The lower Mississippi Valley will see widespread thunderstorms Wednesday as a piece of energy in the jet stream moves through the region.These storms will move eastward throughout the day, pushing into the Southeast by early afternoon. These storms are not expected to cause much trouble other than heavy rains and frequent lightning, but a few individual storms could become severe and cause wind damage.The Northwest will also see active weather Wednesday as a Pacific storm slams into the region. Heavy rain and high elevation snow will push into Oregon early in the day, then the bulk of precipitation will shift farther to the north, mainly focusing on Washington. The Olympic Peninsula will see some heavy snow accumulation in the high elevations, mostly above 5,500 feet. Snow levels in the Cascades will be lower, around 3,000 feet at the lowest.California will continue to see a warming trend Wednesday as high pressure builds strongly into the eastern Pacific. Temperatures throughout the state will rise well above normal for many locations, and could reach to near record levels. Warming is expected to continue through the end of the week.Temperatures in the Lower 48 states Tuesday ranged from a morning low of -6 degrees at Tomahawk, Wis., to a high of 84 degrees at Kendall, Fla.