-breaking October snow and cold in store for Western Montana

Snow, wind, and arctic air arrive Friday afternoon and evening
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Posted at 4:28 PM, Oct 22, 2020
and last updated 2020-10-22 19:19:44-04

MISSOULA — An unprecedented October storm is set to arrive in Western Montana Friday afternoon and last through Saturday afternoon.

With this storm we will discuss a few things: record-breaking snow amounts, record-breaking cold, and wind.

NORTHWEST

SNOW: Snow amounts will start to add up in the northwest corner first as this storm system arrives in the northwest around 8-10 AM Friday morning.

Snow will be light at first for all areas but will grow increasingly high in intensity as the afternoon and evening progress.

The heaviest amounts of snow will likely occur in the early evening hours even in valleys.

Kalispell is likely to get closer to 1-3” of snow during these evening hours with most accumulation occurring on unpaved surfaces. Places closer to the northwest corner, like Libby/Eureka, will likely see closer to 1”.

WIND/COLD AIR: The two go almost hand in hand. As cold air infiltrates the area, wind will pick up.

The northwest could see gusts up to 30-40 MPH. During this time snow will also be falling.

Wind around Flathead Lake will also be high.

***Roadways along the southwest side of the lake need to be careful from spray freezing on roadways.

Reduced visibility is possible as drifting and blowing snow are likely to occur Friday night into Saturday morning.

Frigid air moves in and weekend highs will be sub-freezing with lows in the single digits and negatives.

WEST-CENTRAL

Snow makes its way down to the I-90 corridor and west-central Montana around lunch time and mid-afternoon.

Again, slushy snow will fall in valleys as temperatures will be hovering slightly above freezing. Initial accumulation will be on unpaved surfaces.

By about 5-6 PM snow less water-rich as temperatures drop.

The largest amounts of snow are expected along the I-90 corridor from Lookout Pass to Lolo Pass, down into the northern Bitterroot Valley, up to Evaro Hill, and over as far is MacDonald Pass.

The timing of the heaviest amounts of snow will be around 8-10 PM Friday night.

During this time snow rates will increase significantly.

Totals in the Missoula Valley and surrounding areas will be closer to 4-6” while upper elevations will see totals over the half-foot mark.

WIND/COLD: The arctic air arrives in West-Central Montana a little later Friday evening. Around 7-8 PM wind will start picking up and gusts around 35-40 MPH. Gusts up to 50 MPH are possible in canyons such as Hellgate and the Rattlesnake.

**** BLIZZARD-LIKE CONDITIONS ARE POSSIBLE IN THESE AREAS FRIDAY NIGHT FROM BLOWING SNOW.

Visibility will be significantly reduced.

Cold air decreases highs to sub-freezing Saturday and Sunday, and lows Saturday night and Sunday night will drop to the single digits and negatives.

SOUTHWEST

The Bitterroot and southwest Montana get the incoming snow a little later in the early evening (4-6 PM).

This snow/moisture will be competing with warmer winds moving in from the southwest in the late afternoon, so the Bitterroot Valley will likely also see slush to begin the evening before converting to less water-rich snow later in the night.

The Bitterroot Valley will likely get closer to 3-5” of snow accumulation Friday-Saturday (especially in the northern Bitterroot Valley), and upper elevations will get closer to half a foot to a foot of snow.

Wind will reduce visibility starting Friday! Please drive carefully during this storm.

WARNINGS/ADVISORIES

Winter Storm Warnings are in effect Friday through Saturday for most of our area.

A Winter Weather Advisory was issued for the northwest part of the state.

Areas across the I-90/HWY-200 corridor and north go under a Winter Storm Warning starting at noon on Friday.

The Missoula and Bitterroot valleys start the Winter Storm Warning at 3 PM Friday, and does the rest of our area south of the I-90 corridor including the Bitterroot and Sapphire Mountains.

A Winter Weather Advisory is in effect starting at noon for areas along HWY 200 east of Happys Inn.

Please take the extra precautions you need if you have to travel this weekend.