A Winter Storm Warning is in effect for much of greater Birmingham.  A storm was expected to hit starting early Tuesday, dropping snow, sleet, and freezing rain.  Fox 6 chief meteorologist JP Dice said the biggest threat is icy roads. "I expect icy roads, especially near the I-20 corridor ... through 10 AM." He says the area affected could stretch well north or south of the interstate.    Many school systems announced plans to close Tuesday, and Gov. Robert Bentley declared a state of emergency.