Clear skies, calm winds and longer autumn nights combine to form dense fog and frost — know what to inspect on your car before that first chilly commute.

To understand how this monumental El Niño will shape our winter, NOAA has a network of instruments in the Pacific.

We have the maps you need to monitor the tropics, including tracks, current weather and other areas to watch.

A frontal boundary is stalled out across the Midwest and Central Plains, leading to a multi-day flood threat. Cities like Chicago need to be prepared.

A coastally trapped wave of warm water is creeping toward California, pushing sea levels higher. The real danger comes when winter storms arrive.