The Nation's Weather 12.21.09

By WEATHER UNDERGROUND (AP)

The Pacific Northwest was forecast to experience another messy day on Monday as a strong low pressure system moved through the region. The system was expected to obtain ample moisture from the Pacific Ocean and pull cold air in from British Colombia, ensuring persistent cool weather with highs in the 20s and 30s and light rain over the region.

From 2 to 4 inches of new snow was anticipated over the Cascades and Northern Rockies, with less than a half of an inch of rain at lower elevations. Cool conditions with light and scattered showers were also forecast to extend into northern California.

Moving east, a low pressure system that dipped into the Upper Midwest from central Canada was forecast to bring another wintry day to the Great Lakes. This system was expected to slowly track eastward over the Great Lakes and kick up 1 to 2 inches of snowfall on Monday.

Elsewhere in the Central and Eastern U.S., high pressure was expected to continue building over the Mississippi and Ohio River Valleys, bringing a few patchy clouds with cool conditions. The North was forecast to remain in the 20s, while the Southeast was to see another sunny day with highs in the 50s. Relatively inactive weather was expected in the Plains on Monday.

Temperatures in the Lower 48 states Sunday ranged from a low of -13 degrees at Gunnison, Colo. to a high of 73 degrees at San Fernando, Calif.