The Nation's Weather 12.22.09

By WEATHER UNDERGROUND (AP)

Messy winter weather was forecast to continue Tuesday over the Northern U.S. as a low pressure system tracked over the Pacific Northwest and into the Northern Plains. This system was expected to obtain ample moisture from the Pacific Ocean and continue spreading scattered rain showers with periods of heavy snow at higher elevations.

Authorities issued a winter weather advisory over the region because up to 6 inches of snowfall was expected to fall over the Cascades and 1 to 3 inches on the Northern Rockies. Less than a half of an inch of rain was forecast at lower levels.

As this system strengthened in the West, the Northern and Central Plains was forecast to see increasingly cloudy skies. This system was expected to trigger a weak trough of low pressure, leading the system eastward across the Central U.S. While the trough was weak, it was forecast to possibly kick up scattered flurries over the Northern Plains and Upper Midwest.

A sloppy combination of snow and freezing rain was forecast for the Central Plains on Tuesday. The region was on the brink of a blizzard warning as strong winds were expected to move in from the West. Strong winds with gusts up to 29 mph were anticipated over much of the Plains, making travel and road conditions dangerous.

High pressure was expected to continue dominate the East Coast, bringing plenty of sunshine with highs in the South near 60, while the Northeast and New England were forecast in the 30s.

Temperatures in the Lower 48 states Monday ranged from a low of -9 degrees at Gunnison, Colo. to a high of 76 degrees at Harlingen, Texas.