Weather Underground Forecast for Saturday, Dec. 17, 2011.
High pressure over most of the nation was expected to lead to dry and mild weather on Saturday. A ridge of high pressure built from the Rocky Mountains, over the Plains, and into the Eastern U.S. This system was expected to push moisture away, bringing sunny skies and dry conditions to most of the nation. Cool temperatures were expected to return to the East as the leading edge of this system pulled in cold air from Canada. Highs were expected to range in the 40s across the Mid-Atlantic states, while the Midwest was expected to see highs in the 30s. To the north, a trough of low pressure sweeping through central and eastern Canada was expected to push a trough of low pressure over the Great Lakes. This was expected to allow for light and scattered snow showers to develop across most of the Upper and Lower Great Lakes. Snowfall accumulation was expected to range around one to two inches. Significant snowfall was not expected.
Meanwhile in the West, a low pressure system spinning over southern California and Baja California was expected to continue strengthening on Saturday. The system was expected to slowly advance eastward and into the Southwestern U.S. At the same time, flow around this system was expected to pull moisture in from the Pacific and allow for showers to develop by evening. Light rain showers and high elevation snow showers were expected to spread into Arizona throughout the day. The rest of the western U.S will remain under high pressure with dry and mostly sunny conditions.
Temperatures in the Lower 48 states Friday ranged from a morning low of -6 degrees at Alamosa, Colo. to a high of 82 degrees at Crystal River, Fla.