An upper level low (shaded area) is moving down from the the North and will bring cold Arctic air in behind it. A new cold front will move in from Canada and push the cold air down from the North. This front will be weak and produce very little precipitation which could fall in the form of snow flurries. A cold blast of Arctic air will follow Sunday, maybe snow flurries, but again no accumulation expected, so far anyway. The colder weather will last into the beginning of next week.

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For the Willamette Valley:  Mostly cloudy & cold tonight more fog & freezing fog low 22-25. A mix of clouds and sun Saturday after morning fog and freezing fog (watch out for slippery roads) and cooler high 36-39. Partly cloudy at night low 24-27. Partly cloudy Sunday with a slight (20%) chance of light snow showers high in the low to mid 30s. Slight (20%) chance of snow showers at night and colder low in the mid teens (yes I said teens). Monday will see a mix of clouds and sun high 34, then partly cloudy at night low in the upper teens to 20. A mix of clouds and sun again Tuesday high near 38. Partly cloudy with just a slight (20%) chance of rain at night low 24. Wednesday and Wednesday night will be mostly cloudy with a (50%) chance of rain (could see a snow flurry mixed in mainly late night and early morning) high 40 low 30. Mostly cloudy with a (50%) chance of rain  Thursday Through Friday highs near 40 low in the mid 30s Thursday night .

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For the Umpqua Basin the weather conditions will be just about the same as the Willamette Valley through Friday so bundle up.

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For the entire OregonCoast: A FROST ADVISORY IS IN EFFECT FROM MIDNIGHT TONIGHT THROUGH 9 AM SATURDAY. A FREEZE WATCH IS IN EFFECT FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING. A FREEZE WATCH IS IN EFFECT FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

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For the Cascades:  The snow level will stay below the passes tonight through next Friday with the exception of Monday night when the free air freezing level will be at 3,000′ because there should be no precipitation overnight.