Possible versus expected
The essential difference is simple: a watch means conditions are possible; a warning means they are expected. The National Hurricane Center typically issues a watch about 48 hours before the anticipated arrival of tropical-storm-force winds and a warning about 36 hours beforehand. The clock is based on those earlier winds—not the arrival of the hurricane’s center—because outdoor preparation becomes dangerous before the eye approaches.
A hurricane watch concerns the possibility of sustained winds of at least 74 mph. A hurricane warning says those conditions are expected somewhere in the designated area. Tropical-storm alerts cover sustained winds of 39 to 73 mph. A storm-surge watch or warning concerns water moving onto normally dry land and is separate from the wind category.
What to do during a watch
Review the household plan, medicines, documents, fuel, batteries and pet needs. Know your evacuation zone and alternate routes. Charge phones and backup batteries. Secure loose items and finish window protection while doing so remains safe. Follow local government and your National Weather Service office because instructions are based on local risks, not only the forecast cone.
What to do during a warning
Finish preparations and stop outdoor work as conditions deteriorate. Leave immediately if officials order an evacuation. If you are outside an evacuation zone and instructed to stay, choose an interior room away from windows. Maintain several ways to receive alerts and do not depend on one phone or an internet connection.
The cone does not show every hazard
The forecast cone represents the probable area for the storm’s center, not the storm’s size. Wind, rain, tornadoes, surf and flooding can extend far outside it. A lower-category hurricane can still produce deadly flooding, and a centerline that shifts away can leave serious local effects. Local instructions take priority over personal interpretations of the map.