Tornado Threat for Parts of Midwest, South

(CNN) -- Much-needed rain fell in bone-dry western Oklahoma on Tuesday, part of an unusually spring-like storm bringing high temperatures and the threat of hail, high winds and tornadoes to parts of the Midwest and South.

While a tornado watch is up for parts of western Oklahoma and North Texas until midday, the greatest threat of tornadoes is in parts of Arkansas, northern Louisiana and western Mississippi, CNN meteorologist Sarah Dillingham said.

Those storms could be at their most dangerous late Tuesday night into Wednesday morning, she said.

The National Weather Service's Storm Prediction Center categorized the risk for severe storms Wednesday as moderate.

In addition to the tornado threat, a long line of thunderstorms that will stretch from northern Louisiana as far north as Chicago and Grand Rapids, Michigan, will carry the threat of damaging winds into early Wednesday, Dillingham said.

Wind gusts could reach 80 mph in some areas -- enough to bring down trees and power lines, she said.

On Wednesday, the threat shifts farther east, with parts of Alabama, Georgia, Tennessee, Kentucky, South Carolina, North Carolina, Virginia and West Virginia at moderate risk of severe weather, including damaging winds and isolated tornadoes, the Storm Prediction Center said.

After the severe weather, a cold-weather system could bring snow and freezing rain to the Midwest, beginning Wednesday, and the threat of extremely cold weather in the northern Plains states and Upper Midwest, particularly on Thursday.