A great place to look for current predictions of hazardous weather in the United States is this page from the Storm Prediction Center in Norman, Oklahoma.
A great way to stay informed of weather and emergency information is to tune into the NOAA Weather Radio All Hazards broadcast. To hear the broadcast, you will need a transmitter, which can be obtained at many retail stores. This service is also available through live streaming over the internet.
The United States Geological Society has a section of its home page devoted to natural hazards. Click on the Natural Hazards Gateway.