PENDLETON, Ore. -- The National Weather Service warns that a deep low pressure system will move into the Northwest starting Thursday, bringing much cooler temperatures.

Snow levels will fall from 9,000 feet today to below 2,000 feet by Friday night.

Most of the precipitation will be rain showers, but several inches of snow can be expected in the mountains.

However, light snow showers also will be possible Friday night.

Showers will taper off Saturday, but daytime highs will reach into the 40s, with 30s in the mountains.

Cooler temperatures are expected to last through the beginning of next week, with another storm system arriving Sunday night.