US

Weather Underground Forecast for Monday, March 22, 2010.

Monday's main weather event will take place in the eastern third of the nation as a strong storm system in the Southeast advances northeastward. This moisture rich system will continue to produce numerous swaths of light to moderate showers, periods of heavy rainfall, high elevation snowfall, and possible thunderstorms across the Eastern Valleys, the Mid-Atlantic, and southern New England. The strongest amounts of precipitation are expected to fall from the Ohio Valley through the Mid-Atlantic coast. While gloomy weather conditions are expected to last across these regions throughout the day, temperatures will remain on the mild side during the afternoon.

Behind this system, high pressure will bring drier and warmer weather to the Central and Southern Plains.

To the north, a Pacific frontal system will trek across the Intermountain West and into the Northern Plains on Monday. Energy associated with this system will trigger areas of mountain snow and rainfall across the valleys and plains. As this system treks eastward, onshore flow will keep the Pacific Northwest under variable cloud coverage and a chance of showers.

Meanwhile, after low clouds and areas of fog in the morning, fairer weather will return to California as high pressure begins to build over the state. Pleasant weather activity is also expected across the Four Corners.

Temperatures in the Lower 48 states Sunday ranged from a low of -10 degrees at Shirley Basin, Wyo. to a high of 85 degrees at Miami, Fla.