Weather Underground Forecast for Wednesday, April 11, 2012. Unsettled weather will persist across the West Coast Wednesday and Thursday as a sereis of systems move through. The cold front that moved ashore Tuesday will continue to advance eastward. As a result, widespread rain with high elevation snow is expected across the Western U.S. Moderate to locally heavy snow showers will be possible over the Cascades and Sierras Wednesday. By Thursday, another Pacific system will move ashore, bringing another round of rain and mountain snow across California. In the middle section of the nation, a stationary front will continue to support scattered showers and thunderstorms over the Southern Plains and portions of lower Mississippi Valley. Severe thunderstorms will be possible over portions of Central and Southern High Plains. Large hail and damaging wind gusts will be the main threat. Isolated tornadoes cannot be ruled out as well. Apart from the precipitation, freeze watches and warnings have been issued for much of the Midwest Wednesday morning. Temperatures will fall below freezing. In the East, lingering scattered snow showers will persist over New England, eastern Great Lakes and portions of the Appalachians in the morning, changing to rain showers by noon. Temperatures in the Lower 48 states Tuesday have ranged from a morning low of 10 degrees at Watford City, N.D. to a high of 90 degrees at Needles, Calif.