Marine Weather and Tide Forecast for Polson, MT

FXUS65 KMSO 132105 AFDMSO

Area Forecast Discussion National Weather Service Missoula MT 205 PM MST Mon Jan 13 2025

DISCUSSION

KEY MESSAGES:

- High confidence (70 to 90%) for the coldest air mass of the season to descend upon the Northern Rockies next weekend

Water vapor imagery indicates that moisture continues to circulate around the ridge and into the Northern Rockies. Stratus cloud cover remains in place, and the influx of additional moisture supports ongoing chances for flurries or light snow showers through this evening. However, cloud cover is expected to decrease overnight south of I-90 as drier air moves in, accompanied by strengthening surface high pressure. This clearing will allow for colder temperatures to develop in these areas overnight.

Westerly flow remains on track to bring mild and breezy conditions on Thursday as a trough approaches the region.

The primary focus continues to be the Arctic frontal passage expected on Friday, which could bring snow impacts initially and much colder temperatures over the weekend. Forecast uncertainty remains regarding the upper-level flow and the intensity of the Arctic intrusion, as model clusters suggest three potential scenarios:

1. A well-defined trough digging west of the region, pulling very cold air into the Northern Rockies.

2. A northerly flow pattern that brings cold conditions, but not overly extreme.

3. A northwesterly flow pattern, the mildest of the three, which would lead to cooler temperatures, only 5-10 F below normal.

Despite these differences, all scenarios support below-average temperatures, and confidence remains high for a significant cooldown. Models consistently agree that the coldest temperatures will occur before Tuesday, January 21, with a gradual warming trend and increased chances for snow thereafter.

Snowfall predictions vary widely from late Thursday through Friday, with general expectations ranging from a trace to 3 inches, while a few outlier models suggest locally higher amounts.

Preparedness Recommendations

1. Slick Roads: Light snow and freezing temperatures may create icy conditions. Drive cautiously, allow extra travel time, and maintain safe distances.

2. Cold Temperatures: Prepare for frigid conditions, with temperatures dropping below zero over the weekend. Protect pipes, ensure heating systems are functional, and dress warmly.

3. Livestock Protection: Provide shelter and windbreaks for newborn and vulnerable livestock. Ensure access to feed and water to minimize cold-related stress.
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