The Nation's Weather 12.05.09

By WEATHER UNDERGROUND (AP)

Early season snow was expected across the Appalachians on Saturday as an intense, low-pressure system developed off the Eastern Seaboard.

Fueled by warm Gulf Stream waters, the storm was forecast to rapidly intensify throughout the day helping to enhance snow amounts in the region. In addition to snow in the higher elevations, heavy rain and strong winds were anticipated at the coast. Exceptionally cold air was expected to fill in behind the storm as it moved toward the northeast throughout the day, and some of the rain in the coastal plain was to switch over to snow as it tapered off.

Overnight the cold air was forecast to deepen and low temperatures to drop to their lowest readings of the winter so far.

Temperatures in the Plains were to also be on the cool side Saturday, but clear skies were expected to bring a sunny and crisp day to the region with no precipitation anticipated until the late evening when some snow showers were to slide out of the Northern Rockies.

The snow showers in the Rockies were forecast to be triggered by a weak, low-pressure system sliding through southern Canada. Precipitation was to be most intense in the morning hours, tapering off as the system slid eastward.

The West Coast was expected to see another clear cool day Saturday, a high pressure remains in control of the weather pattern. In the northwest, temperatures were to be cold while the rest of the region was to see chilly temperatures. Highs along the California coast were forecast to be in the 60s south of Point Conception, and in the 50s farther north. In Washington and Oregon, many locations were to see temperatures flirting with the freezing mark for much of the day.

Temperatures in the Lower 48 states Friday ranged from a low of -21 degrees at Island Park, Idaho to a high of 84 degrees at Kendall, Fla.